THE REFINED CRYSTAL-STRUCTURE OF SUBTILISIN CARLSBERG AT 2.5 A RESOLUTION
THE REFINED CRYSTAL-STRUCTURE OF SUBTILISIN CARLSBERG AT 2.5 A RESOLUTION
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DOI：
10.1093/protein/2.4.271
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发表时间：
1988-10-01
期刊：
影响因子：
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通讯作者：
PETSKO, GA
中科院分区：
文献类型：
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作者：
NEIDHART, DJ;PETSKO, GA
我们在这里报告了嘉士伯天然枯草杆菌蛋白酶的 X 射线晶体结构，在 2.5 ANG 处解析。通过分子置换和约束最小二乘法将分辨率精化为 0.206 的晶体残差 (.SIGMA..dblvert.Fo .sbd. Fc.dblvert./.SIGMA. Fo )。我们将该结构与枯草杆菌蛋白酶 BPN/ 的晶体结构进行比较。我们发现，尽管枯草杆菌嘉士伯相对于枯草杆菌蛋白酶 BPN'' 有 82 个氨基酸取代和 1 个缺失，但这些酶的结构非常相似。我们计算均方根值枯草杆菌蛋白酶Carlsberg和枯草杆菌蛋白酶BPN''中的等效α-碳位置之间的差异仅为0.55ANG。这证实了先前基于eglin-c与枯草杆菌蛋白酶Carlsberg复合物的X射线晶体结构的这两种枯草杆菌蛋白酶之间广泛结构同源性的报道[McPhalen，C.A.，Schnebli，H.P.和詹姆斯，M.N.G. (1985) FEBS 通讯，188, 55； Bode, W.、Papamokos, E. 和 Musil, D. (1987) Eur。生物化学杂志，166, 673-692]。此外，我们发现枯草杆菌蛋白酶 Carlsberg 和 BPN'' 的天然活性位点实际上是相同的。虽然残基 217 和 156 处的保守取代可能分别对底物结合位点 S1'' 和 S1 的环境产生微妙的影响，但我们发现枯草杆菌蛋白酶 Carlsberg 和 BPN'' 在识别模型底物方面存在差异的报道没有明显的结构相关性。特别是，我们没有发现任何证据表明枯草杆菌嘉士伯中的疏水结合口袋 S1 比枯草杆菌蛋白酶 BPN 中的相应结合位点“更深”、“更窄”或“极性较小”[Karasaki 和 Ohno (1978) J. Biochem., Tokyo, 84, 531-538]。
We report here the X-ray crystal structure of native subtilisin Carlsberg, solved at 2.5 .ANG. resolution by molecular replacement and refined by restrained least squares to a crystallographic residual (.SIGMA..dblvert.Fo .sbd. Fc.dblvert./.SIGMA. Fo ) of 0.206. we compare this structure to the crystal structure of subtilisin BPN/. We find that, despite 82 amino acid substitutions and one deletion in subtilism Carlsberg relative to subtilisin BPN'', the structures of these enzymes are remarkably similar. We calculate an r.m.s. difference between equivalent .alpha.-carbon poisitions in subtilisin Carlsberg and subtilisin BPN'' of only 0.55 .ANG.. This confirms previous reports of extensive structural homology between these two subtilisins based on X-ray crystal structures of the complex of eglin-c with subtilisin Carlsberg [McPhalen, C.A., Schnebli, H.P. and James, M.N.G. (1985) FEBS Lett., 188, 55; Bode, W., Papamokos, E. and Musil, D. (1987) Eur. J. Biochem., 166, 673-692]. In addition, we find that the native active sites of subtilisins Carlsberg and BPN'' are virtually identical. While conservative substitutions at residues 217 and 156 may have subtle effects on the environments of substrate-binding sites S1'' and S1 respectively, we find no obvious structural correlate for reports that subtilisins Carlsberg and BPN'' differ in their recognition of model substrates. In particular, we find no evidence that the hydrophobic binding pocket S1 in subtilisin Carlsberg is ''deeper'', ''narrower'' or ''less polar'' than the corresponding binding site in subtilisin BPN'' [Karasaki and Ohno (1978) J. Biochem., Tokyo, 84, 531-538].