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Mol Microbiol. 2017 Jun;104(5):837-850. doi: 10.1111/mmi.13667. Epub 2017 Apr 6.

The RicAFT (YmcA-YlbF-YaaT) complex carries two [4Fe-4S]2+ clusters and may respond to redox changes.

Author information

1
Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.
2
Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.
3
Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.
4
Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA.
5
Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.

Abstract

During times of environmental insult, Bacillus subtilis undergoes developmental changes leading to biofilm formation, sporulation and competence. Each of these states is regulated in part by the phosphorylated form of the master response regulator Spo0A (Spo0A∼P). The phosphorylation state of Spo0A is controlled by a multi-component phosphorelay. RicA, RicF and RicT (previously YmcA, YlbF and YaaT) have been shown to be important regulatory proteins for multiple developmental fates. These proteins directly interact and form a stable complex, which has been proposed to accelerate the phosphorelay. Indeed, this complex is sufficient to stimulate the rate of phosphotransfer amongst the phosphorelay proteins in vitro. In this study, we demonstrate that two [4Fe-4S]2+ clusters can be assembled on the complex. As with other iron-sulfur cluster-binding proteins, the complex was also found to bind FAD, hinting that these cofactors may be involved in sensing the cellular redox state. This work provides the first comprehensive characterization of an iron-sulfur protein complex that regulates Spo0A∼P levels. Phylogenetic and genetic evidence suggests that the complex plays a broader role beyond stimulation of the phosphorelay.

PMID:
28295778
PMCID:
PMC5444954
DOI:
10.1111/mmi.13667
[Indexed for MEDLINE]
Free PMC Article

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