InterPro domain: IPR004559

Proteins in this entry include HemW (also known as oxygen-independent coproporphyrinogen-III oxidase-like protein). HemW is a heme chaperone catalyzing the insertion of heme into hemoproteins [ 1 ].

Experimentally determined examples of oxygen-independent coproporphyrinogen III oxidase, an enzyme that replaces HemF function under anaerobic conditions, belong to a family of proteins called HemN ( IPR004558 ). This family contains a closely related protein, shorter at the amino end and lacking the region containing the motif PYRT[SC]YP found in members of the hemN family. Several species, including Escherichia coli, Helicobacter pylori, Aquifex aeolicus, and Chlamydia trachomatis, have members of both this family and the Escherichia coli hemN family. The member of this family from Bacillus subtilis was shown to complement a hemF/hemN double mutant of Salmonella typhimurium and to prevent accumulation of coproporphyrinogen III under anaerobic conditions, but the exact role of this protein is still uncertain. It is found in a number of species that do not synthesize haem de novo .

1. The radical SAM protein HemW is a heme chaperone. J. Biol. Chem. 293, 2558-2572