Molecular characterization of the copper transport system in Staphylococcus aureus

• Published in: Microbiology (Society for General Microbiology) Vol. 153; no. 12; pp. 4274 - 4283
• Main Authors: Sitthisak, Sutthirat, Knutsson, Lawrence, Webb, James W, Jayaswal, Radheshyam K
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01-12-2007; Society for General Microbiology
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Biological Transport; Copper - metabolism; Copper - pharmacology; Culture Media - chemistry; Fundamental and applied biological sciences. Psychology; Gene Deletion; Gene Expression Regulation, Bacterial; Iron - metabolism; Iron - pharmacology; Lead - metabolism; Lead - pharmacology; Microbiology; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Mutagenesis, Site-Directed; Permeability, membrane transport, intracellular transport; Staphylococcus aureus; Staphylococcus aureus - drug effects; Staphylococcus aureus - genetics; Staphylococcus aureus - growth & development; Staphylococcus aureus - metabolism; Characterization; Cysteine; Transportation system; Membrane transport; Chaperone; Bacteria; Micrococcales; Micrococcaceae; Copper; Staphylococcus aureus
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2007/009860-0

1 Department of Biological Sciences, Illinois State University, Normal, IL 61790, USA
2 Department of Chemistry, Illinois State University, Normal, IL 61790, USA
Correspondence Radheshyam K. Jayaswal drjay{at}ilstu.edu
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 .
Abbreviations: BCA, bicinchoninic acid; IAA, iminodiacetic acid-agarose; MBD, metal-binding domain