A synergetic law, being of common physicochemical and biological sense, is formulated: any evolving system that possesses an excess of free energy and elements with chiral asymmetry, while being...
A systemic regularity of molecular biology is considered: the tendency towards alternating of the sense of chirality of intramolecular structural levels of DNA and proteins, namely, D–L–D–L for DNA and L–D–L–D for proteins, is observable starting from the level of asymmetric carbon in deoxyribose and amino acids. Helicity is a special case of chirality. In intermolecular interactions, the sense of chirality of the highest intramolecular structural level directly involved in the interaction prevails in each of the participants. The interaction of molecules of the same nature (protein–protein, DNA–RNA, tRNA–mRNA, and ribozymes) mainly occurs in the case of the same sense of chirality, either L–L or D–D, and for molecules of different types (DNA–protein, tRNA–amino acids, and enzyme–substrate), in the case of different senses of chirality, either D–L or L–D. An alternating sense of the chiral hierarchy of conjugated levels of macromolecular structures in proteins and nucleic acids is of general biological importance: it determines the discreteness of levels, serves as a tool of folding, and provides a structural basis for “preferred collective” (or “macroscopic mechanical”) degrees of freedom in the design of macromolecular machines, as well as being one of the mechanisms of blockwise/saltatory development of the evolutionary process. A new fundamental concept is proposed: the homochirality of primary structures of DNA and proteins determines the amount of the entropic component of the free energy, which is used in the processes of folding and molecular rearrangements.
The origin of chiral asymmetry in biology has attracted the attention of the research community throughout the years. In this paper we discuss the role of chirality and chirality sign alternation (L–D–L–D in proteins and D–L–D–L in DNA) in promoting self-organization in biology, starting at the level of single molecules and continuing to the level of supramolecular assemblies. In addition, we also discuss chiral assemblies in solutions of homochiral organic molecules. Sign-alternating chiral hierarchies created by proteins and nucleic acids are suggested to create the structural basis for the existence of selected mechanical degrees of freedom required for conformational dynamics in enzymes and macromolecular machines.
The structures and properties of the diphenylalanine (FF) peptide nanotubes (PNTs), both L-chiral and D-chiral (L-FF and D-FF) and empty and filled with water/ice clusters, are presented and analyzed. DFT (VASP) and semi-empirical calculations (HyperChem) to study these structural and physical properties of PNTs (including ferroelectric) were used. The results obtained show that after optimization the dipole moment and polarization of both chiral type L-FF and D-FF PNT and embedded water/ice cluster are enhanced; the water/ice cluster acquire the helix-like structure similar as L-FF and D-FF PNT. Ferroelectric properties of tubular water/ice helix-like cluster, obtained after optimization inside L-FF and D-FF PNT, as well of the total L-FF and D-FF PNT with embedded water/ice cluster, are discussed.
1 November 2017 in Journal of Water Chemistry and Technology
The existence of stable formations representing submillimeter density inhomogeneities in aqueous solutions was confirmed by using the laser light diffraction (LALLS) method and also the dynamic (DLS)