Structure of the O-acetylserine sulfhydrylase isoenzyme CysM from Escherichia coli
Structure of the O-acetylserine sulfhydrylase isoenzyme CysM from Escherichia coli
复制标题
DOI：
10.1021/bi050485
复制
发表时间：
2005-06-21
期刊：
影响因子：
2.9
通讯作者：
Schulz, GE
中科院分区：
文献类型：
--
作者：
Claus, MT;Zocher, GE;Schulz, GE
O-乙酰丝氨酸巯基酶参与细菌和植物体内L-半胱氨酸的生物合成。大肠杆菌同工酶B(CysM)在2.7埃分辨率下呈六方晶型(野生型)，在2.1埃分辨率下呈多面体孪生四方晶体(表面突变体)。结构叠加揭示了与同工酶A(CysK)相关的差异，并解释了不同底物的特异性。提出了CysM催化反应的几何模型。这两种同工酶都用于生产L氨基酸衍生物，作为合成肽和模拟肽药物的基石。由于CysM的结构揭示了活性中心主链的显著变化，它构成了具有新底物特异性的工程突变体的进一步起点。
The enzyme O-acetylserine sulfhydrylase participates in the biosynthesis Of L-Cysteine in bacteria and plants. The structure of isoenzyme B (CysM) from Escherichia coli was established in a hexagonal crystal form at 2.7 angstrom resolution (wild-type) and in a merohedrally twinned tetragonal crystal form at 2.1 angstrom resolution (surface mutant). Structural superpositions revealed the variations with respect to isoenzyme A (CysK) and explained the different substrate specificities. A geometric model of the reaction catalyzed by CysM is proposed. Both isoenzymes are used for the production Of L-amino acid derivatives as building blocks for the synthesis of peptides and peptidomimetic drugs. Since the structure of CysM revealed a remarkable main chain variation at the active center, it constitutes a further starting point for engineering mutants with novel substrate specificities.