三酰甘油的晶体结构从假单胞菌脂肪酶不过揭示了一个高度开放构型在缺乏抑制剂。
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黄金KK,歌曲港元,胫骨DH,肯塔基州,Suh西南
三酰甘油的晶体结构从假单胞菌脂肪酶不过揭示了一个高度开放构型在缺乏抑制剂。
结构。1997年2月15日,5 (2):173 - 85。
- PubMed ID
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9032073 (在PubMed]
- 文摘
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背景:。脂酶家族的酶,催化甘油三酯的水解,广泛分布在许多生物体。真正的脂酶是有别于酯酶的特征界面激活他们在一个油水界面展示。脂酶是最常用的生物催化剂之一为有机反应在温和的条件下进行。他们的生物技术应用包括粮食和石油加工和制备光学纯手性中间体的合成药物。最近的几个脂酶结构研究提供一些线索理解水解活性的机制,界面激活和立体选择性。这项研究是为了提供细菌脂肪酶的结构信息,这是相对有限,相比于其他来源的酶。结果:。我们已经确定的晶体结构三酰甘油从假单胞菌脂肪酶不过(PcL)在缺乏约束抑制剂使用x射线晶体学。显示了脂肪酶的结构包含一个α/ beta-hydrolase褶皱和残留Ser87催化三分子组成,His286 Asp264。 The enzyme shares several structural features with homologous lipases from Pseudomonas glumae (PgL) and Chromobacterium viscosum (CvL), including a calcium-binding site. The present structure of PcL reveals a highly open conformation with a solvent-accessible active site. This is in contrast to the structures of PgL and PcL in which the active site is buried under a closed or partially opened 'lid', respectively. CONCLUSIONS: . PcL exhibits some structural features found in other lipases. The presence of the Ser-His-Asp catalytic triad, an oxyanion hole, and the opening of a helical lid suggest that this enzyme shares the same mechanisms of catalysis and interfacial activation as other lipases. The highly open conformation observed in this study is likely to reflect the activated form of the lipase at an oil-water interface. The structure suggests that the interfacial activation of bacterial lipases involves the reorganization of secondary structures and a large movement of the lid to expose the active site. This is similar to the mechanism described for other well characterized fungal and mammalian lipases.