Structure of the MecI repressor from Staphylococcus aureus in complex with the cognate DNA operator of mec
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529,Taiwan (China)
- Department of Medicinal Chemistry, School of Pharmacy and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)
- Department of Medicine and Department of Microbiology/Immunology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)
The up-and-down binding of dimeric MecI to mecA dyad DNA may account for the cooperative effect of the repressor. The dimeric repressor MecI regulates the mecA gene that encodes the penicillin-binding protein PBP-2a in methicillin-resistant Staphylococcus aureus (MRSA). MecI is similar to BlaI, the repressor for the blaZ gene of β-lactamase. MecI and BlaI can bind to both operator DNA sequences. The crystal structure of MecI in complex with the 32 base-pair cognate DNA of mec was determined to 3.8 Å resolution. MecI is a homodimer and each monomer consists of a compact N-terminal winged-helix domain, which binds to DNA, and a loosely packed C-terminal helical domain, which intertwines with its counter-monomer. The crystal contains horizontal layers of virtual DNA double helices extending in three directions, which are separated by perpendicular DNA segments. Each DNA segment is bound to two MecI dimers. Similar to the BlaI–mec complex, but unlike the MecI–bla complex, the MecI repressors bind to both sides of the mec DNA dyad that contains four conserved sequences of TACA/TGTA. The results confirm the up-and-down binding to the mec operator, which may account for cooperative effect of the repressor.
- OSTI ID:
- 22356338
- Journal Information:
- Acta Crystallographica. Section F, Vol. 62, Issue Pt 4; Other Information: PMCID: PMC2222568; PMID: 16582476; PUBLISHER-ID: en5164; OAI: oai:pubmedcentral.nih.gov:2222568; Copyright (c) International Union of Crystallography 2006; Country of input: International Atomic Energy Agency (IAEA); ISSN 1744-3091
- Country of Publication:
- United Kingdom
- Language:
- English
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