二硫循环的安排在人类α2-HS糖蛋白。相似的半胱氨酸蛋白酶抑制物和激肽原二硫桥结构。
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凯勒曼J, Haupt H, Auerswald EA, Muller-Ester W
二硫循环的安排在人类α2-HS糖蛋白。相似的半胱氨酸蛋白酶抑制物和激肽原二硫桥结构。
生物化学杂志。1989年8月25;264 (24):14121 - 8。
- PubMed ID
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2760061 (在PubMed]
- 文摘
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人类α2-HS糖蛋白的完整的二硫循环结构已被阐明。α2-HS糖蛋白从人血浆分离被发现是一个two-chain重和轻链组成的蛋白质。链的重链由α2-HS糖蛋白(吉冈,Y。Gejyo F。马蒂,T。Rickli, E·E。Burgi, W。、Offner g D。特,r F。施密德,k(1986)生物。261年化学,1665 - 1676)和连接肽的一部分已预测从相应的cDNA序列(李,C . C。鲍曼,b . H。杨,f (1987) Proc。国家的。学会科学。 U.S.A. 84, 4403-4407), whereas the light chain corresponds to the beta-chain of alpha 2-HS glycoprotein (Gejyo, F., Chang, J. L., Burgi, W., Schmid, K., Offner, G. D., Troxler, R. F., Van Halbeek, H., Dorland, L., Gerwig, G. J., Vliegenthart, J. F. G. (1983) J. Biol. Chem. 258, 4966-4971). Twelve half-cystine residues are present in the alpha 2-HS glycoprotein molecule, and 11 of them are positioned in the heavy chain and a single one in the light chain of the molecule; they form six disulfide bridges. The first and the last half-cystine residues of the amino acid sequence of alpha 2-HS glycoprotein are engaged in the formation of a loop spanning the extreme NH2- and COOH-terminal portions of the molecule, thereby connecting the heavy and light chains. The other 10 half-cystines residues are linked consecutively in the heavy chain and form five loops which span 4-19 amino acid residues. Among them are two pairs of loops which are characterized by mutual sequence homology. The particular arrangement of disulfide loops in alpha 2-HS glycoprotein is similar to the patterns of linearly arranged and tandemly repeated disulfide loops of cysteine proteinase inhibitors, i.e. the cystatins and the kininogens. It is concluded that alpha 2-HS glycoprotein represents a structural prototype of a novel family among the cystatin superfamily, characterized by the presence of two cystatin-like building blocks. Extensive similarity among the NH2-terminal sequences of alpha 2-HS glycoprotein and human histidine-rich glycoprotein suggest that the latter protein is another candidate protein of this new family.