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


Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Rudolph, MJ; Johnson, JL; Rajagopalan, KV; Kisker, C

Published Date

  • July 2003

Published In

Volume / Issue

  • 59 / Pt 7

Start / End Page

  • 1183 - 1191

PubMed ID

  • 12832761

Pubmed Central ID

  • 12832761

International Standard Serial Number (ISSN)

  • 0907-4449

Digital Object Identifier (DOI)

  • 10.1107/s0907444903009934


  • eng

Conference Location

  • United States