PDBsum entry 1mj4

Oxidoreductase

PDB id: 1mj4

Contents

Protein chain

80 a.a. *

Ligands

SO4

HEM

GOL

Waters ×117

* Residue conservation analysis

PDB id:

1mj4

Name:

Oxidoreductase

Title:

Crystal structure analysis of the cytochrome b5 domain of human sulfite oxidase

Structure:

Sulfite oxidase. Chain: a. Fragment: cytochrome b5 domain, residues 22-103 of sws p51687. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.20Å R-factor: 0.120 R-free: 0.139

Authors:

M.J.Rudolph,J.L.Johnson,K.V.Rajagopalan,C.Kisker

Key ref:

M.J.Rudolph et al. (2003). The 1.2 A structure of the human sulfite oxidase cytochrome b(5) domain. Acta Crystallogr D Biol Crystallogr, 59, 1183-1191. PubMed id: 12832761 DOI: 10.1107/S0907444903009934

Date:

26-Aug-02 Release date: 12-Sep-02

Protein chain

P51687  (SUOX_HUMAN) -  Sulfite oxidase, mitochondrial from Homo sapiens

Seq: 545 a.a.

Struc: 80 a.a.

Enzyme reactions

• Enzyme class: E.C.1.8.3.1 - sulfite oxidase.
• Reaction: sulfite + O2 + H2O = sulfate + H2O2

sulfite + O2 + H2O = sulfate + H2O2 (Bound ligand (Het Group name = SO4) corresponds exactly)

• Cofactor: Heme; Mo cation

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

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

reference

DOI no: 10.1107/S0907444903009934

Acta Crystallogr D Biol Crystallogr 59:1183-1191 (2003)

PubMed id: 12832761

The 1.2 A structure of the human sulfite oxidase cytochrome b(5) domain.

M.J.Rudolph, J.L.Johnson, K.V.Rajagopalan, C.Kisker.

ABSTRACT

The molybdenum- and iron-containing enzyme sulfite oxidase catalyzes the physiologically vital oxidation of sulfite to sulfate. Sulfite oxidase contains three domains: an N-terminal cytochrome b(5) domain, a central domain harboring the molybdenum cofactor (Moco) and a C-terminal dimerization domain. Oxidation of the substrate sulfite is coupled to the transfer of two electrons to the molybdenum cofactor. Subsequently, these electrons are passed on, one at a time, to the b(5) heme of sulfite oxidase and from there to the soluble electron carrier cytochrome c. The crystal structure of the oxidized human sulfite oxidase cytochrome b(5) domain has been determined at 1.2 A resolution and has been refined to a crystallographic R factor of 0.107 (R(free) = 0.137). A comparison of this structure with other b(5)-type cytochromes reveals distinct structural features present in the sulfite oxidase b(5) domain which promote optimal electron transport between the Moco of sulfite oxidase and the heme of cytochrome c.

Selected figure(s)

Figure 1.
Figure 1 Sulfite oxidase-catalyzed reaction. The reaction consists of the oxidation of sulfite to sulfate coupled with the subsequent reduction of two equivalents of ferricytochrome c to ferrocytochrome c.

Figure 8.
Figure 8 Representation of the HSO b[5] (a) and CYT b[5] (b) heme axial ligand environments. The heme is shown in all-bonds representation, with the iron in green. The axial histidines are in all-bonds representation, with the red dots depicting the interactions between the Fe atom and the N 2 atoms of the axial histidines as well as the hydrogen bonds between the carbonyl O atoms and the N 1 atoms from the axial histidines.

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2003, 59, 1183-1191) copyright 2003.

Figures were selected by an automated process.