1kdg | pdb_00001kdg
Crystal structure of the flavin domain of cellobiose dehydrogenase
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Overview
Cellobiose dehydrogenase (CDH) participates in the degradation of cellulose and lignin. The protein is an extracellular flavocytochrome with a b-type cytochrome domain (CYT(cdh)) connected to a flavodehydrogenase domain (DH(cdh)). DH(cdh) catalyses a two-electron oxidation at the anomeric C1 position of cellobiose to yield cellobiono-1,5-lactone, and the electrons are subsequently transferred from DH(cdh) to an acceptor, either directly or via CYT(cdh). Here, we describe the crystal structure of Phanerochaete chrysosporium DH(cdh) determined at 1.5 A resolution. DH(cdh) belongs to the GMC family of oxidoreductases, which includes glucose oxidase (GOX) and cholesterol oxidase (COX); however, the sequence identity with members of the family is low. The overall fold of DH(cdh) is p-hydroxybenzoate hydroxylase-like and is similar to, but also different from, that of GOX and COX. It is partitioned into an FAD-binding subdomain of alpha/beta type and a substrate-binding subdomain consisting of a seven-stranded beta sheet and six helices. Docking of CYT(cdh) and DH(cdh) suggests that CYT(cdh) covers the active-site entrance in DH(cdh), and that the resulting distance between the cofactors is within acceptable limits for inter-domain electron transfer. Based on docking of the substrate, cellobiose, in the active site of DH(cdh), we propose that the enzyme discriminates against glucose by favouring interaction with the non-reducing end of cellobiose.
About this Structure
1KDG is a Single protein structure of sequence from Phanerochaete chrysosporium with NAG, MAN, HG, 6FA, EMT and S as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of the flavoprotein domain of the extracellular flavocytochrome cellobiose dehydrogenase., Hallberg BM, Henriksson G, Pettersson G, Divne C, J Mol Biol. 2002 Jan 18;315(3):421-34. PMID:11786022
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