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Title: HemQ: An iron-coproporphyrin oxidative decarboxylase for protoheme synthesis in Firmicutes and Actinobacteria

Genes for chlorite dismutase-like proteins are found widely among heme-synthesizing bacteria and some Archaea. It is now known that among the Firmicutes and Actinobacteria these proteins do not possess chlorite dismutase activity but instead are essential for heme synthesis. These proteins, named HemQ, are ironcoproporphyrin (coproheme) decarboxylases that catalyze the oxidative decarboxylation of coproheme III into protoheme IX. As purified, HemQs do not contain bound heme, but readily bind exogeneously supplied heme with low micromolar affinity. We find that the heme-bound form of HemQ has low peroxidase activity and in the presence of peroxide the bound heme may be destroyed. Furthermore, it is possible that HemQ may serve a dual role as a decarboxylase in heme biosynthesis and a regulatory protein in heme homeostasis.
 [1] ;  [2]
  1. Univ. of Georgia, Athens, GA (United States). Inst. of Biomedical and Health Sciences
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Mathematics and Computer Science Division
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Archives of Biochemistry and Biophysics
Additional Journal Information:
Journal Volume: 574; Journal Issue: C; Journal ID: ISSN 0003-9861
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE; National Institutes of Health (NIH)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; HemQ; Heme synthesis; coproheme decarboxylase; chlorite dismutase-like protein