Song Liya, Wang Mingzhu, Shi Jiaji, Xue Zhiquan, Wang Mei-Xiang, Qian Shijun
State Key Laboratories of Transducer Technology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
Biochem Biophys Res Commun. 2007 Oct 19;362(2):319-24. doi: 10.1016/j.bbrc.2007.07.184. Epub 2007 Aug 14.
The crystal structure of Fe-type nitrile hydratase from Rhodococcus erythropolis AJ270 was determined at 1.3A resolution. The two cysteine residues (alphaCys(112) and alphaCys(114)) equatorially coordinated to the ferric ion were post-translationally modified to cysteine sulfinic acids. A glutamine residue (alphaGln(90)) in the active center gave double conformations. Based on the interactions among the enzyme, substrate and water molecules, a new mechanism of biocatalysis of nitrile hydratase was proposed, in which the water molecule activated by the glutamine residue performed as the nucleophile to attack on the nitrile which was simultaneously interacted by another water molecule coordinated to the ferric ion.
在1.3埃分辨率下测定了来自红平红球菌AJ270的铁型腈水合酶的晶体结构。与铁离子赤道配位的两个半胱氨酸残基（αCys(112)和αCys(114)）经翻译后修饰为半胱氨酸亚磺酸。活性中心的一个谷氨酰胺残基（αGln(90)）呈现出两种构象。基于酶、底物和水分子之间的相互作用，提出了一种新的腈水合酶生物催化机制，其中由谷氨酰胺残基激活的水分子作为亲核试剂攻击腈，同时另一个与铁离子配位的水分子与腈相互作用。
