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The Two-Component System RsrS-RsrR Regulates the Tetrathionate Intermediate Pathway for Thiosulfate Oxidation in
Zhao-Bao Wang1, Ya-Qing Li1, Jian-Qun Lin1
1State Key Laboratory of Microbial Technology, Shandong University Jinan, China.
Frontiers in Microbiology
|November 19, 2016
Summary
The RsrS-RsrR system positively regulates the tetrathionate intermediate (S4I) pathway in Acidithiobacillus caldus, a key bioleaching bacterium. This regulation involves RsrR binding to a specific DNA sequence, impacting sulfur metabolism and bacterial growth.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Acidithiobacillus caldus (A. caldus) utilizes a complex inorganic sulfur compound metabolism network for bioleaching.
- Thiosulfate is a central intermediate metabolized via the tetrathionate intermediate (S4I) pathway, involving DoxDA and TetH enzymes.
- A two-component system, RsrS-RsrR, is present in A. caldus and co-localized with S4I pathway genes.
Purpose of the Study:
- To investigate the regulatory role of the RsrS-RsrR two-component system on the S4I pathway in A. caldus.
- To elucidate the mechanism of S4I pathway regulation by RsrS-RsrR.
- To develop and utilize genetic tools for studying A. caldus.
Main Methods:
- Construction of markerless gene knockout strains (ΔrsrR and ΔrsrS) in A. caldus.
- Transcriptional analysis of the tetH gene cluster in wild-type and mutant strains.
- Electrophoretic mobility shift assays (EMSAs) and promoter-probe vector studies to identify RsrR binding sites.
- Growth analysis of mutant strains in tetrathionate-containing medium.
Main Results:
- The RsrS-RsrR system positively regulates the S4I pathway in A. caldus.
- RsrR binds to a 19 bp inverted repeat sequence (AACACCTGTTACACCTGTT) upstream of the tetH promoter.
- ΔrsrR and ΔrsrS mutants showed significant growth differences compared to the wild type in K2S4O6-medium.
- Absence of rsrS or rsrR differentially affected gene expression related to sulfur metabolism and signaling.
Conclusions:
- The RsrS-RsrR system acts as a transcriptional activator for the tetH-doxDA operon, controlling the S4I pathway.
- A model for tetrathionate sensing by RsrS and signal transduction via RsrR is proposed.
- This study provides a new genetic tool for A. caldus research and deepens the understanding of sulfur metabolism in this bacterium.
Keywords:
Acidithiobacillus caldusRsrS-RsrRS4I pathwaycis regulatory elementsulfur metabolismthiosulfate oxidationtranscriptional regulationtwo-component systemMore Related Videos
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