title: The iron stimulon and fur regulon of Geobacter sulfurreducens and their role in energy metabolism.
abstract: Iron plays a critical role in the physiology of Geobacter species. It serves as both an essential component for proteins and cofactors and an electron acceptor during anaerobic respiration. Here, we investigated the iron stimulon and ferric uptake regulator (Fur) regulon of Geobacter sulfurreducens to examine the coordination between uptake of Fe(II) and the reduction of Fe(III) at the transcriptional level. Gene expression studies across a variety of different iron concentrations in both the wild type and a Δfur mutant strain were used to determine the iron stimulon. The stimulon consists of a broad range of gene products, ranging from iron-utilizing to central metabolism and iron reduction proteins. Integration of gene expression and chromatin immunoprecipitation (ChIP) data sets assisted in the identification of the Fur transcriptional regulatory network and Fur's role as a regulator of the iron stimulon. Additional physiological and transcriptional analyses of G. sulfurreducens grown with various Fe(II) concentrations revealed the depth of Fur's involvement in energy metabolism and the existence of redundancy within the iron-regulatory network represented by IdeR, an alternative iron transcriptional regulator. These characteristics enable G. sulfurreducens to thrive in environments with fluctuating iron concentrations by providing it with a robust mechanism to maintain tight and deliberate control over intracellular iron homeostasis.
authors.affiliation: Department of Bioengineering, University of California, San Diego, La Jolla, California, USA.
authors.forename: Mallory
authors.initials: M
authors.lastname: Embree
authors.forename: Yu
authors.initials: Y
authors.lastname: Qiu
authors.forename: Wendy
authors.initials: W
authors.lastname: Shieu
authors.forename: Harish
authors.initials: H
authors.lastname: Nagarajan
authors.forename: Regina
authors.initials: R
authors.lastname: O'Neil
authors.forename: Derek
authors.initials: D
authors.lastname: Lovley
authors.forename: Karsten
authors.initials: K
authors.lastname: Zengler
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004734:Energy Metabolism; D015964:Gene Expression Regulation, Bacterial; D045302:Geobacter / Q000235:genetics* / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D018085:Regulon
chemical_list: D001426:Bacterial Proteins; D007501:Iron