This page has only limited features, please log in for full access.
We recently discovered an anti-ferroptotic mechanism inherent to M1 macrophages whereby high levels of NO● suppressed ferroptosis via inhibition of hydroperoxy-eicosatetraenoyl-phosphatidylethanolamine (HpETE-PE) production by 15-lipoxygenase (15LOX) complexed with PE-binding protein 1 (PEBP1). However, the mechanism of NO● interference with 15LOX/PEBP1 activity remained unclear. Here, we use a biochemical model of recombinant 15LOX-2 complexed with PEBP1, LC-MS redox lipidomics, and structure-based modeling and simulations to uncover the mechanism through which NO● suppresses ETE-PE oxidation. Our study reveals that O2 and NO● use the same entry pores and channels connecting to 15LOX-2 catalytic site, resulting in a competition for the catalytic site. We identified residues that direct O2 and NO● to the catalytic site, as well as those stabilizing the esterified ETE-PE phospholipid tail. The functional significance of these residues is supported by in silico saturation mutagenesis. We detected nitrosylated PE species in a biochemical system consisting of 15LOX-2/PEBP1 and NO● donor and in RAW264.7 M2 macrophages treated with ferroptosis-inducer RSL3 in the presence of NO●, in further support of the ability of NO● to diffuse to, and react at, the 15LOX-2 catalytic site. The results provide first insights into the molecular mechanism of repression of the ferroptotic Hp-ETE-PE production by NO●.
Karolina Mikulska-Ruminska; Tamil Anthonymuthu; Anastasia Levkina; Indira Shrivastava; Alexandr Kapralov; Hülya Bayır; Valerian Kagan; Ivet Bahar. NO● Represses the Oxygenation of Arachidonoyl PE by 15LOX/PEBP1: Mechanism and Role in Ferroptosis. International Journal of Molecular Sciences 2021, 22, 5253 .
AMA StyleKarolina Mikulska-Ruminska, Tamil Anthonymuthu, Anastasia Levkina, Indira Shrivastava, Alexandr Kapralov, Hülya Bayır, Valerian Kagan, Ivet Bahar. NO● Represses the Oxygenation of Arachidonoyl PE by 15LOX/PEBP1: Mechanism and Role in Ferroptosis. International Journal of Molecular Sciences. 2021; 22 (10):5253.
Chicago/Turabian StyleKarolina Mikulska-Ruminska; Tamil Anthonymuthu; Anastasia Levkina; Indira Shrivastava; Alexandr Kapralov; Hülya Bayır; Valerian Kagan; Ivet Bahar. 2021. "NO● Represses the Oxygenation of Arachidonoyl PE by 15LOX/PEBP1: Mechanism and Role in Ferroptosis." International Journal of Molecular Sciences 22, no. 10: 5253.
Cardiotoxin CTII from Naja oxiana cobra venom translocates to the intermembrane space (IMS) of mitochondria to disrupt the structure and function of the inner mitochondrial membrane. At low concentrations, CTII facilitates ATP-synthase activity, presumably via the formation of non-bilayer, immobilized phospholipids that are critical in modulating ATP-synthase activity. In this study, we investigated the effects of another cardiotoxin CTI from Naja oxiana cobra venom on the structure of mitochondrial membranes and on mitochondrial-derived ATP synthesis. By employing robust biophysical methods including 31P-NMR and 1H-NMR spectroscopy, we analyzed the effects of CTI and CTII on phospholipid packing and dynamics in model phosphatidylcholine (PC) membranes enriched with 2.5 and 5.0 mol% of cardiolipin (CL), a phospholipid composition that mimics that in the outer mitochondrial membrane (OMM). These experiments revealed that CTII converted a higher percentage of bilayer phospholipids to a non-bilayer and immobilized state and both cardiotoxins utilized CL and PC molecules to form non-bilayer structures. Furthermore, in order to gain further understanding on how cardiotoxins bind to mitochondrial membranes, we employed molecular dynamics (MD) and molecular docking simulations to investigate the molecular mechanisms by which CTII and CTI interactively bind with an in silico phospholipid membrane that models the composition similar to the OMM. In brief, MD studies suggest that CTII utilized the N-terminal region to embed the phospholipid bilayer more avidly in a horizontal orientation with respect to the lipid bilayer and thereby penetrate at a faster rate compared with CTI. Molecular dynamics along with the Autodock studies identified critical amino acid residues on the molecular surfaces of CTII and CTI that facilitated the long-range and short-range interactions of cardiotoxins with CL and PC. Based on our compiled data and our published findings, we provide a conceptual model that explains a molecular mechanism by which snake venom cardiotoxins, including CTI and CTII, interact with mitochondrial membranes to alter the mitochondrial membrane structure to either upregulate ATP-synthase activity or disrupt mitochondrial function.
Feng Li; Indira H. Shrivastava; Paul Hanlon; Ruben K. Dagda; Edward S. Gasanoff. Molecular Mechanism by which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane. Toxins 2020, 12, 425 .
AMA StyleFeng Li, Indira H. Shrivastava, Paul Hanlon, Ruben K. Dagda, Edward S. Gasanoff. Molecular Mechanism by which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane. Toxins. 2020; 12 (7):425.
Chicago/Turabian StyleFeng Li; Indira H. Shrivastava; Paul Hanlon; Ruben K. Dagda; Edward S. Gasanoff. 2020. "Molecular Mechanism by which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane." Toxins 12, no. 7: 425.
Cobra venom cardiotoxins (CVCs) can translocate to mitochondria to promote apoptosis by eliciting mitochondrial dysfunction. However, the molecular mechanism(s) by which CVCs are selectively targeted to the mitochondrion to disrupt mitochondrial function remains to be elucidated. By studying cardiotoxin from Naja mossambica mossambica cobra (cardiotoxin VII4), a basic three-fingered S-type cardiotoxin, we hypothesized that cardiotoxin VII4 binds to cardiolipin (CL) in mitochondria to alter mitochondrial structure/function and promote neurotoxicity. By performing confocal analysis, we observed that red-fluorescently tagged cardiotoxin rapidly translocates to mitochondria in mouse primary cortical neurons and in human SH-SY5Y neuroblastoma cells to promote aberrant mitochondrial fragmentation, a decline in oxidative phosphorylation, and decreased energy production. In addition, by employing electron paramagnetic resonance (EPR) and protein nuclear magnetic resonance (¹H-NMR) spectroscopy and phosphorescence quenching of erythrosine in model membranes, our compiled biophysical data show that cardiotoxin VII4 binds to anionic CL, but not to zwitterionic phosphatidylcholine (PC), to increase the permeability and formation of non-bilayer structures in CL-enriched membranes that biochemically mimic the outer and inner mitochondrial membranes. Finally, molecular dynamics simulations and in silico docking studies identified CL binding sites in cardiotoxin VII4 and revealed a molecular mechanism by which cardiotoxin VII4 interacts with CL and PC to bind and penetrate mitochondrial membranes.
Boris Zhang; Feng Li; Zhengyao Chen; Indira H. Shrivastava; Edward S. Gasanoff; Ruben K. Dagda. Naja mossambica mossambica Cobra Cardiotoxin Targets Mitochondria to Disrupt Mitochondrial Membrane Structure and Function. Toxins 2019, 11, 152 .
AMA StyleBoris Zhang, Feng Li, Zhengyao Chen, Indira H. Shrivastava, Edward S. Gasanoff, Ruben K. Dagda. Naja mossambica mossambica Cobra Cardiotoxin Targets Mitochondria to Disrupt Mitochondrial Membrane Structure and Function. Toxins. 2019; 11 (3):152.
Chicago/Turabian StyleBoris Zhang; Feng Li; Zhengyao Chen; Indira H. Shrivastava; Edward S. Gasanoff; Ruben K. Dagda. 2019. "Naja mossambica mossambica Cobra Cardiotoxin Targets Mitochondria to Disrupt Mitochondrial Membrane Structure and Function." Toxins 11, no. 3: 152.
Ferroptosis is a death program executed via selective oxidation of arachidonic acid–phosphatidylethanolamines (AA-PE) by 15-lipoxygenases. In mammalian cells and tissues, ferroptosis has been pathogenically associated with brain, kidney, and liver injury/diseases. We discovered that a prokaryotic bacterium, Pseudomonas aeruginosa, that does not contain AA-PE can express lipoxygenase (pLoxA), oxidize host AA-PE to 15-hydroperoxy-AA-PE (15-HOO-AA-PE), and trigger ferroptosis in human bronchial epithelial cells. Induction of ferroptosis by clinical P. aeruginosa isolates from patients with persistent lower respiratory tract infections was dependent on the level and enzymatic activity of pLoxA. Redox phospholipidomics revealed elevated levels of oxidized AA-PE in airway tissues from patients with cystic fibrosis (CF) but not with emphysema or CF without P. aeruginosa. We believe that the evolutionarily conserved mechanism of pLoxA-driven ferroptosis may represent a potential therapeutic target against P. aeruginosa–associated diseases such as CF and persistent lower respiratory tract infections.
Haider H. Dar; Yulia Tyurina; Karolina Mikulska-Ruminska; Indira Shrivastava; Hsiu-Chi Ting; Vladimir Tyurin; James Krieger; Claudette M. St. Croix; Simon Watkins; Erkan Bayir; Gaowei Mao; Catherine Armbruster; Alexandr Kapralov; Hong Wang; Matthew R. Parsek; Tamil S. Anthonymuthu; Abiola Ogunsola; Becca A. Flitter; Cody J. Freedman; Jordan R. Gaston; Theodore R. Holman; Joseph M. Pilewski; Joel S. Greenberger; Rama K. Mallampalli; Yohei Doi; Janet Lee; Ivet Bahar; Jennifer M. Bomberger; Hülya Bayır; Valerian E. Kagan. Pseudomonas aeruginosa utilizes host polyunsaturated phosphatidylethanolamines to trigger theft-ferroptosis in bronchial epithelium. Journal of Clinical Investigation 2018, 128, 4639 -4653.
AMA StyleHaider H. Dar, Yulia Tyurina, Karolina Mikulska-Ruminska, Indira Shrivastava, Hsiu-Chi Ting, Vladimir Tyurin, James Krieger, Claudette M. St. Croix, Simon Watkins, Erkan Bayir, Gaowei Mao, Catherine Armbruster, Alexandr Kapralov, Hong Wang, Matthew R. Parsek, Tamil S. Anthonymuthu, Abiola Ogunsola, Becca A. Flitter, Cody J. Freedman, Jordan R. Gaston, Theodore R. Holman, Joseph M. Pilewski, Joel S. Greenberger, Rama K. Mallampalli, Yohei Doi, Janet Lee, Ivet Bahar, Jennifer M. Bomberger, Hülya Bayır, Valerian E. Kagan. Pseudomonas aeruginosa utilizes host polyunsaturated phosphatidylethanolamines to trigger theft-ferroptosis in bronchial epithelium. Journal of Clinical Investigation. 2018; 128 (10):4639-4653.
Chicago/Turabian StyleHaider H. Dar; Yulia Tyurina; Karolina Mikulska-Ruminska; Indira Shrivastava; Hsiu-Chi Ting; Vladimir Tyurin; James Krieger; Claudette M. St. Croix; Simon Watkins; Erkan Bayir; Gaowei Mao; Catherine Armbruster; Alexandr Kapralov; Hong Wang; Matthew R. Parsek; Tamil S. Anthonymuthu; Abiola Ogunsola; Becca A. Flitter; Cody J. Freedman; Jordan R. Gaston; Theodore R. Holman; Joseph M. Pilewski; Joel S. Greenberger; Rama K. Mallampalli; Yohei Doi; Janet Lee; Ivet Bahar; Jennifer M. Bomberger; Hülya Bayır; Valerian E. Kagan. 2018. "Pseudomonas aeruginosa utilizes host polyunsaturated phosphatidylethanolamines to trigger theft-ferroptosis in bronchial epithelium." Journal of Clinical Investigation 128, no. 10: 4639-4653.
Binding of the viral spike drives cell entry and infection by HIV-1 to the cellular CD4 and chemokine receptors with associated conformational change of the viral glycoprotein envelope, gp120. Crystal structures of the CD4–gp120–antibody ternary complex reveal a large internal gp120 cavity formed by three domains—the inner domain, outer domain, and bridging sheet domain—and are capped by CD4 residue Phe43. Several structures of gp120 envelope in complex with various antibodies indicated that the bridging sheet adopts varied conformations. Here, we examine bridging sheet dynamics using a crystal structure of gp120 bound to the F105 antibody exhibiting an open bridging sheet conformation and with an added V3 loop. The two strands of the bridging sheet β2/β3 and β20/β21 are dissociated from each other and are directed away from the inner and outer domains. Analysis of molecular dynamics (MD) trajectories indicates that the β2/β3 and β20/β21 strands rapidly rearrange to interact with the V3 loop and the inner and outer domains, respectively. Residue N425 on β20 leads the conformational rearrangement of the β20/β21 strands by interacting with W112 on the inner domain and F382 on the outer domain. An accompanying shift is observed in the inner domain as helix α1 exhibits a loss in helicity and pivots away from helix α5. The two simulations provide a framework for understanding the conformational diversity of the bridging sheet and the propensity of the β20/β21 strand to refold between the inner and outer domains of gp120, in the absence of a bound ligand.
Indira H. Shrivastava; Kaylee Wendel; Judith M. LaLonde. Spontaneous Rearrangement of the β20/β21 Strands in Simulations of Unliganded HIV-1 Glycoprotein, gp120. Biochemistry 2012, 51, 7783 -7793.
AMA StyleIndira H. Shrivastava, Kaylee Wendel, Judith M. LaLonde. Spontaneous Rearrangement of the β20/β21 Strands in Simulations of Unliganded HIV-1 Glycoprotein, gp120. Biochemistry. 2012; 51 (39):7783-7793.
Chicago/Turabian StyleIndira H. Shrivastava; Kaylee Wendel; Judith M. LaLonde. 2012. "Spontaneous Rearrangement of the β20/β21 Strands in Simulations of Unliganded HIV-1 Glycoprotein, gp120." Biochemistry 51, no. 39: 7783-7793.
Human Immunodeficiency Virus (HIV) infection is initiated by binding of the viral glycoprotein gp120, to the cellular receptor CD4. On CD4 binding, gp120 undergoes conformational change, permitting binding to the chemokine receptor. Crystal structures of gp120 ternary complex reveal the CD4 bound conformation of gp120. We report here the application of the Gaussian network model (GNM) to the crystal structures of gp120 bound to CD4 or CD4 mimic and 17b, to study the collective motions of the gp120 core and determine the communication propensities of the residue network. The GNM fluctuation profiles identify residues in the inner domain and outer domain that may facilitate conformational change or stability, respectively. Communication propensities delineate a residue network that is topologically suited for signal propagation from the Phe43 cavity throughout the gp120 outer domain. These results provide a new context for interpreting gp120 core envelope structure–function relationships. Proteins 2010.
Indira Shrivastava; Judith M. LaLonde. Fluctuation dynamics analysis of gp120 envelope protein reveals a topologically based communication network. Proteins: Structure, Function, and Bioinformatics 2010, 78, 2935 -2949.
AMA StyleIndira Shrivastava, Judith M. LaLonde. Fluctuation dynamics analysis of gp120 envelope protein reveals a topologically based communication network. Proteins: Structure, Function, and Bioinformatics. 2010; 78 (14):2935-2949.
Chicago/Turabian StyleIndira Shrivastava; Judith M. LaLonde. 2010. "Fluctuation dynamics analysis of gp120 envelope protein reveals a topologically based communication network." Proteins: Structure, Function, and Bioinformatics 78, no. 14: 2935-2949.