TOPOLOGICAL-STRUCTURE OF THE GENETIC-CODE

On the basis of the topological concept of the vicinity of the point, graphs of connectedness for four nitrous bases (L and D tetrahedra) an d the topological patterns of doublet and triplet genetic codes were c onstructed. These topological patterns were isomorphic to Boolean hype rcubes B-4 and B-6, respectively. The resultant structures of the gene tic code resembled those obtained earlier in terms of the rhombic vari ant of the genetic code table, which was constructed on the basis of c omplementarity of the coding doublets. Specifically, both models assum ed the following: (1) when two groups of doublets and quartets of trip lets that coded for one amino acid or two amino acids each were transf ormed into each other according to Rumer's rule (C <--> A, G <--> U), they retained C-2 symmetry, and (2) single transitions of nitrous base s changed the structures of the encoded amino acids to the minimum pos sible extent. A possible mechanism for the origin of the genetic code and the possibility of using the characteristics of the obtained struc tures to develop the algorithm of prediction of the supermolecular pro tein structure, read genetic ''texts,'' and refine the functions of am ino acids as molecular modules are discussed in terms of the results o btained.