THE MUTANT ESCHERICHIA-COLI F112W CYCLOPHILIN BINDS CYCLOSPORINE-A IN NEARLY IDENTICAL CONFORMATION AS HUMAN CYCLOPHILIN
THE MUTANT ESCHERICHIA-COLI F112W CYCLOPHILIN BINDS CYCLOSPORINE-A IN NEARLY IDENTICAL CONFORMATION AS HUMAN CYCLOPHILIN
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DOI：
10.1021/bi00185a007
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发表时间：
1994-05-17
期刊：
影响因子：
2.9
通讯作者：
WAGNER, G
中科院分区：
文献类型：
--
作者：
FEJZO, J;ETZKORN, FA;WAGNER, G
周质大肠杆菌亲环素与人亲环素有较远的亲缘关系（34%的序列同一性）。比较了人和大肠杆菌的肽基脯氨酰异构酶活性、环孢菌素A结合和钙依赖性磷酸酶钙调神经磷酸酶的抑制。coli野生型和突变体蛋白。与人类亲环素一样，E. coli蛋白是顺-反肽基脯氨酰异构酶。然而，尽管人蛋白质与环孢菌素A紧密结合（K-d 17 nM），但E. coli蛋白则不具有此活性（K-d为3.4 μ M）。突变体F112 W E.大肠杆菌亲环蛋白具有增强的环孢菌素结合（K-d 170 nM）。至于人类蛋白质，E.大肠杆菌突变体与环孢菌素A抑制钙调磷酸酶。本文描述了在pH6.2时与突变体E结合的环孢菌素A的结构。大肠杆菌亲环蛋白的溶液NMR方法解决。尽管整体序列同一性较低，但结合的环孢菌素A的结构在两种蛋白质中几乎相同。为了评估环孢菌素结合位点的差异，野生型E.将大肠杆菌亲环素与未复合的人亲环素A的结构以及与环孢菌素结合的结构进行了比较。尽管结合的环孢菌素A的结构相似，但E.大肠杆菌蛋白质在距离色氨酸121（人序列）最远的位点上是实质上不同的。该位点通过在E.大肠杆菌蛋白质，取代人类蛋白质中的另一个环。
The periplasmic Escherichia coli cyclophilin is distantly related to human cyclophilin (34% sequence identity). Peptidyl-prolyl isomerase activity, cyclosporin A binding, and inhibition of the calcium-dependent phosphatase calcineurin are compared for human and E. coli wild-type and mutant proteins. Like human cyclophilin, the E. coli protein is a cis-trans peptidyl-prolyl isomerase. However, while the human protein binds cyclosporin A tightly (K-d 17 nM), the E. coli protein does not (K-d 3.4 mu M). The mutant F112W E. coli cyclophilin has enhanced cyclosporin binding (K-d 170 nM). As for the human protein, the complex of the E. coli mutant with cyclosporin A inhibits calcineurin. Here we describe the structure at pH 6.2 of cyclosporin A bound to the mutant E. coli cyclophilin as solved with solution NMR methods. Despite the low overall sequence identity, the structure of the bound cyclosporin A is virtually identical in both proteins. To assess differences of the cyclosporin binding site, the solution structure of wild-type E. coli cyclophilin was compared with structures of uncomplexed human cyclophilin A and with cyclosporin bound. Despite the structural similarity of bound cyclosporin A, the architecture of the binding site in the E. coli protein is substantially different at the site most distant to tryptophan 121 (human sequence). This site is constructed by a five-residue insertion in a loop of the E. coli protein, replacing another loop in the human protein.