Tsuru D, Imajo S, Morikawa S, Yoshimoto T, Ishiguro M
School of Pharmaceutical Sciences, Nagasaki University.
J Biochem. 1993 Jan;113(1):101-5. doi: 10.1093/oxfordjournals.jbchem.a123991.
The active site structure of the Zn-containing neutral protease from Bacillus subtilis var. amylosacchariticus (BANP) was predicted by computer-aided modeling on the basis of the three-dimensional structure of thermolysin (TLN). As expected from the high homology in amino acid sequence of the two enzymes, the overall folding of BANP was very similar to that of TLN. Glu144, Tyr158, and His228 of BANP were located near the active site Zn ion, to which three amino acid residues, His143, His147, and Glu167, were coordinated. This model is supported by the previous results that chemical modifications of Tyr158 and photooxidation of His228 of BANP markedly affect the proteolytic activity of the enzyme. Interestingly, BANP was found to be significantly less sensitive to metalloprotease inhibitors such as phosphoramidon and talopeptin. From a comparison of the enzyme-inhibitor complex models between BANP and thermolysin, it is suggested that replacement of Thr129 in TLN by Phe130 in BANP is related to difference in inhibitor sensitivity between BANP and TLN.
基于嗜热菌蛋白酶（TLN）的三维结构，通过计算机辅助建模预测了枯草芽孢杆菌淀粉酶变种（BANP）含锌中性蛋白酶的活性位点结构。正如从这两种酶的氨基酸序列高度同源所预期的那样，BANP的整体折叠与TLN非常相似。BANP的Glu144、Tyr158和His228位于活性位点锌离子附近，His143、His147和Glu167这三个氨基酸残基与该锌离子配位。该模型得到了先前结果的支持，即BANP的Tyr158化学修饰和His228光氧化显著影响该酶的蛋白水解活性。有趣的是，发现BANP对金属蛋白酶抑制剂如磷酰胺素和他洛肽ptin的敏感性明显较低。通过比较BANP和嗜热菌蛋白酶之间的酶 - 抑制剂复合物模型，表明BANP中Phe130取代TLN中的Thr129与BANP和TLN之间抑制剂敏感性的差异有关。
