1x8k | pdb_00001x8k

Crystal structure of retinol dehydratase in complex with anhydroretinol and inactive cofactor PAP

spinqualitylabelsall models 1x8k, resolution 2.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1x8k is a 2 chain structure with sequence from Spodoptera frugiperda. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.75Å Ligands: A3P, ANR, CA, EMC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q26490_SPOFR 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 structure of retinol dehydratase (DHR) from Spodoptera frugiperda, a member of the sulfotransferase superfamily, in complexes with the inactive form of the cofactor PAP 3'-phosphoadenosine 5'-phosphate (PAP) and (1) the product of the reaction with retinol anhydroretinol (AR), (2) the retinoid inhibitor all-trans-4-oxoretinol (OR), and (3) the potent steroid inhibitor androsterone (AND) have been determined and compared to the enzyme complex with PAP and retinol. The structures show that the geometry of the active-site amino acids is largely preserved in the various complexes. However, the beta-ionone rings of the retinoids are oriented differently with respect to side chains that have been shown to be important for the enzymatic reaction. In addition, the DHR:PAP:AND complex reveals a novel mode for steroid binding that contrasts significantly with that for steroid binding in other sulfotransferases. The molecule is displaced and rotated approximately 180 degrees along its length so that there is no acceptor hydroxyl in close proximity to the site of sulfate transfer. This observation explains why steroids are potent inhibitors of retinol dehydratase activity, rather than substrates for sulfonation. Most of the steroid-protein contacts are provided by the alpha-helical cap that distinguishes this member of the superfamily. This observation suggests that in addition to providing a chemical environment that promotes the dehydration of a sulfonated intermediate, the cap may also serve to minimize a promiscuous sulfotransferases activity. The structures of the unique sulfotransferase retinol dehydratase with product and inhibitors provide insight into enzyme mechanism and inhibition.,Pakhomova S, Buck J, Newcomer ME Protein Sci. 2005 Jan;14(1):176-82. Epub 2004 Dec 2. PMID:15608121 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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