RRC ID 66256
Author Silva LSO, Baptista JM, Batley C, Andrews SC, Saraiva LM.
Title The Di-iron RIC Protein (YtfE) of Escherichia coli Interacts with the DNA-Binding Protein from Starved Cells (Dps) To Diminish RIC Protein-Mediated Redox Stress.
Journal J Bacteriol
Abstract The RIC (repair of iron clusters) protein of Escherichia coli is a di-iron hemerythrin-like protein that has a proposed function in repairing stress-damaged iron-sulfur clusters. In this work, we performed a bacterial two-hybrid screening to search for RIC-protein interaction partners in E. coli As a result, the DNA-binding protein from starved cells (Dps) was identified, and its potential interaction with RIC was tested by bacterial adenylate cyclase-based two-hybrid (BACTH) system, bimolecular fluorescence complementation, and pulldown assays. Using the activity of two Fe-S-containing enzymes as indicators of cellular Fe-S cluster damage, we observed that strains with single deletions of ric or dps have significantly lower aconitase and fumarase activities. In contrast, the ric dps double mutant strain displayed no loss of aconitase and fumarase activity with respect to that of the wild type. Additionally, while complementation of the ric dps double mutant with ric led to a severe loss of aconitase activity, this effect was no longer observed when a gene encoding a di-iron site variant of the RIC protein was employed. The dps mutant exhibited a large increase in reactive oxygen species (ROS) levels, but this increase was eliminated when ric was also inactivated. Absence of other iron storage proteins, or of peroxidase and catalases, had no impact on RIC-mediated redox stress induction. Hence, we show that RIC interacts with Dps in a manner that serves to protect E. coli from RIC protein-induced ROS.IMPORTANCE The mammalian immune system produces reactive oxygen and nitrogen species that kill bacterial pathogens by damaging key cellular components, such as lipids, DNA, and proteins. However, bacteria possess detoxifying and repair systems that mitigate these deleterious effects. The Escherichia coli RIC (repair of iron clusters) protein is a di-iron hemerythrin-like protein that repairs stress-damaged iron-sulfur clusters. E. coli Dps is an iron storage protein of the ferritin superfamily with DNA-binding capacity that protects cells from oxidative stress. This work shows that the E. coli RIC and Dps proteins interact in a fashion that counters RIC protein-induced reactive oxygen species (ROS). Altogether, we provide evidence for the formation of a new bacterial protein complex and reveal a novel contribution for Dps in bacterial redox stress protection.
Volume 200(24)
Published 2018-12-15
DOI 10.1128/JB.00527-18
PII JB.00527-18
PMID 30249704
PMC PMC6256020
MeSH Aconitate Hydratase / metabolism Bacterial Outer Membrane Proteins / genetics* Bacterial Outer Membrane Proteins / metabolism Escherichia coli / genetics Escherichia coli / growth & development* Escherichia coli / metabolism Escherichia coli Proteins / genetics* Escherichia coli Proteins / metabolism Fumarate Hydratase / metabolism Gene Expression Regulation, Bacterial Mutation Oxidation-Reduction Reactive Oxygen Species / metabolism* Two-Hybrid System Techniques
IF 3.234
Prokaryotes E. coli