3PSZ

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

3PSZ の概要

• エントリーDOI: 10.2210/pdb3psz/pdb
• 関連するPDBエントリー: 3PSS
• 分子名称: Qnr, ACETATE ION, PHOSPHATE ION, ... (4 entities in total)
• 機能のキーワード: pentapeptide repeat, antibiotic resistance, type ii dna topoisomerase, cell cycle
• 由来する生物種: Aeromonas hydrophila
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 50562.23

構造登録者

Xiong, X.,Spencer, J. (登録日: 2010-12-02, 公開日: 2011-01-26, 最終更新日: 2024-11-13)

主引用文献

Xiong, X.,Bromley, E.H.C.,Oelschlaeger, P.,Woolfson, D.N.,Spencer, J.
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
Nucleic Acids Res., 2011

PubMed Abstract: 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.

PubMed: 21227918
DOI: 10.1093/nar/gkq1296

実験手法

X-RAY DIFFRACTION (2.2 Å)