V.K. Antonov

Bio: V.K. Antonov is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Cyclol & Biological membrane. The author has an hindex of 8, co-authored 18 publications receiving 496 citations.

Cyclodepsipeptides as chemical tools for studying ionic transport through membranes

Abstract: This paper reports a study of the chemistry of valinomycin, enniatins and related membrane-active depsipeptides that increase alkali metal ion permeability of model and biological membranes. The antimicrobial activity of these compounds and their effect on membranes has been correlated with their cation-complexing ability. The complexing reaction has been studied by spectropolarimetric and conductimetric methods. Nuclear magnetic resonance, optical rotatory dispersion, and infrared spectrophotometric studies have revealed the coexistence of conformers of the cyclodepsipeptides in solution and have led to elucidation of the spatial structure of valinomycin, enniatin B and their K+ complexes. The effect of the conformational properties of the cyclodepsipeptides on their complexation efficiency and selectivity, surface-active properties and behavior towards phospholipid monolayers, bimolecular phospholipid membranes and a number of biological membrane systems has been ascertained. The studies have clearly shown the feasibility of using cyclodepsipeptides with predetermined structural and conformational parameters as chemical tools for membrane studies. it is suggested that the principle of conformation-dependent cation binding through iondipole interactions may possibly lie at the basis of the mode of action of systems governing the natural ion permeability in biological membranes.

Phase transitions and fluidity characteristics of lipids and cell membranes.

Abstract: The concept that the liquid crystalline or mesomorphic condition was of importance to biological systems is a relatively old idea. Thus Bernal (1933) when discussing the different types of arrangements of molecules in liquid crystals commented ‘Such structures belong to the liquid crystal as a unit and not to its molecules which may be replaced by others without destroying them and they persist in spite of the complete fluidity of the substance. These are just the properties to be required for a degree of organization between that of the continuous substance, liquid or crystalline solid and even the simplest living cell.’ Stewart (1961) some thirty years later also stated that ‘It is this property – the combination of flow and lability with a preferred and relatively stable molecular orientation – that makes the mesomorphic (i.e. liquid crystal) phase uniquely appropriate to the structure of protoplasm and living tissue.’

Design of organic complexing agents Strategies towards properties

Abstract: Looking back to the introductory section, it appears that in recent years appreciable progress has been made in understanding and controlling the process of spherical recognition of alkali and alkaline-earth cations by organic ligand molecules. Information stored in various structural features allows the thermodynamic and kinetic features of the complexation process to be monitored. Further progress may be achieved by making use of the feedback from present results to adjust and improve the model and to analyze the information-property relationship.