5CCP

HISTIDINE 52 IS A CRITICAL RESIDUE FOR RAPID FORMATION OF CYTOCHROME C PEROXIDASE COMPOUND I

5CCP の概要

• エントリーDOI: 10.2210/pdb5ccp/pdb
• 関連するPDBエントリー: 1BEJ 1BEM 1BEQ 1BES 1CCP 1CPD 1CPE 1CPF 1CPG 2CCP 3CCP 4CCP 6CCP 7CCP
• 分子名称: CYTOCHROME C PEROXIDASE, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: oxidoreductase
• 由来する生物種: Saccharomyces cerevisiae (baker's yeast)
• 細胞内の位置: Mitochondrion matrix: P00431
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 34361.11

構造登録者

Brown, K.,Shaw, A.,Miller, M.A.,Kraut, J. (登録日: 1993-06-07, 公開日: 1993-10-31, 最終更新日: 2024-03-06)

主引用文献

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

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: 8396972
DOI: 10.1021/bi00088a035

実験手法

X-RAY DIFFRACTION (2.2 Å)