| Budget Amount *help |
¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1992: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Acrosomal proteins from Mytilus edulis sperm were separated into 11 fractions by a reverse phase HPLC. Among them, three major proteins, named M3, M6 and M7, had strong egg vitelline coat lysin and the first polar body releasing activities. They were present as a monomer and the molecular mass was estimated to be 19 kDa(M3), and 22 kDa(M6 and M7) by SDS-PAGE. The amino acid sequences of these proteins were determined by peptide sequence analysis. The sequence of M7 was confirmed by cDNA sequence analysis and revealed to be synthesized prepro-protein. The mature M6 and M7 proteins were composed of 180 amino acid residues and 76% identical sequence. On the other hand, M3 was composed of 149 amino acid residues and the sequence was different from M6 or M7 (26 % identical), however, positions of six cysteine residues involved in these three proteins were conserved. From the sequence similarity, they seemed to have carbohydrate recognition domain structure of C-type lectin and they really bound to vitelline coats. Thus the mechanism that lysin lyzes vitelline coats by non-enzymatic fashion is that these proteins bind to carbohydrate or carbohydrate-moiety of sugar proteins which consist of membrane and decompose the structure membrane. Decomposition of the membrane or lectin-like activity of M3,M6 and M7 seems to induce the release of the first polar body.
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