[Effect of spatial coupling of amino acid residues on the possibility of mutational substitution in globular proteins].

Amino acid residues can be divided into similar groups by frequencies of interreplacements in the evolutionary pathway and by trends to spatial contacts at the tertiary structures of globular proteins. Each residue was compared to the cluster of spatial surrounding--the totality of residues spacially drawn together. 5210 clusters in 32 unhomologous proteins with established tertiary structure and 6447 clusters formed only by variables amino acid residues were analysed. Spatial contacts among residues were studied depending on the secondary structure and the amount of residues in a cluster. It was assumed that functionally admissible mutations may be defined, first of all, by the degree of neighboring of amino acid residues in the spatial surrounding.