THE RATE OF MOLECULAR EVOLUTION OF MAMMALIAN SOLUBLE THIAMINE TRIPHOSPHATASE
A. F. Makarchikov
Grodno State Agricultural University, Belarus;
Institute of Pharmacology and Biochemistry, National Academy of Sciences of Belarus, Grodno, Belarus;
Thiamine triphosphate (ThTP) exists in various living cells – from bacteria to mammals. ThTP concentration in mammals is regulated by a specific soluble ThTPase, which has not been revealed experimentally, however, in other organisms. In NCBI and Ensembl databases we have found information about full-size or partial amino acid sequences of the enzyme from 38 mammal species. An average rate of amino acid substitutions (kaa) in ThTPase molecule was estimated from the data available to be 1.41·10-9 per site per year. This corresponds to unit evolutionary period of about 4.4 million years. The evolutionary rate varies for different portions of the enzyme, C-terminal fragment being the most variable (kaa?=?3.76·10-9; calculated only for 230 aa species?+ elephant). An average replacement rate of 1.95·10-9 per amino acid site per year was calculated for the central portion of the enzyme (residues 69-141), while N-terminal sequence (residues 1-68) and 142-210 fragment evolved with kaa of 1.03·10-9 and 0.81?·10-9, respectively.
Key words: thiamine triphosphatase, molecular evolution rate, mammals.
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