Might be a heme chaperone; in E.coli heme binds independently of binding to [4Fe-4S] or S-adenosyl-L-methionine. Belongs to the anaerobic coproporphyrinogen-III oxidase family. HemW subfamily. Pro-13, Tyr-17 and His-20 are present instead of the conserved Cys which are required to bind a 4Fe-4S-S-AdoMet cluster, as occurs with other proteins of this family. This protein may be an inactive homolog.