STEREOCHEMICAL MODELING OF DISULFIDE BRIDGES - CRITERIA FOR INTRODUCTION INTO PROTEINS BY SITE-DIRECTED MUTAGENESIS
STEREOCHEMICAL MODELING OF DISULFIDE BRIDGES - CRITERIA FOR INTRODUCTION INTO PROTEINS BY SITE-DIRECTED MUTAGENESIS
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DOI：
10.1093/protein/3.2.95
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发表时间：
1989-11-01
期刊：
影响因子：
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通讯作者：
BALARAM, P
中科院分区：
文献类型：
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作者：
SOWDHAMINI, R;SRINIVASAN, N;BALARAM, P
已经开发出一种计算机建模程序，用于评估蛋白质中残基对作为引入胱氨酸二硫化物交联的潜在位点的立体化学适宜性。与C.alpha.-C.alpha的残基对。 ≤6.5 ANG 的距离和C.beta.-C.beta。 ≤4.5 ANG 的距离使用 MODIP 程序选择 S 原子的几何固定。使用二硫键中各种扭转角和 S-S 键长度的结构参数的限制来评估建模的二硫化物的立体化学。已使用已知晶体结构的胱氨酸肽和来自于≤2.ANG确定的25个可用蛋白质晶体结构的103个二硫桥的例子来检查该程序正确建模二硫键的能力。解决。本文对三种带有工程化二硫化物的蛋白质（T4 溶菌酶、二氢叶酸还原酶和枯草杆菌蛋白酶）的结果进行了分析。在枯草杆菌蛋白酶中鉴定出两个引入“立体化学最佳”二硫化物的位置。
A computer modeling procedure for assessing the stereochemical suitability of pairs of residues in proteins as potential sites for introduction of cystine disulfide crosslinks has been developed. Residue pairs with C.alpha.-C.alpha. distances of .ltoreq.6.5 .ANG. and C.beta.-C.beta. distances of .ltoreq.4.5 .ANG. are chosen for geometrical fixation of S atoms using the program MODIP. The stereochemistry of the modeled disulfides is evaluated using limits for the structural parameters of the various torsion angles and S-S bond length in the disulfide bridge. The ability of the procedure to correctly model disulfides has been checked with examples of cystine peptides of known crystal structures and 103 disulfide bridges from 25 available protein crystal structures determined at .ltoreq.2 .ANG. resolution. An analysis of results on three proteins with engineered disulfides, T4 lysozyme, dihydrofolate reductase and subtilisin, is presented. Two positions for the introduction of ''stereochemically optimal'' disulfides are identified in subtilisin.