Molecular dissection of a putative iron reductase from Desulfotomaculum reducens MI-1

Zhi Li; David D Kim; Ornella D Nelson; Anne E Otwell; Ruth E Richardson; Stephen J Callister; Hening Lin

doi:10.1016/j.bbrc.2015.10.016

Molecular dissection of a putative iron reductase from Desulfotomaculum reducens MI-1

Biochem Biophys Res Commun. 2015 Nov 20;467(3):503-8. doi: 10.1016/j.bbrc.2015.10.016. Epub 2015 Oct 8.

Authors

Zhi Li¹, David D Kim¹, Ornella D Nelson¹, Anne E Otwell², Ruth E Richardson³, Stephen J Callister⁴, Hening Lin⁵

Affiliations

¹ Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
² Department of Microbiology, Cornell University, Ithaca, NY 14853, USA.
³ School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA.
⁴ Pacific Northwest National Laboratory, Richland, WA 99354, USA.
⁵ Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA; Howard Hughes Medical Institute, USA. Electronic address: hl379@cornell.edu.

Abstract

Desulfotomaculum reducens MI-1 is a Firmicute strain capable of reducing a variety of heavy metal ions and has a great potential in heavy metal bioremediation. We recently identified Dred_2421 as a potential iron reductase through proteomic study of D. reducens. The current study examines its iron-reduction mechanism. Dred_2421, like its close homolog from Escherichia coli (2, 4-dienoyl-CoA reductase), has an FMN-binding N-terminal domain (NTD), an FAD-binding C-terminal domain (CTD), and a 4Fe-4S cluster between the two domains. To understand the mechanism of the iron-reduction activity and the role of each domain, we generated a series of variants for each domain and investigated their iron-reduction activity. Our results suggest that CTD is the main contributor of the iron-reduction activity, and that NTD and the 4Fe-4S cluster are not directly involved in such activity. This study provides a mechanistic understanding of the iron-reductase activity of Dred_2421 and may also help to elucidate other physiological activities this enzyme may have.

Keywords: Desulfotomaculum; Iron reduction; NADH; NADH:Flavin oxidoreductase; Old yellow enzymes; pfam00724.

Publication types

Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Desulfotomaculum / enzymology*
FMN Reductase / genetics
FMN Reductase / metabolism*

Substances

FMN Reductase
ferric citrate iron reductase

Abstract

Publication types

MeSH terms

Substances

Grants and funding