1xat

STRUCTURE OF THE HEXAPEPTIDE XENOBIOTIC ACETYLTRANSFERASE FROM PSEUDOMONAS AERUGINOSA

spinqualitylabelsall models 1xat, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1xat is a 1 chain structure with sequence from Pseudomonas aeruginosa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, RCSB, PDBsum Function [CAT4_PSEAE] This enzyme is an effector of chloramphenicol (Cm) resistance in bacteria. Acetylates Cm but not 1-acetoxy-Cm. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The crystal structure of the xenobiotic acetyltransferase from Pseudomonas aeruginosa PA103 (PaXAT) has been determined, as well as that of its complex with the substrate chloramphenicol and the cofactor analogue desulfo-coenzyme A. PaXAT is a member of the large hexapeptide acyltransferase family of enzymes that display tandem repeated copies of a six-residue hexapeptide repeat sequence motif encoding a left-handed parallel beta helix (L betaH) structural domain. The xenobiotic acetyltransferase class of hexapeptide acyltransferases is composed of microbial enzymes that utilize acetyl-CoA to acylate a variety of hydroxyl-bearing acceptors. The active site of trimeric PaXAT is a short tunnel into which chloramphenicol and the cofactor analogue desulfo-CoA project from opposite ends. This tunnel is formed by the flat parallel beta sheets of two separate L betaH domains and an extended 39-residue loop. His 79 of the extended loop forms hydrogen bonds from its imidazole NE2 atom to the 3-hydroxyl group of chloramphenicol and from its ND1 group to the peptide oxygen of Thr 86. The interactions of this histidine residue are similar to those found in the structurally unrelated type III chloramphenicol acetyltransferase and suggest that His 79 of PaXAT may be similarly positioned and tautomerically stabilized to serve as a general base catalyst. Structure of the hexapeptide xenobiotic acetyltransferase from Pseudomonas aeruginosa.,Beaman TW, Sugantino M, Roderick SL Biochemistry. 1998 May 12;37(19):6689-96. PMID:9578552 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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