1coy
From Proteopedia
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| , resolution 1.8Å | |||||||
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| Ligands: | , | ||||||
| Activity: | Cholesterol oxidase, with EC number 1.1.3.6 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURE OF CHOLESTEROL OXIDASE COMPLEXED WITH A STEROID SUBSTRATE. IMPLICATIONS FOR FAD DEPENDENT ALCOHOL OXIDASES
Overview
Cholesterol 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)
About this Structure
1COY is a Single protein structure of sequence from Brevibacterium sterolicum. Full crystallographic information is available from OCA.
Reference
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
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