2x3j

CO-COMPLEX STRUCTURE OF ACHROMOBACTIN SYNTHETASE PROTEIN D (ACSD) WITH ATP AND N-CITRYL-ETHYLENEDIAMINE FROM PECTOBACTERIUM CHRYSANTHEMI

spinqualitylabelsall models 2x3j, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2x3j is a 2 chain structure with sequence from Dickeya chrysanthemi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: ATP, GOL, MG, X3J Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q93AT8_DICCH Publication Abstract from PubMed Siderophores are known virulence factors, and their biosynthesis is a target for new antibacterial agents. A non-ribosomal peptide synthetase-independent siderophore biosynthetic pathway in Dickeya dadantii is responsible for production of the siderophore achromobactin. The D. dadantii achromobactin biosynthesis protein D (AcsD) enzyme has been shown to enantioselectively esterify citric acid with l-serine in the first committed step of achromobactin biosynthesis. The reaction occurs in two steps: stereospecific activation of citric acid by adenylation, followed by attack of the enzyme-bound citryl adenylate by l-serine to produce the homochiral ester. We now report a detailed characterization of the substrate profile and mechanism of the second (acyl transfer) step of AcsD enzyme. We demonstrate that the enzyme catalyzes formation of not only esters but also amides from the citryl-adenylate intermediate. We have rationalized the substrate utilization profile for the acylation reaction by determining the first X-ray crystal structure of a product complex for this enzyme class. We have identified the residues that are important for both recognition of l-serine and catalysis of ester formation. Our hypotheses were tested by biochemical analysis of various mutants, one of which shows a reversal of specificity from the wild type with respect to non-natural substrates. This change can be rationalized on the basis of our structural data. That this change in specificity is accompanied by no loss in activity suggests that AcsD and other members of the non-ribosomal peptide synthetase-independent siderophore superfamily may have biotransformation potential. Structural Basis for Acyl Acceptor Specificity in the Achromobactin Biosynthetic Enzyme AcsD.,Schmelz S, Botting CH, Song L, Kadi NF, Challis GL, Naismith JH J Mol Biol. 2011 Sep 23;412(3):495-504. Epub 2011 Aug 1. PMID:21835184 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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