Hemolymph Coagulation and Defence Systems in Invertebrate Animals

无脊椎动物的血淋巴凝固和防御系统

基本信息

批准号：
62480453
负责人：
IWANAGA Sadaaki
金额：
$ 4.35万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

The horseshoe crab clotting factor, factor C, present in the hemocytes is a serine-protease zymogen activated with lipopolysaccharide. It is a two-chain glycoprotein (M_r = 123,000) composed of a heavy chain (M_r = 80,000) and a light chain (M_r = 43,000) [T. Nakamura et al. (1986) Eur. J. Biochem. 154, 511-521]. In our continued study of this zymogen, we have now also found a single-chain form of factor C (M_r = 123,000) in the hemocyte lysate. the heavy chain had the NH_2-terminal sequence of Ser-Gly-Val-Asp-, consistent with that of the single- chain factor C, indicating that the heavy chain is derived from the NH_2-terminal part of the molecule. The light chain had an NH_2-terminal sequence of Ser-Ser-Gln-Pro-. Incubation of the two-chain zymogen with lipopolysaccharide resulted in the cleavage of a Phe-Ile bond between residues 72 and 73 of the light chain. Concomitant with this cleavage, the A (72 amino acid residues) and B chains derived from the light chain were formed. The complete amino acid sequence of the A chain was determined by automated edman degradation. The A chain contained a typical segment which is similar in sequence to a family of repeats in human _2-glycoprotein I, complement factors B, protein H, C4b-binding protein, and coagulation factor XIII b subunit. The NH_2-terminal sequence of the B chain was Ile-Trp-Asn-Gly-. This chain contained the serine-active site sequence-Asp-Ala-Cys-Ser-Gly-Asp-Ser-Gly-Gly-Pro-.These results indicate that horseshoe crab factor C exists in the hemocytes in a single-chain zymogen from and is converted to an acitve serine protease by hydrolysis of a specific Phe-Ile peptide bond.

血细胞中存在的马蹄蟹凝结因子C因子C C是用脂多糖激活的丝氨酸 - 蛋白酶Zymogen。这是由重链（M_R = 80,000）和轻链（M_R = 43,000）组成的两链糖蛋白（M_R = 123,000）[T。 Nakamura等。（1986）欧洲。 J. Biochem。 154，511-521]。在我们对这种酶原的持续研究中，我们现在还发现了血细胞裂解物中的一种单链形式的因子C（M_R = 123,000）。重链具有ser-gly-val-asp-的NH_2末端序列，与单链因子C相一致，表明重链来自分子的NH_2-末端部分。轻链具有Ser-Ser-Gln-Pro-的NH_2末端序列。将两链Zymogen与脂多糖一起孵育，导致轻链72和73之间的Phe-Eile键裂解。与这种裂解，A（72个氨基酸残基）和来自轻链的B链的伴随。 A链的完整氨基酸序列由自动Edman降解确定。 A链包含一个典型的段，其顺序与人_2-糖蛋白I，补体因子B，蛋白H，C4B结合蛋白和凝结因子XIII B亚基相似。 B链的NH_2末端序列是Ile-Trp-Asn-Gly-。该链中包含丝氨酸活性位点序列-ASP-ALA-CYS-SER-GLY-ASS-GLY-ASSER-GLY-GLY-PRO-。这些结果表明，在单链Zymogen中，在单链Zymogen中存在马蹄形C，并通过特定的phe-eile-eile-eile-ile-ece peptide peptide peptide peptide peptide peptide Craby zymogen中存在，并转化为Acitve seriitve erseace eresease蛋白酶。