title: A plasmodial alpha-tubulin cDNA from Physarum polycephalum. Nucleotide sequence and comparative analysis.
abstract: As the first step towards correlating structure and function of tubulin in the slime mold Physarum polycephalum we have elucidated the nucleotide sequence of a cDNA that appears to code for all but the last 25 to 30 C-terminal amino acids of a plasmodial alpha-tubulin. Differences in amino acid sequence from those of other alpha-tubulins are distributed fairly evenly throughout the sequence, although a relatively extensive conserved region is found in position 396 to 426 near the C terminus. A small region in position 298 to 307 contains a cluster of amino acid residues unique to Physarum alpha-tubulin. The sequence is 70% homologous to two yeast alpha-tubulins and about 83% homologous to five animal alpha-tubulins. A comparison of the homologies of all the known alpha-tubulins indicates that a large decrease in the accepted point mutation rate has occurred during the evolution of the metazoa, suggesting a major functional specialization of microtubules.
mesh_terms: D001483:Base Sequence; D004270:DNA, Circular; D004271:DNA, Fungal; D010804:Physarum / Q000032:analysis*; D010961:Plasmodium; D014404:Tubulin / Q000032:analysis*
chemical_list: D004270:DNA, Circular; D004271:DNA, Fungal; D014404:Tubulin