[The 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) and the topological patterns of doublet and triplet genetic codes were constructed. These topological patterns were isomorphic to Boolean hypercubes B4 and B6, respectively. The resultant structures of the genetic code resembled those obtained earlier in terms of the rhombic variant of the genetic code table, which was constructed on the basis of complementarity of the coding doublets. Specifically, both models assumed the following: (1) when two groups of doublets and quartets of triplets that coded for one amino acid or two amino acids each were transformed into each other according to Rumer's rule (C <--> A, G <--> U), they retained C2 symmetry, and (2) single transitions of nitrous bases changed the structures of the encoded amino acids to the minimum possible extent. A possible mechanism for the origin of the genetic code and the possibility of using the characteristics of the obtained structures to develop the algorithm of prediction of the supermolecular protein structure, read genetic "texts", and refine the functions of amino acids as molecular modules are discussed in terms of the results obtained.