PDBsum entry 1e8e

Oxidoreductase(cytochrome)

PDB id: 1e8e

Contents

Protein chain

124 a.a. *

Ligands

HEC

* Residue conservation analysis

PDB id:

1e8e

Name:

Oxidoreductase(cytochrome)

Title:

Solution structure of methylophilus methylotrophus cytochrome c''. Insights into the structural basis of haem-ligand detachment

Structure:

Cytochrome c''. Chain: a. Other_details: c-type cytochrome, fully oxidised form

Source:

Methylophilus methylotrophus. Bacterium w3a1. Organism_taxid: 17

NMR struc:

20 models

Authors:

L.Brennan,D.L.Turner,P.Fareleira,H.Santos

Key ref:

L.Brennan et al. (2001). Solution structure of Methylophilus methylotrophus cytochrome c": insights into the structural basis of haem-ligand detachment. J Mol Biol, 308, 353-365. PubMed id: 11327772 DOI: 10.1006/jmbi.2001.4600

Date:

20-Sep-00 Release date: 20-Sep-01

Protein chain

Q9RQB9  (CYCA_METME) -  Cytochrome c'' from Methylophilus methylotrophus

Seq: 144 a.a.

Struc: 124 a.a.

DOI no: 10.1006/jmbi.2001.4600

J Mol Biol 308:353-365 (2001)

PubMed id: 11327772

Solution structure of Methylophilus methylotrophus cytochrome c": insights into the structural basis of haem-ligand detachment.

L.Brennan, D.L.Turner, P.Fareleira, H.Santos.

ABSTRACT

Cytochrome c" from Methylophilus methylotrophus is a monohaem protein with 124 amino acid residues. The iron has two histidine ligands in the oxidised form, one of which detaches and picks up a proton when the protein is reduced. Thus, both forms are paramagnetic. The structure of the oxidised form in solution, determined from NMR data is presented. The family of structures has an average backbone rmsd value of 0.53 A, and a heavy atom rmsd value of 0.95 A, within a target function range of 32 %. This structure is related to class I cytochromes with an additional helix at the N terminus. The haem-binding site occurs in a domain essentially lacking secondary structure motifs and the axial histidinyl residues were found in an unusual near perpendicular orientation. Moreover, a disulfide bridge is present, an uncommon structural feature among c-type cytochromes. The disulfide bridge, linking cysteine residues 96 and 104, forms a loop that confers rigidity and is essential to the detachment of the axial histidine (His95) as demonstrated by chemical disruption of the S-S bond. A route for protonation of the distal histidine involving haem propionate 17 is proposed and discussed in the light of available models for complex membrane proton pumps.

Selected figure(s)

Figure 1.
Figure 1. The number of non-redundant upper distance limits per residue. White indicates intra-residue restraints, light and dark grey represent sequential and medium range restraints, respectively, and black represents long range restraints.

Figure 6.
Figure 6. Haem group, axial ligands and aromatic residues in the haem pocket of cytochrome c'' of the best structure. Two views, related by a 90 ° rotation about the z-axis, are shown to make the distribution of aromatic groups clear.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2001, 308, 353-365) copyright 2001.

Figures were selected by an automated process.