1JT0

Crystal structure of a cooperative QacR-DNA complex

Summary for 1JT0

• Entry DOI: 10.2210/pdb1jt0/pdb
• Related: 1JT6 1JTY 1JUM 1JUP 1JUS
• Descriptor: QACA operator, HYPOTHETICAL TRANSCRIPTIONAL REGULATOR IN QACA 5'REGION, SULFATE ION, ... (4 entities in total)
• Functional Keywords: multidrug binding protein, cooperative dna binding, dimer of dimers, transcription-dna complex, transcription/dna
• Biological source: Staphylococcus aureus
• Total number of polymer chains: 6
• Total formula weight: 109621.54

Authors

Schumacher, M.A.,Miller, M.C.,Grkovic, S.,Brown, M.H.,Skurray, R.A.,Brennan, R.G. (deposition date: 2001-08-20, release date: 2002-03-08, Last modification date: 2024-02-07)

Primary citation

Schumacher, M.A.,Miller, M.C.,Grkovic, S.,Brown, M.H.,Skurray, R.A.,Brennan, R.G.
Structural basis for cooperative DNA binding by two dimers of the multidrug-binding protein QacR.
EMBO J., 21:1210-1218, 2002

PubMed Abstract: The Staphylococcus aureus multidrug-binding protein QacR represses transcription of the qacA multidrug transporter gene and is induced by multiple structurally dissimilar drugs. QacR is a member of the TetR/CamR family of transcriptional regulators, which share highly homologous N-terminal DNA-binding domains connected to seemingly non-homologous ligand-binding domains. Unlike other TetR members, which bind approximately 15 bp operators, QacR recognizes an unusually long 28 bp operator, IR1, which it appears to bind cooperatively. To elucidate the DNA-binding mechanism of QacR, we determined the 2.90 A resolution crystal structure of a QacR-IR1 complex. Strikingly, our data reveal that the DNA recognition mode of QacR is distinct from TetR and involves the binding of a pair of QacR dimers. In this unique binding mode, recognition at each IR1 half-site is mediated by a complement of DNA contacts made by two helix-turn-helix motifs. The inferred cooperativity does not arise from cross-dimer protein-protein contacts, but from the global undertwisting and major groove widening elicited by the binding of two QacR dimers.

PubMed: 11867549
DOI: 10.1093/emboj/21.5.1210

Experimental method

X-RAY DIFFRACTION (2.9 Å)