[Comparative analysis of spatial organization of myoglobins. II. Secondary structure]

An analysis of probability of distribution curves of alpha-helical sites and bends of polypeptide chains of myoglobins in half-water mammals (beaver, nutria, muskrat, otter) carried out in comparison with those of myoglobins of the horse and Sperm whale (X-ray diffraction analysis has revealed their tertiary structure) has revealed a coincidence of the secondary structure sites end bends of the chain in the studied respiratory hemoproteins of muscles. Despite a considerable number of amino acid substitutions the profiles of alpha-helicity and B-bends of the compared proteins are practically identical. This indicates to the "resistance" of the probability curves to amino acid substitutions and to retention of the tertiary structure of myoglobins in evolutionary remote species of the animals.