2q34

Crystal Structure of the ECH2 decarboxylase domain of CurF from Lyngbya majuscula, rhombohedral crystal form

spinqualitylabelsall models 2q34, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2q34 is a 1 chain structure with sequence from Moorena producens 19L. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.85Å Ligands: MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q6DNE7_9CYAN 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 Curacin A is a mixed polyketide/nonribosomal peptide possessing anti-mitotic and anti-proliferative activity. In the biosynthesis of curacin A, the N-terminal domain of the CurF multifunctional protein catalyzes decarboxylation of 3-methylglutaconyl-acyl carrier protein (ACP) to 3-methylcrotonyl-ACP, the postulated precursor of the cyclopropane ring of curacin A. This decarboxylase is encoded within an "HCS cassette" that is used by several other polyketide biosynthetic systems to generate chemical diversity by introduction of a beta-branch functional group to the natural product. The crystal structure of the CurF N-terminal ECH(2) domain establishes that the protein is a crotonase superfamily member. Ala(78) and Gly(118) form an oxyanion hole in the active site that includes only three polar side chains as potential catalytic residues. Site-directed mutagenesis and a biochemical assay established critical functions for His(240) and Lys(86), whereas Tyr(82) was nonessential. A decarboxylation mechanism is proposed in which His(240) serves to stabilize the substrate carboxylate and Lys(86) donates a proton to C-4 of the acyl-ACP enolate intermediate to form the Delta(2) unsaturated isopentenoyl-ACP product. The CurF ECH(2) domain showed a 20-fold selectivity for ACP-over CoA-linked substrates. Specificity for ACP-linked substrates has not been reported for any other crotonase superfamily decarboxylase. Tyr(73) may select against CoA-linked substrates by blocking a contact of Arg(38) with the CoA adenosine 5'-phosphate. Crystal structure of the ECH2 catalytic domain of CurF from Lyngbya majuscula. Insights into a decarboxylase involved in polyketide chain beta-branching.,Geders TW, Gu L, Mowers JC, Liu H, Gerwick WH, Hakansson K, Sherman DH, Smith JL J Biol Chem. 2007 Dec 7;282(49):35954-63. Epub 2007 Oct 10. PMID:17928301 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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