Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Biochemistry. 2010 Sep 21;49(37):7975-7. doi: 10.1021/bi101177a.
The expression of the gene products in many methicillin-resistant Staphylococcus aureus (MRSA) strains is regulated by the gene repressor BlaI. Here we show that BlaI is a mixture of monomer and dimer at in vivo concentrations, binds to the operator regions preferentially as a monomeric protein, and the measured dissociation constants and in vivo concentrations account for the basal level transcription of the resistance genes. These observations for the first time provide a quantitative picture of the processes that take place in the cytoplasm that lead to the induction of antibiotic resistance factors to counter the challenge by β-lactams.
许多耐甲氧西林金黄色葡萄球菌 (MRSA) 菌株中的基因产物表达受基因抑制剂 BlaI 调控。本文作者表明，BlaI 在体内浓度下以单体和二聚体的形式存在，优先作为单体蛋白结合到操纵区，且测定的离解常数和体内浓度解释了耐药基因的基础转录水平。这些观察结果首次提供了一个定量的描述，阐释了在细胞质中发生的诱导抗生素耐药因子的过程，以应对β-内酰胺类药物的挑战。
