1d7c
From Proteopedia
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CYTOCHROME DOMAIN OF CELLOBIOSE DEHYDROGENASE, PH 4.6
Overview
BACKGROUND: The fungal oxidoreductase cellobiose dehydrogenase (CDH), degrades both lignin and cellulose, and is the only known extracellular, flavocytochrome. This haemoflavoenzyme has a multidomain organisation with, a b-type cytochrome domain linked to a large flavodehydrogenase domain., The two domains can be separated proteolytically to yield a functional, cytochrome and a flavodehydrogenase. Here, we report the crystal structure, of the cytochrome domain of CDH. RESULTS: The crystal structure of the, b-type cytochrome domain of CDH from the wood-degrading fungus, Phanerochaete chrysosporium has been determined at 1.9 A resolution using, multiple isomorphous replacement including anomalous scattering, information. Three models of the cytochrome have been refined: the in, vitro prepared cytochrome in its redox-inactive state (pH 7.5) and, redox-active state (pH 4.6), as well as the naturally occurring cytochrome, fragment. CONCLUSIONS: The 190-residue long cytochrome domain of CDH folds, as a beta sandwich with the topology of the antibody Fab V(H) domain. The, haem iron is ligated by Met65 and His163, which confirms previous results, from spectroscopic studies. This is only the second example of a b-type, cytochrome with this ligation, the first being cytochrome b(562). The, haem-propionate groups are surface exposed and, therefore, might play a, role in the association between the cytochrome and flavoprotein domain, and in interdomain electron transfer. There are no large differences in, overall structure of the cytochrome at redox-active pH as compared with, the inactive form, which excludes the possibility that pH-dependent redox, inactivation results from partial denaturation. From the electron-density, map of the naturally occurring cytochrome, we conclude that it corresponds, to the proteolytically prepared cytochrome domain.
About this Structure
1D7C is a Single protein structure of sequence from Phanerochaete chrysosporium with CD, HEM and 1PG as ligands. Active as Deleted entry, with EC number 1.1.3.25 Full crystallographic information is available from OCA.
Reference
A new scaffold for binding haem in the cytochrome domain of the extracellular flavocytochrome cellobiose dehydrogenase., Hallberg BM, Bergfors T, Backbro K, Pettersson G, Henriksson G, Divne C, Structure. 2000 Jan 15;8(1):79-88. PMID:10673428
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