3psz

Crystal Structure of AhQnr, the Qnr protein from Aeromonas hydrophila (P21212 crystal form)

spinqualitylabelsall models 3psz, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3psz is a 2 chain structure with sequence from Aeromonas hydrophila subsp. hydrophila ATCC 7966. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: ACT, CAS, CSD, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0KF03_AERHH Publication Abstract from PubMed Quinolones inhibit bacterial type II DNA topoisomerases (e.g. DNA gyrase) and are among the most important antibiotics in current use. However, their efficacy is now being threatened by various plasmid-mediated resistance determinants. Of these, the pentapeptide repeat-containing (PRP) Qnr proteins are believed to act as DNA mimics and are particularly prevalent in Gram-negative bacteria. Predicted Qnr-like proteins are also present in numerous environmental bacteria. Here, we demonstrate that one such, Aeromonas hydrophila AhQnr, is soluble, stable, and relieves quinolone inhibition of Escherichia coli DNA gyrase, thus providing an appropriate model system for Gram-negative Qnr proteins. The AhQnr crystal structure, the first for any Gram-negative Qnr, reveals two prominent loops (1 and 2) that project from the PRP structure. Deletion mutagenesis demonstrates that both contribute to protection of E. coli DNA gyrase from quinolones. Sequence comparisons indicate that these are likely to be present across the full range of Gram-negative Qnr proteins. On this basis we present a model for the AhQnr:DNA gyrase interaction where loop1 interacts with the gyrase A 'tower' and loop2 with the gyrase B TOPRIM domains. We propose this to be a general mechanism directing the interactions of Qnr proteins with DNA gyrase in Gram-negative bacteria. Structural insights into quinolone antibiotic resistance mediated by pentapeptide repeat proteins: conserved surface loops direct the activity of a Qnr protein from a Gram-negative bacterium.,Xiong X, Bromley EH, Oelschlaeger P, Woolfson DN, Spencer J Nucleic Acids Res. 2011 Jan 11. PMID:21227918 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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