Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia.
Protein Sci. 2014 May;23(5):594-602. doi: 10.1002/pro.2438. Epub 2014 Mar 11.
The MepRAB operon in Staphylococcus aureus has been identified to play a role in drug resistance. Although the functions of MepA and MepR are known, little information is available on the function of MepB. Here we report the X-ray structure of MepB to 2.1 Å revealing its structural similarity to the PD-(D/E)XK family of endonucleases. We further show that MepB binds DNA and RNA, with a higher affinity towards RNA and single stranded DNA than towards double stranded DNA. Notably, the PD-(D/E)XK catalytic active site residues are not conserved in MepB. MepB's association with a drug resistance operon suggests that it plays a role in responding to antimicrobials. This role is likely carried out through MepB's interactions with nucleic acids.
金黄色葡萄球菌中的 MepRAB 操纵子已被确定在耐药性中发挥作用。尽管已知 MepA 和 MepR 的功能，但关于 MepB 的功能知之甚少。在这里，我们报道了 MepB 的 X 射线结构，分辨率为 2.1Å，揭示了其与 PD-(D/E)XK 家族内切酶的结构相似性。我们进一步表明，MepB 结合 DNA 和 RNA，与 RNA 和单链 DNA 的亲和力高于双链 DNA。值得注意的是，MepB 中没有保守的 PD-(D/E)XK 催化活性位点残基。MepB 与耐药性操纵子的关联表明它在对抗微生物药物的反应中发挥作用。这种作用可能是通过 MepB 与核酸的相互作用来实现的。
