4k00

Crystal structure of Slr0204, a 1,4-dihydroxy-2-naphthoyl-CoA thioesterase from Synechocystis

spinqualitylabelsall models 4k00, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4k00 is a 2 chain structure with sequence from Synechocystis sp. PCC 6803 substr. Kazusa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EDO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DNCH_SYNY3 Catalyzes the specific hydrolysis of 1,4-dihydroxy-2-naphthoyl-CoA (DHNA-CoA) to 1,4-dihydroxy-2-naphthoate (DHNA), a reaction involved in phylloquinone (vitamin K1) biosynthesis. Is not active on benzoyl-CoA, phenylacetyl-CoA and aliphatic acyl-CoA thioesters. Publication Abstract from PubMed The synthesis of phylloquinone (vitamin K1) in photosynthetic organisms requires a thioesterase that hydrolyzes 1,4-dihydroxy-2-naphthoyl-CoA (DHNA-CoA) to release 1,4-dihydroxy-2-naphthoate (DHNA). Cyanobacteria and plants contain distantly related hotdog-fold thioesterases that catalyze this reaction, although the structural basis of these convergent enzymatic activities is unknown. To investigate this, the crystal structures of hotdog-fold DHNA-CoA thioesterases from the cyanobacterium Synechocystis (Slr0204) and the flowering plant Arabidopsis thaliana (AtDHNAT1) were determined. These enzymes form distinct homotetramers and use different active sites to catalyze hydrolysis of DHNA-CoA, similar to the 4-hydroxybenzoyl-CoA (4-HBA-CoA) thioesterases from Pseudomonas and Arthrobacter. Like the 4-HBA-CoA thioesterases, the DHNA-CoA thioesterases contain either an active-site aspartate (Slr0204) or glutamate (AtDHNAT1) that are predicted to be catalytically important. Computational modeling of the substrate-bound forms of both enzymes indicates the residues that are likely to be involved in substrate binding and catalysis. Both enzymes are selective for DHNA-CoA as a substrate, but this selectivity is achieved using divergent predicted binding strategies. The Slr0204 binding pocket is predominantly hydrophobic and closely conforms to DHNA, while that of AtDHNAT1 is more polar and solvent-exposed. Considered in light of the related 4-HBA-CoA thioesterases, these structures indicate that hotdog-fold thioesterases using either an active-site aspartate or glutamate diverged into distinct clades prior to the evolution of strong substrate specificity in these enzymes. Functional convergence of structurally distinct thioesterases from cyanobacteria and plants involved in phylloquinone biosynthesis.,Furt F, Allen WJ, Widhalm JR, Madzelan P, Rizzo RC, Basset G, Wilson MA Acta Crystallogr D Biol Crystallogr. 2013 Oct;69(Pt 10):1876-88. doi:, 10.1107/S0907444913015771. Epub 2013 Sep 20. PMID:24100308 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thioesterase 3D structures

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