2zcm
From Proteopedia
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Crystal structure of IcaR, a repressor of the TetR family
Overview
Expression of the gene cluster icaADBC is necessary for biofilm production, in Staphylococcus epidermidis. The ica operon is negatively controlled by, the repressor IcaR. Here, the crystal structure of IcaR was determined and, the refined structure revealed a homodimer comprising entirely, alpha-helices, typical of the tetracycline repressor protein family for, gene regulations. The N-terminal domain contains a conserved, helix-turn-helix DNA-binding motif with some conformational variations, indicating flexibility in this region. The C-terminal domain shows a, complementary surface charge distribution about the dyad axis, ideal for, efficient and specific dimer formation. The results of the electrophoretic, mobility shift assay and isothermal titration calorimetry suggested that a, 28 bp core segment of the ica operator is implicated in the cooperative, binding of two IcaR dimers on opposite sides of the duplex DNA. Computer, modeling based on the known DNA-complex structure of QacR and, site-specific mutagenesis experiments showed that direct protein-DNA, interactions are mostly conserved, but with slight variations for, recognizing the different sequences. By interfering with the binding of, IcaR to DNA, aminoglycoside gentamicin and other antibiotics may activate, the icaADBC genes and elicit biofilm production in S. epidermidis, and, likely S. aureus, as a defense mechanism.
About this Structure
2ZCM is a Single protein structure of sequence from Staphylococcus epidermidis. Full crystallographic information is available from OCA.
Reference
Crystal structure of IcaR, a repressor of the TetR family implicated in biofilm formation in Staphylococcus epidermidis., Jeng WY, Ko TP, Liu CI, Guo RT, Liu CL, Shr HL, Wang AH, Nucleic Acids Res. 2008 Jan 21;. PMID:18208836
Page seeded by OCA on Wed Feb 13 08:15:04 2008
