Singh Vineet K
Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, 800 West Jefferson Street, Kirksville, MO 63501, USA.
Can J Microbiol. 2014 Sep;60(9):625-8. doi: 10.1139/cjm-2014-0360. Epub 2014 Aug 18.
Staphylococcus aureus produces 3 MsrA enzymes (MsrA1, MsrA2, and MsrA3) and 1 MsrB enzyme. The genes encoding MsrA1 and MsrB are the first and second genes of a 4-gene operon in S. aureus. In a previous study, MsrA1-deficient S. aureus cells showed increased sensitivity to oxidative stress conditions in spite of a higher production of MsrB. In this study, an msrB mutant of S. aureus was created by site-directed mutagenesis that left the first gene of this locus, msrA1, intact. Studies with this mutant suggest that a deletion of MsrB increases resistance of S. aureus to H2O2 and oxacillin and that the mutant cells produce a higher level of carotenoids relative to wild-type S. aureus cells.
金黄色葡萄球菌产生3种甲硫氨酸亚砜还原酶A（MsrA）（MsrA1、MsrA2和MsrA3）和1种甲硫氨酸亚砜还原酶B（MsrB）。编码MsrA1和MsrB的基因是金黄色葡萄球菌中一个4基因操纵子的第一个和第二个基因。在先前的一项研究中，MsrA1缺陷型金黄色葡萄球菌细胞尽管MsrB产量较高，但对氧化应激条件的敏感性增加。在本研究中，通过定点诱变创建了金黄色葡萄球菌的msrB突变体，该位点的第一个基因msrA1保持完整。对该突变体的研究表明，MsrB的缺失增加了金黄色葡萄球菌对过氧化氢和苯唑西林的抗性，并且与野生型金黄色葡萄球菌细胞相比，突变体细胞产生更高水平的类胡萝卜素。
