An Active Site Water Network in the Plasminogen Activator Pla from Yersinia pestis
An Active Site Water Network in the Plasminogen Activator Pla from Yersinia pestis
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DOI：
10.1016/j.str.2010.03.013
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发表时间：
2010-07-14
期刊：
影响因子：
5.7
通讯作者：
van den Berg, Bert
中科院分区：
文献类型：
--
作者：
Eren, Elif;Murphy, Megan;van den Berg, Bert
鼠疫菌纤溶酶原激活物Pla是一种外膜蛋白酶（omptin），对鼠疫的毒力有重要作用。在这里，我们提出了高分辨率的晶体结构的野生型，酶活性的PLA在1.9埃。该结构显示了位于活性位点残基D84和H2O8之间的水分子，其可能对应于亲核水。许多其他水分子存在于活性位点，连接对酶活性重要的残基。环L4中的R211侧链靠近亲核水，并且可能参与含氧阴离子中间体的稳定。H208的细微构象变化是由于脂多糖结合到桶的外部，这解释了omptins对脂多糖活性的不寻常依赖性。Pla结构表明了与纤溶酶原底物相互作用的模型，并提供了对omptin蛋白酶催化机制的更详细的理解。
The plasminogen activator Pla from Yersinia pestis is an outer membrane protease (omptin) that is important for the virulence of plague. Here, we present the high-resolution crystal structure of wild-type, enzymatically active Pla at 1.9 angstrom. The structure shows a water molecule located between active site residues D84 and H208, which likely corresponds to the nucleophilic water. A number of other water molecules are present in the active site, linking residues important for enzymatic activity. The R211 side-chain in loop L4 is close to the nucleophilic water and possibly involved in the stabilization of the oxyanion intermediate. Subtle conformational changes of H208 result from the binding of lipopolysaccharide to the outside of the barrel, explaining the unusual dependence of omptins on lipopolysaccharide for activity. The Pla structure suggests a model for the interaction with plasminogen substrate and provides a more detailed understanding of the catalytic mechanism of omptin proteases.