[Computer analysis of the spatial structure of the amphotericin channel].

Energy of Amphotericin B cholesterol complex in a membrane was calculated by the method of atom--atomic potentials. The complex is shown to have two stable states. One of them is stabilized by electrostatic interactions between charged groups of neighbouring antibiotic molecules due to a decline of the molecules to the pore radius.

[Calculation of the structure of the serotonin-antibiotic lasalocid A complex by conformation analysis and the Monte Carlo method].

The conformational aspects of interaction of the antibiotic X537A at complexation with serotonin, hydration of molecules and their complex were studied by the methods of theoretical conformational analysis and Monte-Carlo.

[Contribution of individual structural components to stabilization of the secondary structure of double-helical polynucleotides].

Contributions of individual structural components of the double-helical polynucleotide to the stabilization of its secondary structure have been studied. The energy of intramolecular interactions was calculated by the method of atom-atom potentials. Sections of the energy function were constructed according to the parameters determining mutual location of base pairs with the optimal conformation of ribose-phosphate backbone in the points close to A- and B-forms of DNA.

[Theoretical conformational analysis of doulble-stranded polynucleotides].

Calculations of intramolecular interaction energy of two-stranded helical homopolynucleotide in the function of nine conformational variables have been carried out by the method of atom-atom potential functions. Four of these variables determine mutual position of base pairs, other four--deoxiribose ring conformation and other one--orientation of this ring with respect to the base. For this purpose an algorythm connecting dependent variables with independent ones has been developed.

[The influence of complementary base pair interactions on secondary structure formation and conformational transitions in polynucleotides].

The calculations have been carried out of interaction energy between complementary base pairs of nucleic acids in the function of conformational parametres of double helix (Arnott's parameters) by the method of atom-atom potential functions. Interaction energy as a function of conformational parametres is valley-like and varies little along the bottom of the valley. The regions of interaction energy minima are compared with experimentally determined conformational parametres of nucleic acid double helices.

[Semiempirical calculation of the relation of the interaction energy between complementary pairs of nitrogenous bases to nucleic acid conformational parameters].

The calculations of interaction energy between complementary base pairs of nucleic acids in the function of 5 variables determining parameters of double helix (Arnott's parameters) have been carried out by the method of atom-atom potential functions. Four of these parameters are essential in the case of mutual positions of bases corresponding to conformational A-family, and only two parameters (the distance between pairs along helical axis and the angle of rotation around this axis)--in the case of B-family. Positions of the interaction energy minima over each of the essential variables are close to experimentally determined parameters.