PDBsum entry 2cep

Oxidoreductase(h2o2(a))

PDB id: 2cep

Contents

Protein chain

293 a.a. *

Ligands

HEM

Waters ×225

* Residue conservation analysis

PDB id:

2cep

Name:

Oxidoreductase(h2o2(a))

Title:

Role of met-230 in intramolecular electron transfer between the oxyferryl heme and trp 191 in cytochromE C peroxidase compound ii

Structure:

CytochromE C peroxidase. Chain: a. Engineered: yes

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 4932

Resolution:

2.20Å R-factor: 0.167

Authors:

G.W.Han,M.A.Miller,J.Kraut

Key ref:

R.Q.Liu et al. (1994). Role of methionine 230 in intramolecular electron transfer between the oxyferryl heme and tryptophan 191 in cytochrome c peroxidase compound II. Biochemistry, 33, 8678-8685. PubMed id: 8038157 DOI: 10.1021/bi00195a008

Date:

31-May-94 Release date: 31-Aug-94

Protein chain

P00431  (CCPR_YEAST) -  Cytochrome c peroxidase, mitochondrial from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 361 a.a.

Struc: 293 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.1.11.1.5 - cytochrome-c peroxidase.
• Reaction: 2 Fe(II)-[cytochrome c] + H2O2 + 2 H⁺ = 2 Fe(III)-[cytochrome c] + 2 H2O
• Cofactor: Heme

Heme (Bound ligand (Het Group name = HEM) matches with 95.45% similarity)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1021/bi00195a008

Biochemistry 33:8678-8685 (1994)

PubMed id: 8038157

Role of methionine 230 in intramolecular electron transfer between the oxyferryl heme and tryptophan 191 in cytochrome c peroxidase compound II.

R.Q.Liu, M.A.Miller, G.W.Han, S.Hahm, L.Geren, S.Hibdon, J.Kraut, B.Durham, F.Millett.

ABSTRACT

The kinetics of electron transfer from cytochrome c (CC) to yeast cytochrome c peroxidase (CcP) compound I were studied by flash photolysis and stopped-flow spectroscopy. Flash photolysis studies employed horse CC derivatives labeled at specific lysine amino groups with (dicarboxybipyridine)bis-(bipyridine)ruthenium (Ru-CC). Initial electron transfer from Ru-CC reduced the indole radical on Trp-191 of CcP compound I [CMPI(IV,R.)], producing CMPII(IV,R). This reaction was biphasic for each of several Ru-CC derivatives, with rate constants which varied according to the position of the Ru label. For Ru-27-CC labeled at lysine 27, rate constants of 43,000 and 1600 s-1 were observed at pH 5.0 in 2 mM acetate. After reduction of the indole radical by Ru-CC, intramolecular electron transfer from Trp-191 to the oxyferryl heme in CMPII(IV,R) was observed, producing CMPII(III,R.). The rate constant and extent of this intramolecular electron transfer reaction were independent of both the protein concentration and the Ru-CC derivative employed. The rate constant decreased from 1100 s-1 at pH 5 to 550 s-1 at pH 6, while the extent of conversion of CMPII(IV,R) to CMPII(III,R.) decreased from 56% at pH 5 to 29% at pH 6. The reaction was not detected at pH 7.0 and above. The pH dependence of the rate and extent of this internal electron transfer reaction paralleled the pH dependence of the rate of bimolecular reduction of CMPII(IV,R) by native horse CC measured by stopped-flow spectroscopy at high ionic strength.(ABSTRACT TRUNCATED AT 250 WORDS)