1jdr
Crystal Structure of a Proximal Domain Potassium Binding Variant of Cytochrome c Peroxidase
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OverviewOverview
Earlier work [Bonagura et al. (1996) Biochemistry 35, 6107] showed that the K+ site found in the proximal pocket of ascorbate peroxidase (APX) could be engineered into cytochrome c peroxidase (CCP). Binding of K+ at the engineered site results in a loss in activity and destabilization of the CCP compound I Trp191 cationic radical owing to long-range electrostatic effects. The engineered CCP mutant crystal structure has been refined to 1.5 A using data obtained at cryogenic temperatures which provides a more detailed basis for comparison with the naturally occurring K+ site in APX. The characteristic EPR signal associated with the Trp191 radical becomes progressively weaker as K+ is added, which correlates well with the loss in enzyme activity as [K+] is increased. These results coupled with stopped-flow studies support our earlier conclusions that the loss in activity and EPR signal is due to destabilization of the Trp191 cationic radical.
About this StructureAbout this Structure
1JDR is a Single protein structure of sequence from Saccharomyces cerevisiae with and as ligands. Active as Cytochrome-c peroxidase, with EC number 1.11.1.5 Full crystallographic information is available from OCA.
ReferenceReference
The effects of an engineered cation site on the structure, activity, and EPR properties of cytochrome c peroxidase., Bonagura CA, Sundaramoorthy M, Bhaskar B, Poulos TL, Biochemistry. 1999 Apr 27;38(17):5538-45. PMID:10220341
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