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Baltazar Becerril
Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, UNAM, Apartado Postal 510-3, Cuernavaca, Morelos, 62250, Mexico

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Journal article
Published: 30 May 2020 in Toxicon
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In this communication the isolation, chemical and physiological characterization of three new toxins from the scorpion Centruroides baergi are reported. Their immunoreactive properties with scFvs generated in our group are described. The three new peptides, named Cb1, Cb2 and Cb3 affect voltage-dependent Na+ channels in a differential manner. These characteristics, explain the toxicity of this venom. Molecular interactions in real-time among these toxins and the best recombinant antibodies generated in our group, revealed that one of them was able to neutralize the main toxin of this venom (Cb1). These results represent an important advance for the neutralization of this venom and serve as the basis for generating new scFvs that will allow the neutralization of similar toxins from other venoms that have no yet been neutralized.

ACS Style

Ilse V. Gómez-Ramírez; Lidia Riaño-Umbarila; Timoteo Olamendi-Portugal; Rita Restano-Cassulini; Lourival D. Possani; Baltazar Becerril. Biochemical, electrophysiological and immunological characterization of the venom from Centruroides baergi, a new scorpion species of medical importance in Mexico. Toxicon 2020, 184, 10 -18.

AMA Style

Ilse V. Gómez-Ramírez, Lidia Riaño-Umbarila, Timoteo Olamendi-Portugal, Rita Restano-Cassulini, Lourival D. Possani, Baltazar Becerril. Biochemical, electrophysiological and immunological characterization of the venom from Centruroides baergi, a new scorpion species of medical importance in Mexico. Toxicon. 2020; 184 ():10-18.

Chicago/Turabian Style

Ilse V. Gómez-Ramírez; Lidia Riaño-Umbarila; Timoteo Olamendi-Portugal; Rita Restano-Cassulini; Lourival D. Possani; Baltazar Becerril. 2020. "Biochemical, electrophysiological and immunological characterization of the venom from Centruroides baergi, a new scorpion species of medical importance in Mexico." Toxicon 184, no. : 10-18.

Journal article
Published: 30 April 2020 in Molecular Immunology
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The present study evaluated the effect of the change in the orientation of the VH-VL variable domains to VL-VH on the physicochemical and functional properties of two scorpion toxin-neutralizing scFvs. The results showed that the level of expression of proteins obtained from the periplasm of E. coli is the factor mainly affected, either with an increase or decrease in the amount of protein recovered. Likewise, the functional recognition activity in the presence of a denaturing agent showed slight variations in the two orientations. In contrast, recognition and biological activity (neutralizing capacity) are maintained. At the interaction level, the change marginally modified the kinetic association and dissociation constants without significantly modifying the value of the affinity constants. Similarly, it was observed that the thermodynamic stability of the proteins did not show significant variations either. These results contrast with some reports of the effect of changing the orientation of domains, suggesting that it is not possible to predict which orientation of the variable domains of an scFv is more favorable or if they are equivalent, as in the case of scFvs previously matured by directed evolution techniques.

ACS Style

Lidia Riaño-Umbarila; Vianey Margarita Rojas-Trejo; José Alberto Romero-Moreno; Miguel Costas; Irving Utrera-Espíndola; Timoteo Olamendi-Portugal; Lourival D. Possani; Baltazar Becerril. Comparative assessment of the VH-VL and VL-VH orientations of single-chain variable fragments of scorpion toxin-neutralizing antibodies. Molecular Immunology 2020, 122, 141 -147.

AMA Style

Lidia Riaño-Umbarila, Vianey Margarita Rojas-Trejo, José Alberto Romero-Moreno, Miguel Costas, Irving Utrera-Espíndola, Timoteo Olamendi-Portugal, Lourival D. Possani, Baltazar Becerril. Comparative assessment of the VH-VL and VL-VH orientations of single-chain variable fragments of scorpion toxin-neutralizing antibodies. Molecular Immunology. 2020; 122 ():141-147.

Chicago/Turabian Style

Lidia Riaño-Umbarila; Vianey Margarita Rojas-Trejo; José Alberto Romero-Moreno; Miguel Costas; Irving Utrera-Espíndola; Timoteo Olamendi-Portugal; Lourival D. Possani; Baltazar Becerril. 2020. "Comparative assessment of the VH-VL and VL-VH orientations of single-chain variable fragments of scorpion toxin-neutralizing antibodies." Molecular Immunology 122, no. : 141-147.

Journal article
Published: 20 July 2019 in Toxins
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Many peptides in scorpion venoms are amidated at their C-termini. This post-translational modification is paramount for the correct biological function of ion channel toxins and antimicrobial peptides, among others. The discovery of canonical amidation sequences in transcriptome-derived scorpion proproteins suggests that a conserved enzymatic α-amidation system must be responsible for this modification of scorpion peptides. A transcriptomic approach was employed to identify sequences putatively encoding enzymes of the α-amidation pathway. A dual enzymatic α-amidation system was found, consisting of the membrane-anchored, bifunctional, peptidylglycine α-amidating monooxygenase (PAM) and its paralogs, soluble monofunctional peptidylglycine α-hydroxylating monooxygenase (PHMm) and peptidyl-α-hydroxyglycine α-amidating lyase (PALm). Independent genes encode these three enzymes. Amino acid residues responsible for ion coordination and enzymatic activity are conserved in these sequences, suggesting that the enzymes are functional. Potential endoproteolytic recognition sites for proprotein convertases in the PAM sequence indicate that PAM-derived soluble isoforms may also be expressed. Sequences potentially encoding proprotein convertases (PC1 and PC2), carboxypeptidase E (CPE), and other enzymes of the α-amidation pathway, were also found, confirming the presence of this pathway in scorpions.

ACS Style

Gustavo Delgado-Prudencio; Lourival D. Possani; Baltazar Becerril; Ernesto Ortiz. The Dual α-Amidation System in Scorpion Venom Glands. Toxins 2019, 11, 425 .

AMA Style

Gustavo Delgado-Prudencio, Lourival D. Possani, Baltazar Becerril, Ernesto Ortiz. The Dual α-Amidation System in Scorpion Venom Glands. Toxins. 2019; 11 (7):425.

Chicago/Turabian Style

Gustavo Delgado-Prudencio; Lourival D. Possani; Baltazar Becerril; Ernesto Ortiz. 2019. "The Dual α-Amidation System in Scorpion Venom Glands." Toxins 11, no. 7: 425.

Journal article
Published: 10 January 2019 in Toxins
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The recombinant antibody fragments generated against the toxic components of scorpion venoms are considered a promising alternative for obtaining new antivenoms for therapy. Using directed evolution and site-directed mutagenesis, it was possible to generate a human single-chain antibody fragment with a broad cross-reactivity that retained recognition for its original antigen. This variant is the first antibody fragment that neutralizes the effect of an estimated 13 neurotoxins present in the venom of nine species of Mexican scorpions. This single antibody fragment showed the properties of a polyvalent antivenom. These results represent a significant advance in the development of new antivenoms against scorpion stings, since the number of components would be minimized due to their broad cross-neutralization capacity, while at the same time bypassing animal immunization.

ACS Style

Lidia Riaño-Umbarila; Ilse V. Gómez-Ramírez; Luis M. Ledezma-Candanoza; Timoteo Olamendi-Portugal; Everardo Remi Rodríguez-Rodríguez; Guillermo Fernández-Taboada; Lourival D. Possani; Baltazar Becerril. Generation of a Broadly Cross-Neutralizing Antibody Fragment against Several Mexican Scorpion Venoms. Toxins 2019, 11, 32 .

AMA Style

Lidia Riaño-Umbarila, Ilse V. Gómez-Ramírez, Luis M. Ledezma-Candanoza, Timoteo Olamendi-Portugal, Everardo Remi Rodríguez-Rodríguez, Guillermo Fernández-Taboada, Lourival D. Possani, Baltazar Becerril. Generation of a Broadly Cross-Neutralizing Antibody Fragment against Several Mexican Scorpion Venoms. Toxins. 2019; 11 (1):32.

Chicago/Turabian Style

Lidia Riaño-Umbarila; Ilse V. Gómez-Ramírez; Luis M. Ledezma-Candanoza; Timoteo Olamendi-Portugal; Everardo Remi Rodríguez-Rodríguez; Guillermo Fernández-Taboada; Lourival D. Possani; Baltazar Becerril. 2019. "Generation of a Broadly Cross-Neutralizing Antibody Fragment against Several Mexican Scorpion Venoms." Toxins 11, no. 1: 32.

Journal article
Published: 01 January 2018 in Archives of Biochemistry and Biophysics
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This study investigated geographic variability in the venom of Centruroides sculpturatus scorpions from different biotopes. Venom from scorpions collected from two different regions in Arizona; Santa Rita Foothills (SR) and Yarnell (Yar) were analyzed. We found differences between venoms, mainly in the two most abundant peptides; SR (CsEv2e and CsEv1f) and Yar (CsEv2 and CsEv1c) identified as natural variants of CsEv1 and CsEv2. Sequence analyses of these peptides revealed conservative amino acid changes between variants, which may underlie biological activity against arthropods. A third peptide (CsEv6) was highly abundant in the Yar venom compared to the SR venom. CsEv6 is a 67 amino acid peptide with 8 cysteines. CsEv6 did not exhibit toxicity to the three animal models tested. However, both venoms shared similarities in peptides that are predicted to deter predators. For example, both venoms expressed CsEI (lethal to chick) in similar abundance, while CsEd and CsEM1a (toxic to mammals) displayed only moderate variation in their abundance. Electrophysiological evaluation of CsEd and CsEM1a showed that both toxins act on the human sodium-channel subtype 1.6 (hNav 1.6). Complete sequencing revealed that both toxins are structurally similar to beta-toxins isolated from different Centruroides species that also target hNav 1.6.

ACS Style

Edson Norberto Carcamo-Noriega; Timoteo Olamendi-Portugal; Rita Restano-Cassulini; Ashlee Rowe; Selene Jocelyn Uribe-Romero; Baltazar Becerril; Lourival Domingos Possani. Intraspecific variation of Centruroides sculpturatus scorpion venom from two regions of Arizona. Archives of Biochemistry and Biophysics 2018, 638, 52 -57.

AMA Style

Edson Norberto Carcamo-Noriega, Timoteo Olamendi-Portugal, Rita Restano-Cassulini, Ashlee Rowe, Selene Jocelyn Uribe-Romero, Baltazar Becerril, Lourival Domingos Possani. Intraspecific variation of Centruroides sculpturatus scorpion venom from two regions of Arizona. Archives of Biochemistry and Biophysics. 2018; 638 ():52-57.

Chicago/Turabian Style

Edson Norberto Carcamo-Noriega; Timoteo Olamendi-Portugal; Rita Restano-Cassulini; Ashlee Rowe; Selene Jocelyn Uribe-Romero; Baltazar Becerril; Lourival Domingos Possani. 2018. "Intraspecific variation of Centruroides sculpturatus scorpion venom from two regions of Arizona." Archives of Biochemistry and Biophysics 638, no. : 52-57.

Journal article
Published: 01 November 2017 in Toxicon
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The increment in the number of scorpion envenoming cases in Mexico is mainly associated to the rapid growth of the urban areas, and consequently, to the invasion of natural habitats of these arachnids. On the other hand, there is a great diversity of scorpion species, so it is indispensable to identify those of medical importance, which we now know are many more than the 7-8 previously reported as dangerous to humans. Because different LD50 values have been reported for the venom of the same species, probably due to variations in the experimental conditions used, in this work we determined the LD50 values for the venoms of 13 different species of scorpions using simple but systematic procedures. This information constitutes a referent on the level of toxicity of medically important scorpion species from Mexico and establishes the bases for a more comprehensive assessment of the neutralizing capacity of current and developing antivenoms.

ACS Style

Lidia Riaño-Umbarila; Everardo R. Rodríguez-Rodríguez; Carlos E. Santibañez-López; Leopoldo Güereca; Selene J. Uribe-Romero; Ilse V. Gómez-Ramírez; Edson N. Cárcamo-Noriega; Lourival D. Possani; Baltazar Becerril. Updating knowledge on new medically important scorpion species in Mexico. Toxicon 2017, 138, 130 -137.

AMA Style

Lidia Riaño-Umbarila, Everardo R. Rodríguez-Rodríguez, Carlos E. Santibañez-López, Leopoldo Güereca, Selene J. Uribe-Romero, Ilse V. Gómez-Ramírez, Edson N. Cárcamo-Noriega, Lourival D. Possani, Baltazar Becerril. Updating knowledge on new medically important scorpion species in Mexico. Toxicon. 2017; 138 ():130-137.

Chicago/Turabian Style

Lidia Riaño-Umbarila; Everardo R. Rodríguez-Rodríguez; Carlos E. Santibañez-López; Leopoldo Güereca; Selene J. Uribe-Romero; Ilse V. Gómez-Ramírez; Edson N. Cárcamo-Noriega; Lourival D. Possani; Baltazar Becerril. 2017. "Updating knowledge on new medically important scorpion species in Mexico." Toxicon 138, no. : 130-137.

Journal article
Published: 12 October 2017 in The FEBS Journal
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Light chain amyloidosis is a lethal disease where vital organs are damaged by the fibrillar aggregation of monoclonal light chains. λ6a is an immunoglobulin light chain encoded by the germ-line gene segment implicated in this disease. AR is a patient-derived germ-line variant with a markedly low thermodynamic stability and prone to form fibrils in vitro in less than an hour. Here, we sought to stabilize this domain by mutating some residues back to the germ-line sequence, and the most stabilizing mutations were the single-mutant AR-F21I and the double-mutant AR-F21/IV104L, both located in the hydrophobic core. While mutation Arg25Gly in 6aJL2 destabilized the domain, mutating Gly25 back to arginine in AR did not contribute to stabilization as expected. Crystallographic structures of AR and 6a-R25G were generated to explain this discrepancy. Finally, 6a-R25G crystals revealed an octameric assembly which was emulated into 6aJL2 and AR crystals by replicating their structural parameters and suggesting a common assembly pattern.DatabaseThe atomic coordinates and structure factors have been deposited in the Protein Data Bank under the accession numbers 5IR3 and 5C9K.

ACS Style

Oscar D. Luna‐Martínez; Alejandra Hernández‐Santoyo; Myriam I. Villalba‐Velázquez; Rosalba Sánchez‐Alcalá; Daniel A. Fernández‐Velasco; Baltazar Becerril. Stabilizing an amyloidogenic λ6 light chain variable domain. The FEBS Journal 2017, 1 .

AMA Style

Oscar D. Luna‐Martínez, Alejandra Hernández‐Santoyo, Myriam I. Villalba‐Velázquez, Rosalba Sánchez‐Alcalá, Daniel A. Fernández‐Velasco, Baltazar Becerril. Stabilizing an amyloidogenic λ6 light chain variable domain. The FEBS Journal. 2017; ():1.

Chicago/Turabian Style

Oscar D. Luna‐Martínez; Alejandra Hernández‐Santoyo; Myriam I. Villalba‐Velázquez; Rosalba Sánchez‐Alcalá; Daniel A. Fernández‐Velasco; Baltazar Becerril. 2017. "Stabilizing an amyloidogenic λ6 light chain variable domain." The FEBS Journal , no. : 1.

Journal article
Published: 01 September 2016 in Toxicon
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New approaches aimed at neutralizing the primary toxic components present in scorpion venoms, represent a promising alternative to the use of antivenoms of equine origin in humans. New potential therapeutics developed by these approaches correspond to neutralizing antibody fragments obtained by selection and maturation processes from libraries of human origin. The high sequence identity shared among scorpion toxins is associated with an important level of cross reactivity exhibited by these antibody fragments. We have exploited the cross reactivity showed by single chain variable antibody fragments (scFvs) of human origin to re-direct the neutralizing capacity toward various other scorpion toxins. As expected, during these evolving processes several variants derived from a parental scFv exhibited the capacity to simultaneously recognize and neutralize different toxins from Centruroides scorpion venoms. A sequence analyses of the cross reacting scFvs revealed that specific mutations are responsible for broadening their neutralizing capacity. In this work, we generated a set of new scFvs that resulted from the combinatorial insertion of these point mutations. These scFvs are potential candidates to be part of a novel recombinant antivenom of human origin that could confer protection against scorpion stings. A remarkable property of one of these new scFvs (ER-5) is its capacity to neutralize at least three different toxins and its complementary capacity to neutralize the whole venom from Centruroides suffusus in combination with a second scFv (LR), which binds to a different epitope shared by Centruroides scorpion toxins.

ACS Style

Everardo Rodríguez; Timoteo Olamendi-Portugal; Hugo Serrano-Posada; Jonathan Noé Arredondo-López; Ilse Gómez-Ramírez; Guillermo Fernández-Taboada; Lourival D. Possani; Gerardo Alfonso Anguiano-Vega; Lidia Riaño-Umbarila; Baltazar Becerril. Broadening the neutralizing capacity of a family of antibody fragments against different toxins from Mexican scorpions. Toxicon 2016, 119, 52 -63.

AMA Style

Everardo Rodríguez, Timoteo Olamendi-Portugal, Hugo Serrano-Posada, Jonathan Noé Arredondo-López, Ilse Gómez-Ramírez, Guillermo Fernández-Taboada, Lourival D. Possani, Gerardo Alfonso Anguiano-Vega, Lidia Riaño-Umbarila, Baltazar Becerril. Broadening the neutralizing capacity of a family of antibody fragments against different toxins from Mexican scorpions. Toxicon. 2016; 119 ():52-63.

Chicago/Turabian Style

Everardo Rodríguez; Timoteo Olamendi-Portugal; Hugo Serrano-Posada; Jonathan Noé Arredondo-López; Ilse Gómez-Ramírez; Guillermo Fernández-Taboada; Lourival D. Possani; Gerardo Alfonso Anguiano-Vega; Lidia Riaño-Umbarila; Baltazar Becerril. 2016. "Broadening the neutralizing capacity of a family of antibody fragments against different toxins from Mexican scorpions." Toxicon 119, no. : 52-63.

Journal article
Published: 22 June 2016 in PeerJ
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Mutating residues has been a common task in order to study structural properties of the protein of interest. Here, we propose and validate a simple method that allows the identification of structural determinants; i.e., residues essential for preservation of the stability of global structure, regardless of the protein topology. This method evaluates all of the residues in a 3D structure of a given globular protein by ranking them according to their connectivity and movement restrictions without topology constraints. Our results matched up with sequence-based predictors that look up for intrinsically disordered segments, suggesting that protein disorder can also be described with the proposed methodology.

ACS Style

Oscar D. Luna-Martínez; Abraham Vidal-Limón; Miryam I. Villalba-Velázquez; Rosalba Sánchez-Alcalá; Ramón Garduño-Juárez; Vladimir N. Uversky; Baltazar Becerril. Simple approach for ranking structure determining residues. PeerJ 2016, 4, e2136 .

AMA Style

Oscar D. Luna-Martínez, Abraham Vidal-Limón, Miryam I. Villalba-Velázquez, Rosalba Sánchez-Alcalá, Ramón Garduño-Juárez, Vladimir N. Uversky, Baltazar Becerril. Simple approach for ranking structure determining residues. PeerJ. 2016; 4 ():e2136.

Chicago/Turabian Style

Oscar D. Luna-Martínez; Abraham Vidal-Limón; Miryam I. Villalba-Velázquez; Rosalba Sánchez-Alcalá; Ramón Garduño-Juárez; Vladimir N. Uversky; Baltazar Becerril. 2016. "Simple approach for ranking structure determining residues." PeerJ 4, no. : e2136.

Journal article
Published: 01 January 2016 in Journal of Biological Chemistry
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Nowadays, the trends in the research devoted to develop novel antidotes against scorpion stings have showed excellent results with the use of recombinant antibody fragments. The polyclonal character of commercial anti-venoms, obtained through the immunization of animals and which contain several neutralizing antibodies that recognize different epitopes on the toxins, guarantees the neutralization of the venoms. To avoid the use of animals we aimed to develop an equivalent recombinant anti-venom composed of a few neutralizing single chain antibody fragments (scFvs) that bind to two different epitopes on the scorpion toxins. In this study, we obtained scFv RU1 derived from scFv C1. RU1 showed a good capacity to neutralize the Cn2 toxin and whole venom of the scorpionCentruroides noxius. Previously, we had produced scFv LR, obtained from a different parental fragment (scFv 3F). LR also showed a similar neutralizing capacity. The simultaneous administration of both scFvs resulted in improved protection, which was translated as a rapid recovery of previously envenomed animals. The crystallographic structure of the ternary complex (scFv LR-Cn2-scFv RU1) allowed us to identify the areas of interaction of both scFvs with the toxin, which correspond to non-overlapping sites. The epitope recognized by scFv RU1 seems to be related to a greater efficiency in the neutralization of the whole venom. In addition, the structural analysis of the complex helped us to explain the cross-reactivity of these scFvs and how they neutralize the venom.

ACS Style

Lidia Riaño-Umbarila; Luis M. Ledezma-Candanoza; Hugo Serrano-Posada; Guillermo Fernández-Taboada; Timoteo Olamendi-Portugal; Sonia Rojas-Trejo; Ilse V. Gómez -Ramírez; Enrique Rudino-Pinera; Lourival D. Possani; Baltazar Becerril. Optimal Neutralization of Centruroides noxius Venom Is Understood through a Structural Complex between Two Antibody Fragments and the Cn2 Toxin. Journal of Biological Chemistry 2016, 291, 1619 -1630.

AMA Style

Lidia Riaño-Umbarila, Luis M. Ledezma-Candanoza, Hugo Serrano-Posada, Guillermo Fernández-Taboada, Timoteo Olamendi-Portugal, Sonia Rojas-Trejo, Ilse V. Gómez -Ramírez, Enrique Rudino-Pinera, Lourival D. Possani, Baltazar Becerril. Optimal Neutralization of Centruroides noxius Venom Is Understood through a Structural Complex between Two Antibody Fragments and the Cn2 Toxin. Journal of Biological Chemistry. 2016; 291 (4):1619-1630.

Chicago/Turabian Style

Lidia Riaño-Umbarila; Luis M. Ledezma-Candanoza; Hugo Serrano-Posada; Guillermo Fernández-Taboada; Timoteo Olamendi-Portugal; Sonia Rojas-Trejo; Ilse V. Gómez -Ramírez; Enrique Rudino-Pinera; Lourival D. Possani; Baltazar Becerril. 2016. "Optimal Neutralization of Centruroides noxius Venom Is Understood through a Structural Complex between Two Antibody Fragments and the Cn2 Toxin." Journal of Biological Chemistry 291, no. 4: 1619-1630.

Journal article
Published: 01 January 2015 in Journal of Biological Chemistry
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Light chain amyloidosis (AL) is a disease which affects vital organs by the fibrillar aggregation of monoclonal light chains. λ3r germ line is significantly implicated in this disease. In this work, we contrasted the thermodynamic stability and aggregation propensity of 3mJL2 (non amyloidogenic) and 3rJL2 (amyloidogenic) λ3 germ lines. Due to an inherent limitation (extremely low expression), Cys at position 34 of the 3r germ-line, was replaced by Tyr reaching a good expression yield. A second substitution (W91A), was introduced in 3r in order to obtain a better template to incorporate additional mutations. Although the single mutant (C34Y) was not fibrillogenic, the second mutation located at CDR3 (W91A), induced fibrillogenesis. We propose, for the first time, that CDR3 (position 91) affects the stability and fiber formation of human λ3r light chains. Using the double mutant (3rJL2/YA) as template, other variants were constructed in order to evaluate the importance of those substitutions into the stability and aggregation propensity of λ3 light chains. A change in position 7 (P7D), boosted 3rJL2/YA fibrillogenic properties. Modification of position 48 (I48M) partially reverted 3rJL2/YA fibril aggregation. Finally, changes at positions 8 (P8S) or 40 (P40S) completely reverted fibril formation. These results confirm the influential roles of N-terminal region (positions 7 and 8) and the loop 40-60 (positions 40 and 48) on (AL) amyloidosis. X-ray crystallography revealed that the three-dimensional topology of the single and double λ3r mutants was not significantly altered. This mutagenic approach, helped to identify key regions implicated in λ3 (AL) amyloidosis.

ACS Style

Miryam Ivette Villalba; Juan Carlos Canul Tec; Oscar Daniel Luna-Martinez; Rosalba Sánchez-Alcalá; Timoteo Olamendi-Portugal; Enrique Rudino-Pinera; Sonia Rojas; Rosana Sanchez-Lopez; Daniel Alejandro Fernandez-Velasco; Baltazar Becerril. Site-directed Mutagenesis Reveals Regions Implicated in the Stability and Fiber Formation of Human λ3r Light Chains. Journal of Biological Chemistry 2015, 290, 2577 -2592.

AMA Style

Miryam Ivette Villalba, Juan Carlos Canul Tec, Oscar Daniel Luna-Martinez, Rosalba Sánchez-Alcalá, Timoteo Olamendi-Portugal, Enrique Rudino-Pinera, Sonia Rojas, Rosana Sanchez-Lopez, Daniel Alejandro Fernandez-Velasco, Baltazar Becerril. Site-directed Mutagenesis Reveals Regions Implicated in the Stability and Fiber Formation of Human λ3r Light Chains. Journal of Biological Chemistry. 2015; 290 (5):2577-2592.

Chicago/Turabian Style

Miryam Ivette Villalba; Juan Carlos Canul Tec; Oscar Daniel Luna-Martinez; Rosalba Sánchez-Alcalá; Timoteo Olamendi-Portugal; Enrique Rudino-Pinera; Sonia Rojas; Rosana Sanchez-Lopez; Daniel Alejandro Fernandez-Velasco; Baltazar Becerril. 2015. "Site-directed Mutagenesis Reveals Regions Implicated in the Stability and Fiber Formation of Human λ3r Light Chains." Journal of Biological Chemistry 290, no. 5: 2577-2592.

Book chapter
Published: 24 December 2014 in Scorpion Venoms
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The detailed knowledge of the medically important components within the venoms from poisonous animals has prompted the rational generation of improved antivenoms. The new generation of antivenoms, in the case of scorpion envenoming, will be based on the neutralization of the toxins directed against mammalian ion channels, specifically sodium channels. The neutralization of the major toxic molecules declines the lethality of the whole venom. The next generation of antivenoms will depend substantially on the advancements in the field of antibody engineering. The accumulation of detailed information of antibody structure and function proposes that human recombinant antibodies in combination with phage display and directed evolution as a powerful in vitro biotechnological platform alternative to classical antivenoms or monoclonal antibodies for the generation of outstanding therapeutic antibodies. This biotechnological platform has allowed the isolation of safe and efficient recombinant neutralizing antibodies. Many antibody fragments generated using this platform bear exceptional properties that had not been reached using classical approaches. This review describes the great progress that has been achieved on the improvement of antivenoms against scorpion envenoming which have been generated using the already mentioned platform as compared with classical and/or hybridoma approaches.

ACS Style

Everardo Remi Rodríguez Rodríguez; Lidia Riaño Umbarila; Lourival D. Possani; Baltazar Becerril. Recombinant Neutralizing Antibodies, A New Generation of Antivenoms. Scorpion Venoms 2014, 139 -159.

AMA Style

Everardo Remi Rodríguez Rodríguez, Lidia Riaño Umbarila, Lourival D. Possani, Baltazar Becerril. Recombinant Neutralizing Antibodies, A New Generation of Antivenoms. Scorpion Venoms. 2014; ():139-159.

Chicago/Turabian Style

Everardo Remi Rodríguez Rodríguez; Lidia Riaño Umbarila; Lourival D. Possani; Baltazar Becerril. 2014. "Recombinant Neutralizing Antibodies, A New Generation of Antivenoms." Scorpion Venoms , no. : 139-159.

Journal article
Published: 01 December 2013 in Toxicon
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Using phage display and directed evolution, our group has progressed in the construction of a second family of human single chain variable fragments (scFv) which bind to scorpion toxins dangerous to mammals. It was observed that scFv C1 only bound initially to toxin Cn2, which constitutes 6.8% of whole venom from the scorpion Centruroides noxius Hoffman. Only a few amino acid changes were necessary to extend its recognition to other similar toxins and without affecting the recognition for its primary antigen (Cn2 toxin). One variant of scFv C1 (scFv 202F) was selected after two cycles of directed evolution against Cll1 toxin, the second major toxic component from the venom of the Mexican scorpion Centruroides limpidus limpidus Karsh (0.5% of the whole venom). scFv 202F is also capable of recognizing Cn2 toxin. Despite not having the highest affinity for toxins Cll1 (KD = 25.1 × 10(-9) M) or Cn2 (KD = 8.1 × 10(-9) M), this antibody fragment neutralized one LD50 of each one of these toxins. Additionally, scFv 202F moderately recognized Cll2 toxin which constitutes 1.5% of the venom from C. limpidus. Based on our previous experience, we consider that these results are promising; consequently, we continue working on generating new optimized variants from scFv C1 that could be part of a recombinant scorpion anti-venom from human origin, that might reach the market in the near future.

ACS Style

Lidia Riaño-Umbarila; Timoteo Olamendi-Portugal; Citlalli Morelos-Juárez; Georgina B. Gurrola; Lourival D. Possani; Baltazar Becerril. A novel human recombinant antibody fragment capable of neutralizing Mexican scorpion toxins. Toxicon 2013, 76, 370 -376.

AMA Style

Lidia Riaño-Umbarila, Timoteo Olamendi-Portugal, Citlalli Morelos-Juárez, Georgina B. Gurrola, Lourival D. Possani, Baltazar Becerril. A novel human recombinant antibody fragment capable of neutralizing Mexican scorpion toxins. Toxicon. 2013; 76 ():370-376.

Chicago/Turabian Style

Lidia Riaño-Umbarila; Timoteo Olamendi-Portugal; Citlalli Morelos-Juárez; Georgina B. Gurrola; Lourival D. Possani; Baltazar Becerril. 2013. "A novel human recombinant antibody fragment capable of neutralizing Mexican scorpion toxins." Toxicon 76, no. : 370-376.

Journal article
Published: 01 March 2013 in Peptides
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Peptide de13a was previously purified from the venom of the worm-hunting cone snail Conus delessertii from the Yucatán Channel, México. This peptide has eight cysteine (Cys) residues in the unique arrangement C-C-C-CC-C-C-C, which defines the cysteine framework XIII ("-" represents one or more non-Cys residues). Remarkably, δ-hydroxy-lysine residues have been found only in conotoxin de13a, which also contains an unusually high proportion of hydroxylated amino acid residues. Here, we report the cDNA cloning of the complete precursor De13.1 of a related peptide, de13b, which has the same Cys framework and inter-Cys spacings as peptide de13a, and shares high protein/nucleic acid sequence identity (87%/90%) with de13a, suggesting that both peptides belong to the same conotoxin gene superfamily. Analysis of the signal peptide of precursor De13.1 reveals that this precursor belongs to a novel conotoxin gene superfamily that we chose to name gene superfamily G. Thus far superfamily G only includes two peptides, each of which contains the same, distinctive Cys framework and a high proportion of amino acid residues with hydroxylated side chains.

ACS Style

Manuel B. Aguilar; Ernesto Ortiz; Quentin Kaas; Estuardo Lopez Vera; Baltazar Becerril; Lourival D. Possani; Edgar P. Heimer de la Cotera. Precursor De13.1 from Conus delessertii defines the novel G gene superfamily. Peptides 2013, 41, 17 -20.

AMA Style

Manuel B. Aguilar, Ernesto Ortiz, Quentin Kaas, Estuardo Lopez Vera, Baltazar Becerril, Lourival D. Possani, Edgar P. Heimer de la Cotera. Precursor De13.1 from Conus delessertii defines the novel G gene superfamily. Peptides. 2013; 41 ():17-20.

Chicago/Turabian Style

Manuel B. Aguilar; Ernesto Ortiz; Quentin Kaas; Estuardo Lopez Vera; Baltazar Becerril; Lourival D. Possani; Edgar P. Heimer de la Cotera. 2013. "Precursor De13.1 from Conus delessertii defines the novel G gene superfamily." Peptides 41, no. : 17-20.

Book chapter
Published: 01 January 2013 in Toxins and Drug Discovery
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The detailed knowledge of the medically important components within the venoms from poisonous animals has prompted the rational generation of improved antivenoms. The new generation of antivenoms, in the case of scorpion envenoming, will be based on the neutralization of the toxins directed against mammalian ion channels, specifically sodium channels. The neutralization of the major toxic molecules declines the lethality of the whole venom. The next generation of antivenoms will depend substantially on the advancements in the field of antibody engineering. The accumulation of detailed information of antibody structure and function proposes that human recombinant antibodies in combination with phage display and directed evolution as a powerful in vitro biotechnological platform alternative to classical antivenoms or monoclonal antibodies for the generation of outstanding therapeutic antibodies. This biotechnological platform has allowed the isolation of safety and efficient recombinant neutralizing antibodies. Many antibody fragments generated using this platform bear exceptional properties that had not been reached using classical approaches. This review describes the great progress that has been achieved on the improvement of antivenoms against scorpion envenoming which have been generated using the already mentioned platform as compared with classical and/or hybridoma approaches.

ACS Style

Everardo Remi Rodríguez Rodríguez; Lidia Riaño Umbarila; Lourival D. Possani; Dr. Baltazar Becerril. Recombinant Neutralizing Antibodies, A New Generation of Antivenoms. Toxins and Drug Discovery 2013, 1 -19.

AMA Style

Everardo Remi Rodríguez Rodríguez, Lidia Riaño Umbarila, Lourival D. Possani, Dr. Baltazar Becerril. Recombinant Neutralizing Antibodies, A New Generation of Antivenoms. Toxins and Drug Discovery. 2013; ():1-19.

Chicago/Turabian Style

Everardo Remi Rodríguez Rodríguez; Lidia Riaño Umbarila; Lourival D. Possani; Dr. Baltazar Becerril. 2013. "Recombinant Neutralizing Antibodies, A New Generation of Antivenoms." Toxins and Drug Discovery , no. : 1-19.

Journal article
Published: 01 August 2012 in Toxicon
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ACS Style

Baltazar Becerril; Lidia Riaño; Lourival D. Possani. 184. Development of Novel Scorpion Anti-Venoms in México. Toxicon 2012, 60, 190 .

AMA Style

Baltazar Becerril, Lidia Riaño, Lourival D. Possani. 184. Development of Novel Scorpion Anti-Venoms in México. Toxicon. 2012; 60 (2):190.

Chicago/Turabian Style

Baltazar Becerril; Lidia Riaño; Lourival D. Possani. 2012. "184. Development of Novel Scorpion Anti-Venoms in México." Toxicon 60, no. 2: 190.

Journal article
Published: 01 April 2012 in Immunology Letters
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The single-chain antibody fragment (scFv) 6009F, obtained by directed evolution, neutralizes the effects of the Cn2 toxin, which is the major toxic component of Centruroides noxius scorpion venom. In this work we compared the neutralization capacity and the thermodynamic stability of scFv 6009F with those of two other derived formats: Fab 6009F and diabody 6009F. Additionally, the affinity constants to Cn2 toxin of the three recombinant antibody fragments were determined by means of BIAcore. We found a correlation between the thermodynamic stability of these antibody fragments with their neutralization capacity. The order of thermodynamic stability determined was Fab≫scFv>diabody. The Fab and scFv were capable of neutralizing the toxic effects of Cn2 and whole venom but the diabody was unable to fully neutralize intoxication. In silico analysis of the diabody format indicates that the reduction of stability and neutralization capacity could be explained by a less cooperative interface between the heavy and the light variable domains.

ACS Style

Verónica Quintero-Hernández; Luis Del Pozo-Yauner; Martha Pedraza-Escalona; Victor R. Juárez-González; Israel Alcántara-Recillas; Lourival D. Possani; Baltazar Becerril. Evaluation of three different formats of a neutralizing single chain human antibody against toxin Cn2: Neutralization capacity versus thermodynamic stability. Immunology Letters 2012, 143, 152 -160.

AMA Style

Verónica Quintero-Hernández, Luis Del Pozo-Yauner, Martha Pedraza-Escalona, Victor R. Juárez-González, Israel Alcántara-Recillas, Lourival D. Possani, Baltazar Becerril. Evaluation of three different formats of a neutralizing single chain human antibody against toxin Cn2: Neutralization capacity versus thermodynamic stability. Immunology Letters. 2012; 143 (2):152-160.

Chicago/Turabian Style

Verónica Quintero-Hernández; Luis Del Pozo-Yauner; Martha Pedraza-Escalona; Victor R. Juárez-González; Israel Alcántara-Recillas; Lourival D. Possani; Baltazar Becerril. 2012. "Evaluation of three different formats of a neutralizing single chain human antibody against toxin Cn2: Neutralization capacity versus thermodynamic stability." Immunology Letters 143, no. 2: 152-160.

Journal article
Published: 01 April 2012 in Peptides
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From the cDNA libraries made from the venom glands of two scorpions belonging to the Vaejovidae family, four different putative non disulfide-bridged antimicrobial peptides were identified: VmCT1 and VmCT2 from Vaejovis mexicanus smithi plus VsCT1 and VsCT2 from Vaejovis subcristatus. These short peptides (with only 13 amino acid residues each) share important amino acid sequence similarities among themselves and with other reported antimicrobial peptides, but their biological activities vary dramatically. This communication reports the cloning, chemical synthesis and characterization of these peptides. Two peptides, VmCT1 and VmCT2 showed broad-spectrum antibacterial activity with minimum inhibitory concentrations MICs in the range of 5-25 μM and 10-20 μM respectively, whereas their hemolytic activity at these concentrations was low. Structure-function relationships that might determine the differences in activities are discussed.

ACS Style

Santos Ramírez; Verónica Quintero-Hernández; Juana María Jiménez-Vargas; Gerardo Corzo; Lourival D. Possani; Baltazar Becerril; Ernesto Ortiz. Gene cloning and functional characterization of four novel antimicrobial-like peptides from scorpions of the family Vaejovidae. Peptides 2012, 34, 290 -295.

AMA Style

Santos Ramírez, Verónica Quintero-Hernández, Juana María Jiménez-Vargas, Gerardo Corzo, Lourival D. Possani, Baltazar Becerril, Ernesto Ortiz. Gene cloning and functional characterization of four novel antimicrobial-like peptides from scorpions of the family Vaejovidae. Peptides. 2012; 34 (2):290-295.

Chicago/Turabian Style

Santos Ramírez; Verónica Quintero-Hernández; Juana María Jiménez-Vargas; Gerardo Corzo; Lourival D. Possani; Baltazar Becerril; Ernesto Ortiz. 2012. "Gene cloning and functional characterization of four novel antimicrobial-like peptides from scorpions of the family Vaejovidae." Peptides 34, no. 2: 290-295.

Journal article
Published: 01 February 2011 in Journal of Biological Chemistry
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We report the optimization of a family of human single chain antibody fragments (scFv) for neutralizing two scorpion venoms. The parental scFv 3F recognizes the main toxins of Centruroides noxius Hoffmann (Cn2) and Centruroides suffusus suffusus (Css2), albeit with low affinity. This scFv was subjected to independent processes of directed evolution to improve its recognition toward Cn2 (Riaño-Umbarila, L., Juárez-González, V. R., Olamendi-Portugal, T., Ortíz-León, M., Possani, L. D., and Becerril, B. (2005) FEBS J. 272, 2591-2601) and Css2 (this work). Each evolved variant showed strong cross-reactivity against several toxins, and was capable of neutralizing Cn2 and Css2. Furthermore, each variant neutralized the whole venoms of the above species. As far as we know, this is the first report of antibodies with such characteristics. Maturation processes revealed key residue changes to attain expression, stability, and affinity improvements as compared with the parental scFv. Combination of these changes resulted in the scFv LR, which is capable of rescuing mice from severe envenomation by 3 LD(50) of freshly prepared whole venom of C. noxius (7.5 μg/20 g of mouse) and C. suffusus (26.25 μg/20 g of mouse), with surviving rates between 90 and 100%. Our research is leading to the formulation of an antivenom consisting of a discrete number of human scFvs endowed with strong cross-reactivity and low immunogenicity.

ACS Style

Lidia Riaño-Umbarila; Gabriel Contreras-Ferrat; Timoteo Olamendi-Portugal; Citlalli Morelos-Juárez; Gerardo Corzo; Lourival D. Possani; Baltazar Becerril. Exploiting Cross-reactivity to Neutralize Two Different Scorpion Venoms with One Single Chain Antibody Fragment. Journal of Biological Chemistry 2011, 286, 6143 -6151.

AMA Style

Lidia Riaño-Umbarila, Gabriel Contreras-Ferrat, Timoteo Olamendi-Portugal, Citlalli Morelos-Juárez, Gerardo Corzo, Lourival D. Possani, Baltazar Becerril. Exploiting Cross-reactivity to Neutralize Two Different Scorpion Venoms with One Single Chain Antibody Fragment. Journal of Biological Chemistry. 2011; 286 (8):6143-6151.

Chicago/Turabian Style

Lidia Riaño-Umbarila; Gabriel Contreras-Ferrat; Timoteo Olamendi-Portugal; Citlalli Morelos-Juárez; Gerardo Corzo; Lourival D. Possani; Baltazar Becerril. 2011. "Exploiting Cross-reactivity to Neutralize Two Different Scorpion Venoms with One Single Chain Antibody Fragment." Journal of Biological Chemistry 286, no. 8: 6143-6151.

Research article
Published: 07 February 2008 in Proteins: Structure, Function, and Bioinformatics
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Light chain‐associated amyloidosis is a fatal disease characterized by the aggregation and pathologic deposition of monoclonal light chain‐related fragments as amyloid fibrils in organs or tissues throughout the body. Notably, it has been observed that proteins encoded by the λ variable light chain (VL) gene segment 6a are invariably associated with amyloid deposition; however, the contribution of the gene to this phenomenon has not been established. In this regard, we have determined the thermodynamic stability and kinetics of in vitro fibrillogenesis of a recombinant (r) VL protein, designated 6aJL2, which contains the predicted sequences encoded by the 6a and JL2 germline genes. Additionally, we studied a 6a mutant (6aJL2‐Arg25Gly), that is present in ∼25% of all amyloid‐associated λ6 light chains. Remarkably, the wild‐type 6aJL2 protein was more stable than were all known amyloidogenic κ and λ light chains for which stability parameters are available; more importantly, it was even more so (and less fibrillogenic) than the only clinically proven nonamyloidogenic λ6 protein, Jto. Conversely, the mutated 6aJL2‐R25G molecule was considerably less stable and more fibrillogenic than was the native 6aJL2. Our data indicate that the propensity of λ6 light chains to form amyloid can not be attributed to thermodynamic instability of the germline‐encoded Vλ6 domain, but rather, is dependent on sequence alterations that render such proteins amyloidogenic. Proteins 2008.

ACS Style

Luis DEL Pozo-Yauner; Ernesto Ortiz; Rosalba Sánchez; Rosana Sanchez-Lopez; Leopoldo Güereca; Charles L. Murphy; Amy Allen; Jonathan Wall; D. Alejandro Fernández-Velasco; Alan Solomon; Baltazar Becerril. Influence of the germline sequence on the thermodynamic stability and fibrillogenicity of human lambda 6 light chains. Proteins: Structure, Function, and Bioinformatics 2008, 72, 684 -692.

AMA Style

Luis DEL Pozo-Yauner, Ernesto Ortiz, Rosalba Sánchez, Rosana Sanchez-Lopez, Leopoldo Güereca, Charles L. Murphy, Amy Allen, Jonathan Wall, D. Alejandro Fernández-Velasco, Alan Solomon, Baltazar Becerril. Influence of the germline sequence on the thermodynamic stability and fibrillogenicity of human lambda 6 light chains. Proteins: Structure, Function, and Bioinformatics. 2008; 72 (2):684-692.

Chicago/Turabian Style

Luis DEL Pozo-Yauner; Ernesto Ortiz; Rosalba Sánchez; Rosana Sanchez-Lopez; Leopoldo Güereca; Charles L. Murphy; Amy Allen; Jonathan Wall; D. Alejandro Fernández-Velasco; Alan Solomon; Baltazar Becerril. 2008. "Influence of the germline sequence on the thermodynamic stability and fibrillogenicity of human lambda 6 light chains." Proteins: Structure, Function, and Bioinformatics 72, no. 2: 684-692.