2ghk

Conformational mobility in the active site of a heme peroxidase

spinqualitylabelsall models 2ghk, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2ghk is a 1 chain structure with sequence from Glycine max. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.999Å Ligands: CYN, HEM, K Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q43758_SOYBN 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 PubMed Conformational mobility of the distal histidine residue has been implicated for several different heme peroxidase enzymes, but unambiguous structural evidence is not available. In this work, we present mechanistic, spectroscopic, and structural evidence for peroxide- and ligand-induced conformational mobility of the distal histidine residue (His-42) in a site-directed variant of ascorbate peroxidase (W41A). In this variant, His-42 binds "on" to the heme in the oxidized form, duplicating the active site structure of the cytochromes b but, in contrast to the cytochromes b, is able to swing "off" the iron during catalysis. This conformational flexibility between the on and off forms is fully reversible and is used as a means to overcome the inherently unreactive nature of the on form toward peroxide, so that essentially complete catalytic activity is maintained. Contrary to the widely adopted view of heme enzyme catalysis, these data indicate that strong coordination of the distal histidine to the heme iron does not automatically undermine catalytic activity. The data add a new dimension to our wider appreciation of structure/activity correlations in other heme enzymes. Conformational mobility in the active site of a heme peroxidase.,Badyal SK, Joyce MG, Sharp KH, Seward HE, Mewies M, Basran J, Macdonald IK, Moody PC, Raven EL J Biol Chem. 2006 Aug 25;281(34):24512-20. Epub 2006 Jun 7. PMID:16762924 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ascorbate peroxidase 3D structures

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