Sitthisak Sutthirat, Knutsson Lawrence, Webb James W, Jayaswal Radheshyam K
Department of Biological Sciences, Illinois State University, Normal, IL 61790, USA.
Department of Chemistry, Illinois State University, Normal, IL 61790, USA.
Microbiology (Reading). 2007 Dec;153(Pt 12):4274-4283. doi: 10.1099/mic.0.2007/009860-0.
The Staphylococcus aureus copA gene codes for a putative copper-translocating P-type ATPase and the downstream copZ gene codes for a copper chaperone. Genome database analyses demonstrate that these copper transport genes are highly conserved in S. aureus. The expression of copA and copZ was inducible by copper and to some extent by ferric and lead ions. A mutant strain containing a partially deleted copA gene was more sensitive than the parent strain to copper, ferric and lead ions. The copper-sensitive phenotype was due to the accumulation of intracellular copper and thus the copA product is involved in the export of copper ions. The metal-sensitive phenotype of the mutant was complemented in trans by a 2.7 kbp DNA containing copA. We have cloned and overexpressed the metal-binding domains of CopA and CopZ and have shown by site-directed mutagenesis that the cysteine residues in the CXXC metal-binding motif in CopA are involved in copper binding and thus play an important role in copper transport in S. aureus.
金黄色葡萄球菌copA基因编码一种推定的铜转运P型ATP酶，其下游的copZ基因编码一种铜伴侣蛋白。基因组数据库分析表明，这些铜转运基因在金黄色葡萄球菌中高度保守。copA和copZ的表达可被铜诱导，在一定程度上也可被铁离子和铅离子诱导。含有部分缺失copA基因的突变菌株比亲本菌株对铜、铁离子和铅离子更敏感。铜敏感表型是由于细胞内铜的积累，因此copA产物参与铜离子的输出。突变体的金属敏感表型可被含有copA的2.7 kbp DNA反式互补。我们已经克隆并过表达了CopA和CopZ的金属结合结构域，并通过定点诱变表明，CopA中CXXC金属结合基序中的半胱氨酸残基参与铜结合，因此在金黄色葡萄球菌的铜转运中起重要作用。
