PDBsum entry 1f03

Electron transport

PDB id: 1f03

Contents

Protein chain

82 a.a. *

Ligands

HEM

* Residue conservation analysis

PDB id:

1f03

Name:

Electron transport

Title:

Solution structure of oxidized bovine microsomal cytochrome b5 mutant (e44a, e48a, e56a, d60a) and its interaction with cytochromE C

Structure:

Cytochrome b5. Chain: a. Engineered: yes. Mutation: yes

Source:

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

NMR struc:

1 models

Authors:

Y.B.Wu,J.Lu,C.M.Qian,W.X.Tang,E.C.Li,J.F.Wang,Y.H.Wang,W.H.Wang, J.X.Lu,Y.Xie,Z.X.Huang

Key ref:

Y.Wu et al. (2001). Solution structure of cytochrome b(5) mutant (E44/48/56A/D60A) and its interaction with cytochrome c. Eur J Biochem, 268, 1620-1630. PubMed id: 11248680 DOI: 10.1046/j.1432-1327.2001.02033.x

Date:

14-May-00 Release date: 21-Jun-00

Protein chain

P00171  (CYB5_BOVIN) -  Cytochrome b5 from Bos taurus

Seq: 134 a.a.

Struc: 82 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1046/j.1432-1327.2001.02033.x

Eur J Biochem 268:1620-1630 (2001)

PubMed id: 11248680

Solution structure of cytochrome b(5) mutant (E44/48/56A/D60A) and its interaction with cytochrome c.

Y.Wu, Y.Wang, C.Qian, J.Lu, E.Li, W.Wang, J.Lu, Y.Xie, J.Wang, D.Zhu, Z.Huang, W.Tang.

ABSTRACT

Using 1617 meaningful NOEs with 188 pseudocontact shifts, a family of 35 conformers of oxidized bovine microsomal cytochrome b5 mutant (E44/48/56A/D60A) has been obtained and is characterized by good resolution (rmsd to the mean structure are 0.047 +/- 0.007 nm and 0.095 +/- 0.008 nm for backbone and heavy atoms, respectively). The solution structure of the mutant, when compared with the X-ray structure of wild-type cytochrome b(5), has no significant changes in the whole folding and secondary structure. The binding between cytochrome b(5) and cytochrome c shows that the association constant of the mutant-cytochrome c complex is much lower than the one for wild-type complex (2.2 x 10(4) M(-1) vs. 5.1 x 10(3) M(-1)). The result suggests the four acidic residues have substantial effects on the formation of the complex between cytochrome b(5) and cytochrome c, and therefore it is concluded reasonably that the electrostatic interaction plays an important role in maintaining the stability and specificity of the complex formed. The competition between the ferricytochrome b(5) mutant and [Cr(oxalate)(3)](3-) for ferricytochrome c shows that site III of cytochrome c, which is a strong binding site to wild-type cytochrome b(5), still binds to the mutant with relatively weaker strength. Our results indicate that certain bonding geometries do occur in the interaction between the present mutant and cytochrome c and these geometries, which should be quite different from the ones of the Salemme and Northrup models.

Selected figure(s)

Figure 1.
Fig. 1. Schematic representation of the sequential and medium-range NOE connectivities involving NH, H , and H protons for the oxidized form of cyt b[5] mutant (E44/48/56A/D60A). The thickness of the bar indicates the intensity of NOEs.

Figure 4.
Fig. 4. Ribbon diagrams of the average minimized solution structures of the bovine oxidized cyt b[5] mutant and X-ray structure of wild-type cyt b[5] (A and B, respectively). A stereoview of the superimposed structures of cyt b[5] mutant (black line) and the wild-type (gray line) is shown (C).

The above figures are reprinted by permission from the Federation of European Biochemical Societies: Eur J Biochem (2001, 268, 1620-1630) copyright 2001.

Figures were selected by an automated process.