High-resolution structures of RmIC from Streptococcus suis in complex with substrate analogs locate the active site of this class of enzyme
High-resolution structures of RmIC from Streptococcus suis in complex with substrate analogs locate the active site of this class of enzyme
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DOI：
10.1016/s0969-2126(03)00098-4
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发表时间：
2003-06-01
期刊：
影响因子：
5.7
通讯作者：
Naismith, JH
中科院分区：
文献类型：
--
作者：
Dong, CJ;Major, LL;Naismith, JH
自然界通过各种化学途径实现碳水化合物的差向异构化。一种常见的途径是通过由来自鼠李糖途径的dTDP-6-脱氧-D-木-4-己酮糖3，5-差向异构酶（RmlC）定义的酶类别进行的途径。早期的研究未能确定催化作用中的关键残留物。我们报道了来自猪链球菌2型的RmlC及其与dTDP-D-葡萄糖和dTDP-D-木糖的复合物的1.3埃结构。链球菌RmlC酶属于一个单独的亚组，与其他细菌的RmlC仅具有25%的同一性，但链球菌RmlC酶属于一个单独的亚组。suis酶具有与其它RmlC酶相似的动力学性质和结构。结构，序列比对和突变分析，现在允许可靠的鉴定催化残基和它们的作用。
Nature achieves the epimerization of carbohydrates by a variety of chemical routes. One common route is that performed by the class of enzyme defined by dTDP-6-deoxy-D-xylo-4-hexulose 3,5-epimerase (RmlC) from the rhamnose pathway. Earlier studies failed to identify the key residues in catalysis. We report the 1.3 Angstrom structure of RmlC from Streptococcus suis type 2 and its complexes with dTDP-D-glucose and dTDP-D-xylose. The streptococcal RmlC enzymes belong to a separate subgroup, sharing only 25% identity with RmlC from other bacteria, yet the S. suis enzyme has similar kinetic properties and structure to other RmlC enzymes. Structure, sequence alignment, and mutational analysis have now allowed reliable identification of the catalytic residues and their roles.