Crystal structure of azoreductase AzoR from Escherichia coli

Abstract

Azoreductase AzoR is an oxidoreductase isolated from Escherichia coli as an enzyme responsible for the reduction of azo compounds. As the first step toward the elucidation of the molecular mechanism of function, we determined the three-dimensional structure of the enzyme by X-ray crystallography at 1.8 Å resolution. The crystal structure has revealed that AzoR is an FMN-containing and homodimeric enzyme. Each monomer consists of a twisted central parallel β-sheet surrounded on both sides by helices. The overall folding of the protein resembles NQO1, originally called DT-diaphorase [NAD(P)H: quinone reductase, EC 1.6.99.2], a mammalian FAD containing protein without significant sequence identity.