1krj

Engineering Calcium-binding site into Cytochrome c Peroxidase (CcP)

spinqualitylabelsall models 1krj, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1krj is a 1 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: HEM, K Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 PubMed We have previously shown that the K(+) site found in ascorbate peroxidase can be successfully engineered into the closely homologous peroxidase, cytochrome c peroxidase (CCP) (Bonagura, C. A. , Sundaramoorthy, M., Pappa, H. S., Patterson, W. R., and Poulos, T. L. (1996) Biochemistry 35, 6107-6115; Bonagura, C. A., Sundaramoorthy, M., Bhaskar, B., and Poulos, T. L. (1999) Biochemistry 38, 5538-5545). All other peroxidases bind Ca(2+) rather than K(+). Using the K(+)-binding CCP mutant (CCPK2) as a template protein, together with observations from structural modeling, mutants were designed that should bind Ca(2+) selectively. The crystal structure of the first generation mutant, CCPCA1, showed that a smaller cation, perhaps Na(+), is bound instead of Ca(2+). This is probably because the full eight-ligand coordination sphere did not form owing to a local disordering of one of the essential cation ligands. Based on these observations, a second mutant, CCPCA2, was designed. The crystal structure showed Ca(2+) binding in the CCPCA2 mutant and a well ordered cation-binding loop with the full complement of eight protein to cation ligands. Because cation binding to the engineered loop results in diminished CCP activity and destabilization of the essential Trp(191) radical as measured by EPR spectroscopy, these measurements can be used as sensitive methods for determining cation-binding selectivity. Both activity and EPR titration studies show that CCPCA2 binds Ca(2+) more effectively than K(+), demonstrating that an iterative protein engineering-based approach is important in switching protein cation selectivity. Conversion of an engineered potassium-binding site into a calcium-selective site in cytochrome c peroxidase.,Bonagura CA, Bhaskar B, Sundaramoorthy M, Poulos TL J Biol Chem. 1999 Dec 31;274(53):37827-33. PMID:10608846 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome c peroxidase 3D structures

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