文章基本信息

标题：Insights into the molecular mechanism of dehalogenation catalyzed by D-2-haloacid dehalogenase from crystal structures
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作者：Yayue Wang ; Yanbin Feng ; Xupeng Cao 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：1454
DOI：10.1038/s41598-017-19050-x
语种：English
出版社：Springer Nature
摘要：O incorporation experiment. HadD AJ1 is an α-helical hydrolase that forms a homotetramer with its monomer including two structurally axisymmetric repeats. The product-bound complex structure was trapped with L-lactic acid in the active site, which is framed by the structurally related helices between two repeats. Site-directed mutagenesis confirmed the importance of the residues lining the binding pocket in stabilizing the enzyme-substrate complex. Asp205 acts as a key catalytic residue and is responsible for activating a water molecule along with Asn131. Then, the hydroxyl group of the water molecule directly attacks the C2 atom of the substrate to release the halogen ion instead of forming an enzyme-substrate ester intermediate as observed in L-2-haloacid dehalogenases. The newly revealed structural and mechanistic information on D-DEX may inspire structure-based mutagenesis to engineer highly efficient haloacid dehalogenases.