3wy0 | pdb_00003wy0

The I375W mutant of CsyB complexed with CoA-SH

spinqualitylabelsall models 3wy0, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3wy0 is a 2 chain structure with sequence from Aspergillus oryzae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.001Å Ligands: COA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CSYB_ASPOR Acylalkylpyrone synthase that catalyzes not only the polyketide chain elongation but also the one-pot condensation of two beta-ketoacyl units to produce the 3-acyl-4-hydroxy-6-alkyl-alpha-pyrone (AcAP) scaffold, a precursor of csypyrone B (PubMed:20471846, PubMed:23290452, PubMed:24011646, PubMed:24895122, PubMed:25564614) (Probable). The enzyme reaction is initiated by the loading of acetoacetyl-CoA onto Cys-155, and subsequent thioester bond cleavage by the nucleophilic water generates the beta-keto acid intermediate, which is placed within a pocket (PubMed:25564614). The second beta-ketoacyl unit is then produced by polyketide chain elongation of fatty acyl-CoA with one molecule of malonyl-CoA, and the condensation with the beta-ketoacid generates the final products (PubMed:24895122, PubMed:25564614). Csypyrone B1 is the major product and contains a propanoic acid side-chain, whereas csypyrones B2 and B3 are minor compounds that contain butyric or pentanoic acid side-chains, respectively (PubMed:20471846, PubMed:23290452, PubMed:24011646). Publication Abstract from PubMed The acylalkylpyrone synthase CsyB from Aspergillus oryzae catalyzes the one-pot formation of the 3-acyl-4-hydroxy-6-alkyl-alpha-pyrone scaffold from acetoacetyl-CoA, fatty acyl-CoA, and malonyl-CoA. This is the first type III polyketide synthase that performs not only the polyketide chain elongation but also the condensation of two beta-ketoacyl units. The crystal structures of wild-type CsyB and its I375F and I375W mutants were solved at 1.7-, 2.3-, and 2.0-A resolutions, respectively. The crystal structures revealed a unique active site architecture featuring a hitherto unidentified novel pocket for accommodation of the acetoacetyl-CoA starter in addition to the conventional elongation/cyclization pocket with the Cys-His-Asn catalytic triad and the long hydrophobic tunnel for binding the fatty acyl chain. The structures also indicated the presence of a putative nucleophilic water molecule activated by the hydrogen bond networks with His-377 and Cys-155 at the active site center. Furthermore, an in vitro enzyme reaction confirmed that the (18)O atom of the H2(18)O molecule is enzymatically incorporated into the final product. These observations suggested that the enzyme reaction is initiated by the loading of acetoacetyl-CoA onto Cys-155, and subsequent thioester bond cleavage by the nucleophilic water generates the beta-keto acid intermediate, which is placed within the novel pocket. The second beta-ketoacyl unit is then produced by polyketide chain elongation of fatty acyl-CoA with one molecule of malonyl-CoA, and the condensation with the beta-keto acid generates the final products. Indeed, steric modulation of the novel pocket by the structure-based I375F and I375W mutations resulted in altered specificities for the chain lengths of the substrates. Structural basis for the formation of acylalkylpyrones from two beta-ketoacyl units by the fungal type III polyketide synthase CsyB.,Mori T, Yang D, Matsui T, Hashimoto M, Morita H, Fujii I, Abe I J Biol Chem. 2015 Feb 20;290(8):5214-25. doi: 10.1074/jbc.M114.626416. Epub 2015 , Jan 6. PMID:25564614 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

Proteopedia Page Contributors and Editors (what is this?)

OCA