Frutiger S, Hughes G J, Paquet N, Lüthy R, Jaton J C
Department of Medical Biochemistry, University of Geneva Medical Center, Switzerland.
Biochemistry. 1992 Dec 22;31(50):12643-7. doi: 10.1021/bi00165a014.
The assignment of disulfide bonds in human J chain and its covalent pairing with immunoglobulin M was determined under conditions which minimize disulfide bond interchange. We show that in J chain the three intradisulfide bridges are formed between Cys 12 and 100, Cys 71 and 91, and Cys 108 and 133. Previous reports [reviewed by Koshland, M. E. (1985) Annu. Rev. Immunol. 3, 425-453] have proposed that cysteines 12, 14, or 68 were linked to the penultimate cysteine 575 of two mu chain tails. In this work, we demonstrate that cysteines 14 and 68 are disulfide-bridged to mu chains. A revised, albeit putative, model of J chain folding is presented which takes into account the correct disulfide pairing and the predictive secondary structure assignment.
在使二硫键交换最小化的条件下，确定了人J链中二硫键的分配及其与免疫球蛋白M的共价配对。我们发现，在J链中，三个链内二硫键分别形成于半胱氨酸12与100、半胱氨酸71与91以及半胱氨酸108与133之间。先前的报道[由Koshland, M. E.（1985年）综述，《免疫学年度评论》3, 425 - 453]提出，半胱氨酸12、14或68与两条μ链尾部的倒数第二个半胱氨酸575相连。在这项研究中，我们证明半胱氨酸14和68与μ链形成二硫键连接。本文提出了一个经过修订的（尽管是推测性的）J链折叠模型，该模型考虑了正确的二硫键配对以及预测的二级结构分配。
