Expression of Four Methionine Sulfoxide Reductases inStaphylococcus aureus

[摘要] Staphylococcus aureuspossesses three MsrA enzymes (MsrA1, MsrA2, MsrA3) that reduce the S-epimer of methionine sulfoxide (MetO) and an MsrB enzyme that reduces R-MetO.The fourmsrgenes are expressed from three different promoters. ThemsrA1/msrBgenes are coexpressed.To determine the expression pattern ofmsrgenes, three independent reporter strains were constructed wheremsrpromoter was cloned in front of a promoterlesslacZand the resulting construct was integrated in the chromosome.Using these strains, it was determined that themsrA1/Bexpression is significantly higher inS. aureuscompared tomsrA2ormsrA3.Expression ofmsrA1/Bwas highest during stationary phase growth, but the expression ofmsrA2andmsrA3was highest during the early to midexponential growth phase.Expression ofmsrA1/Bwas induced by oxacillin and the expression ofmsrA3was upregulated by salt.Expression ofmsrA2remained unchanged under all tested conditions.

[学科分类] 微生物学和免疫学