3-methylaspartase从tetanomorphum梭状芽胞杆菌的结构功能通过常见的烯醇酶化学步骤。
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亚松森M, Blankenfeldt W,巴洛约,Gani D,奈史密斯JH
3-methylaspartase从tetanomorphum梭状芽胞杆菌的结构功能通过常见的烯醇酶化学步骤。
J生物化学杂志。2002年3月8日,277(10):8306 - 11所示。Epub 2001年12月17日。
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11748244 (在PubMed]
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Methylaspartate ammonia-lyase (3-methylaspartase发作;EC)催化氨的可逆反消除L-threo - (2 s, 3 s) 3-methylaspartic酸给mesaconic酸。这个反应对谷氨酸的主要分解代谢的途径在于tetanomorphum梭状芽胞杆菌。MAL需要单价和二价阳离子代数余子式的催化活性。酶引起了兴趣,因为它潜在的使用作为一种生物催化剂。c . tetanomorphum MAL的结构解决了单波长反常衍射1.9 a分辨率的方法。二价金属离子复杂的蛋白质也被确定。MAL是为每个单体组成的两个领域。1是一种α/ beta-barrel和其它较小的领域主要是beta-strands。较小的域部分阻塞的C末端桶,形成了一个大裂口。 The structure identifies MAL as belonging to the enolase superfamily of enzymes. The metal ion site is located in a large cleft between the domains. Potential active site residues have been identified based on a combination of their proximity to a metal ion site, molecular modeling, and sequence homology. In common with all members of the enolase superfamily, the carboxylic acid of the substrate is co-ordinated by the metal ions, and a proton adjacent to a carboxylic acid group of the substrate is abstracted by a base. In MAL, it appears that Lys(331) removes the alpha-proton of methylaspartic acid. This motif is the defining mechanistic characteristic of the enolase superfamily of which all have a common fold. The degree of structural conservation is remarkable given only four residues are absolutely conserved.