嗜麦芽寡养单胞菌L1基因克隆及其结构功能关系

Gene cloning,structure and function analysis of L1 metallo-β-lactamase from Stenotrophomonas maltophilia

目的:建立临床分离嗜麦芽寡养单胞菌L1酶的三维空间结构,并预测其活性基团。方法:PCR法扩增L1基因,通过克隆、测序、序列比对获得其基因序列和氨基酸残基;应用InsightⅡ软件构建L1酶的三维结构。结果:野生型L1酶的分子整体形状为αβ/βα"丝带状",活性中心由15个残基组成。结论:Asp74在酶活性中心外,但与酶活性中心的残基His105及His110之间存在相互作用,可能对酶活性产生影响。

Objective：To establish a three-dimensional structure and predict the active group of L1 metallo-β-lactamase from Stenotrophomoncts maltophilia. Methods：L1 gene was amplified by PCR. The nucleotide sequences and amino-acid residues were obtained by gene cloning, sequencing and contrasting of sequences. The three-dimensional structure of L1 enzyme was determined using Insight Ⅱ software. Results：The molecular shape of wild-type L1 enzyme was αⅡ/Ⅱα fold, similar to ribbon. There were 15 residues in the active center. Conclusion ：Interaction exists between aspartic acid at position 74 and histidine at position 105 and 110 in L1 enzyme, although the residue at position 74 is not located in the active center. The residue at position 74 probably affects the activity of L1 enzyme.