4zdx

Structure of OXA-51 beta-lactamase

spinqualitylabelsall models 4zdx, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4zdx is a 1 chain structure with sequence from Acinetobacter baumannii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, KCX, TOE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q5QT35_ACIBA Publication Abstract from PubMed Class D beta-lactamases of Acinetobacter baumannii are enzymes of the utmost clinical importance, producing resistance to last resort carbapenem antibiotics. Although the OXA-51-like enzymes constitute the largest family of class D beta-lactamases, they are poorly studied and their importance in conferring carbapenem resistance is controversial. We present the detailed microbiological, kinetic, and structural characterization of the eponymous OXA-51 beta-lactamase. Kinetic studies show that OXA-51 has low catalytic efficiency for carbapenems, primarily due to the low affinity of the enzyme for these substrates. Structural studies demonstrate that this low affinity results from the obstruction of the enzyme active site by the side chain of Trp222, which presents a transient steric barrier to an incoming carbapenem substrate. The Trp222Met substitution relieves this steric hindrance and elevates the affinity of the mutant enzyme for carbapenems by 10-fold, significantly increasing the levels of resistance to these antibiotics. The ability of OXA-51 to evolve into a robust carbapenemase as the result of a single amino acid substitution may, in the near future, elevate the ubiquitous enzymes of the OXA-51 family to the status of the most deleterious A. baumannii carbapenemases, with dire clinical consequences. Structural Basis for Enhancement of Carbapenemase Activity in the OXA-51 Family of Class D beta-Lactamases.,Smith CA, Antunes NT, Stewart NK, Frase H, Toth M, Kantardjieff KA, Vakulenko S ACS Chem Biol. 2015 Jun 12. PMID:26042471 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Beta-lactamase 3D structures

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