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Crystal Structure of a Proximal Domain Potassium Binding Variant of Cytochrome c PeroxidaseCrystal Structure of a Proximal Domain Potassium Binding Variant of Cytochrome c Peroxidase
Structural highlights
Function[CCPR_YEAST] Destroys radicals which are normally produced within the cells and which are toxic to biological systems. 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 PubMedEarlier 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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