The nature of Staphylococcus aureus MurA and MurZ and approaches for detection of peptidoglycan biosynthesis inhibitors
The nature of Staphylococcus aureus MurA and MurZ and approaches for detection of peptidoglycan biosynthesis inhibitors
复制标题
DOI：
10.1111/j.1365-2958.2009.06648.x
复制
发表时间：
2009-04-01
影响因子：
3.6
通讯作者：
Chopra, Ian
中科院分区：
文献类型：
--
作者：
Blake, Katy L.;O'Neill, Alex J.;Chopra, Ian
金黄色葡萄球菌和许多其他革兰氏阳性生物体含有两个编码 UDP-N-乙酰氨基葡萄糖烯醇丙酮基转移酶活性的基因（murA 和 murZ），用于催化肽聚糖生物合成的第一个关键步骤。我们独立灭活了金黄色葡萄球菌中的 murA 和 murZ，并确定它们都可以维持活力。 MurA 和 MurZ 酶的纯化和表征表明它们在体外生化上相似，与通过分子建模预测的同工酶的相似整体结构一致。然而，MurA 似乎是葡萄球菌细胞中使用的主要酶。因此，在指数生长期间，murA表达比murZ表达高约五倍，并且在murA失活后金黄色葡萄球菌的肽聚糖含量减少约25%，但在murZ失活后几乎保持不变。尽管在正常生长期间表达水平较低，但在暴露于肽聚糖生物合成抑制剂后，murZ 表达被强烈诱导（高达六倍），而 murA 则未观察到这种情况。本研究中产生的菌株被验证为潜在工具，可使用已知的途径抑制剂来识别针对肽聚糖生物合成的新型抗葡萄球菌药物。
Staphylococcus aureus and a number of other Gram-positive organisms harbour two genes (murA and murZ) encoding UDP-N-acetylglucosamine enolpyruvyl transferase activity for catalysing the first committed step of peptidoglycan biosynthesis. We independently inactivated murA and murZ in S. aureus and established that either can sustain viability. Purification and characterization of the MurA and MurZ enzymes indicated that they are biochemically similar in vitro, consistent with similar overall structures predicted for the isozymes by molecular modelling. Nevertheless, MurA appears to be the primary enzyme utilized in the staphylococcal cell. Accordingly, murA expression was approximately five times greater than murZ expression during exponential growth, and the peptidoglycan content of S. aureus was reduced by approximately 25% following inactivation of murA, but remained almost unchanged following inactivation of murZ. Despite low level expression during normal growth, murZ expression was strongly induced (up to sixfold) following exposure to inhibitors of peptidoglycan biosynthesis, which was not observed for murA. Strains generated in this study were validated as potential tools for identifying novel anti-staphylococcal agents targeting peptidoglycan biosynthesis using known inhibitors of the pathway.