5CCP
HISTIDINE 52 IS A CRITICAL RESIDUE FOR RAPID FORMATION OF CYTOCHROME C PEROXIDASE COMPOUND I
Summary for 5CCP
Entry DOI | 10.2210/pdb5ccp/pdb |
Related | 1BEJ 1BEM 1BEQ 1BES 1CCP 1CPD 1CPE 1CPF 1CPG 2CCP 3CCP 4CCP 6CCP 7CCP |
Descriptor | CYTOCHROME C PEROXIDASE, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total) |
Functional Keywords | oxidoreductase |
Biological source | Saccharomyces cerevisiae (baker's yeast) |
Cellular location | Mitochondrion matrix: P00431 |
Total number of polymer chains | 1 |
Total formula weight | 34361.11 |
Authors | Brown, K.,Shaw, A.,Miller, M.A.,Kraut, J. (deposition date: 1993-06-07, release date: 1993-10-31, Last modification date: 2024-03-06) |
Primary citation | Erman, J.E.,Vitello, L.B.,Miller, M.A.,Shaw, A.,Brown, K.A.,Kraut, J. Histidine 52 is a critical residue for rapid formation of cytochrome c peroxidase compound I. Biochemistry, 32:9798-9806, 1993 Cited by PubMed Abstract: The crystal structure and reactivity with hydrogen peroxide are reported for a mutant of a cloned cytochrome c peroxidase [CcP(MI)], in which the conserved distal His (His-52) is replaced with Leu. The reaction of the H52L enzyme with peroxide was examined as a function of pH in 0.1 M phosphate buffers and buffers in which nitrate was used to adjust the ionic strength. The pH-independent bimolecular rate constant for the reaction of H52L with peroxide was 731 +/- 44 and 236 +/- 14 M-1 s-1 in phosphate and nitrate-containing buffers, respectively. This represents a 10(5)-fold decrease in rate relative to the CcP(MI) parent under comparable conditions. Single-crystal diffraction studies showed that no dramatic changes in the structure or in the accessibility of the heme binding site were caused by the mutation. Rather, the mutation caused significant structural changes only at residue 52 and the nearby active-site water molecules. The residual reactivity of the H52L enzyme with peroxide was pH- and buffer-dependent. In nitrate-containing buffer, the apparent bimolecular rate constant for the reaction with peroxide decreased with decreasing pH; the loss of reactivity correlated with protonation of a group with an apparent pKA = 4.5. Protonation of the group caused a loss of reactivity with peroxide. This is in contrast to the CcP(MI) parent enzyme, as well as all other mutants that have been examined, where the loss of reactivity correlates with protonation of an enzyme group with an apparent pKA = 5.4.(ABSTRACT TRUNCATED AT 250 WORDS) PubMed: 8396972DOI: 10.1021/bi00088a035 PDB entries with the same primary citation |
Experimental method | X-RAY DIFFRACTION (2.2 Å) |
Structure validation
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