3cox | pdb_00003cox
CRYSTAL STRUCTURE OF CHOLESTEROL OXIDASE COMPLEXED WITH A STEROID SUBSTRATE. IMPLICATIONS FOR FAD DEPENDENT ALCOHOL OXIDASES
Structural highlights
Function[CHOD_BREST] Catalyzes the oxidation and isomerization of cholesterol to cholestenone (4-cholesten-3-one), which is an initial step in the cholesterol degradation process. 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 PubMedCholesterol oxidase from Brevibacterium sterolicum is a flavin-dependent enzyme that catalyzes the oxidation and isomerization of 3 beta-hydroxy steroids with a double bond at delta 5-delta 6 of the steroid ring backbone. The crystal structure of the free enzyme in the absence of a steroid substrate has previously been determined. In this paper we report the crystal structure of the complex of cholesterol oxidase with the steroid substrate dehydroisoandrosterone, refined at 1.8-A resolution. The final crystallographic R-value is 15.7% for all reflections between 10.0- and 1.8-A resolution. The steroid is buried within the protein in an internal cavity which, in the free enzyme crystal structure, was occupied by a lattice of water molecules. The conformations of a number of side chains lining the active-site cavity have changed in order to accommodate the steroid substrate. A loop region of the structure between residues 70 and 90 differs significantly between the substrate-free and substrate-bound forms of the enzyme, presumably to facilitate binding of the steroid. The hydroxyl group of the steroid substrate is hydrogen-bonded to both the flavin ring system of the FAD cofactor and a bound water molecule. FAD-dependent cholesterol oxidase shares significant structural homology with another flavoenzyme, glucose oxidase, suggesting that it might also be a member of the glucose-methanol-choline (GMC) oxidoreductase family. Although there is only limited sequence homology, a superposition of these two structures reveals a conserved histidine residue within hydrogen-bonding distance of the active-site water molecule.(ABSTRACT TRUNCATED AT 250 WORDS) Crystal structure of cholesterol oxidase complexed with a steroid substrate: implications for flavin adenine dinucleotide dependent alcohol oxidases.,Li J, Vrielink A, Brick P, Blow DM Biochemistry. 1993 Nov 2;32(43):11507-15. PMID:8218217[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||||
