PDBsum entry 1nx7

Electron transport

PDB id: 1nx7

Contents

Protein chain

82 a.a. *

Ligands

HEM

* Residue conservation analysis

PDB id:

1nx7

Name:

Electron transport

Title:

Solution structure of oxidized bovine microsomal cytochrome b5

Structure:

Cytochrome b5. Chain: a. Fragment: residues 3-84. Engineered: yes

Source:

Bos taurus. Cattle. Organism_taxid: 9913. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

30 models

Authors:

H.Wu,Q.Zang

Key ref:

Q.Zhang et al. (2004). The comparative study on the solution structures of the oxidized bovine microsomal cytochrome b5 and mutant V45H. Protein Sci, 13, 2161-2169. PubMed id: 15273310 DOI: 10.1110/ps.04721104

Date:

10-Feb-03 Release date: 15-Jun-04

Protein chain

P00171  (CYB5_BOVIN) -  Cytochrome b5 from Bos taurus

Seq: 134 a.a.

Struc: 82 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1110/ps.04721104

Protein Sci 13:2161-2169 (2004)

PubMed id: 15273310

The comparative study on the solution structures of the oxidized bovine microsomal cytochrome b5 and mutant V45H.

Q.Zhang, C.Cao, Z.Q.Wang, Y.H.Wang, H.Wu, Z.X.Huang.

ABSTRACT

A comparative study on the solution structures of bovine microsomal cytochrome b5 (Tb5) and the mutant V45H has been achieved by 1D and 2D 1H-NMR spectroscopy to clarify the differences in the solution conformations between these two proteins. The results reveal that the global folding of the V45H mutant in solution is unchanged, but the subtle changes exist in the orientation of the axial ligand His39, and heme vinyl groups. The side chain of His45 in V45H mutant extends to the outer edge of the heme pocket leaving a cavity at the site originally occupied by the inner methyl group of Val45 residue. In addition, the imidazole ring of axial ligand His39 rotates counterclockwise by approximately 3 degrees around the His-Fe-His axis, and the 4-heme vinyl group turns to the space vacated by the removed side chain due to the mutation. Furthermore, the helix III of the heme pocket undergoes outward displacement, while the linkage between helix II and III is shifted leftward. These observations are not only consistent with the pattern of the pseudocontact shifts of the heme protons, but also well account for the lower stability of V45H mutant against heat and urea.

Selected figure(s)

Figure 1.
Figure 1. Schematic representation of the short- and medium-range NOE connectivities of proteins: Tb5 (A) and the mutate V45H (B).

Figure 4.
Figure 4. The orientations of the heme moieties and heme vinyl groups in Tb5 and V45H.

The above figures are reprinted by permission from the Protein Society: Protein Sci (2004, 13, 2161-2169) copyright 2004.

Figures were selected by an automated process.