PDBsum entry 2bcn

Oxidoreductase/electron transfer

PDB id: 2bcn

Contents

Protein chains

294 a.a. *

108 a.a. *

Ligands

ZNH ×2

HEC

Waters ×547

* Residue conservation analysis

PDB id:

2bcn

Name:

Oxidoreductase/electron transfer

Title:

Solvent isotope effects on interfacial protein electron transfer between cytochromE C and cytochromE C peroxidase

Structure:

CytochromE C peroxidase. Chain: a, c. Engineered: yes. CytochromE C iso-1. Chain: b. Engineered: yes. Mutation: yes

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 4932. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: cyc1. Expression_system_taxid: 562

Biol. unit:

Trimer (from PQS)

Resolution:

1.70Å R-factor: 0.219 R-free: 0.230

Authors:

S.A.Kang,B.R.Crane

Key ref:

S.A.Kang et al. (2006). Solvent isotope effects on interfacial protein electron transfer in crystals and electrode films. J Am Chem Soc, 128, 2346-2355. PubMed id: 16478190 DOI: 10.1021/ja0557482

Date:

19-Oct-05 Release date: 28-Feb-06

Protein chains

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

Seq: 361 a.a.

Struc: 294 a.a.*

Protein chain

P00044  (CYC1_YEAST) -  Cytochrome c isoform 1 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 109 a.a.

Struc: 108 a.a.*

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

Enzyme reactions

• Enzyme class: Chains A, C: 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 = ZNH) matches with 95.45% similarity)

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

Added reference

DOI no: 10.1021/ja0557482

J Am Chem Soc 128:2346-2355 (2006)

PubMed id: 16478190

Solvent isotope effects on interfacial protein electron transfer in crystals and electrode films.

S.A.Kang, K.R.Hoke, B.R.Crane.

ABSTRACT

D(2)O-grown crystals of yeast zinc porphyrin substituted cytochrome c peroxidase (ZnCcP) in complex with yeast iso-1-cytochrome c (yCc) diffract to higher resolution (1.7 A) and pack differently than H(2)O-grown crystals (2.4-3.0 A). Two ZnCcP's bind the same yCc (porphyrin-to-porphyrin separations of 19 and 29 A), with one ZnCcP interacting through the same interface found in the H(2)O crystals. The triplet excited-state of at least one of the two unique ZnCcP's is quenched by electron transfer (ET) to Fe(III)yCc (k(e) = 220 s(-1)). Measurement of thermal recombination ET between Fe(II)yCc and ZnCcP+ in the D(2)O-treated crystals has both slow and fast components that differ by 2 orders of magnitude (k(eb)(1) = 2200 s(-1), k(eb)(2) = 30 s(-1)). Back ET in H(2)O-grown crystals is too fast for observation, but soaking H(2)O-grown crystals in D(2)O for hours generates slower back ET, with kinetics similar to those of the D(2)O-grown crystals (k(eb)(1) = 7000 s(-1), k(eb)(2) = 100 s(-1)). Protein-film voltammetry of yCc adsorbed to mixed alkanethiol monolayers on gold electrodes shows slower ET for D(2)O-grown yCc films than for H(2)O-grown films (k(H) = 800 s(-1); k(D) = 540 s(-1) at 20 degrees C). Soaking H(2)O- or D(2)O-grown films in the counter solvent produces an immediate inverse isotope effect that diminishes over hours until the ET rate reaches that found in the counter solvent. Thus, D(2)O substitution perturbs interactions and ET between yCc and either CcP or electrode films. The effects derive from slow exchanging protons or solvent molecules that in the crystal produce only small structural changes.