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Recombinant Protein Expression, Crystallization, and Biophysical Studies of a Bacillus-conserved Nucleotide Pyrophosphorylase, BcMazG
Published on: May 16, 2017
Two small c-type cytochromes affect virulence gene expression in Bacillus anthracis
Adam C Wilson1, James A Hoch, Marta Perego
1The Scripps Research Institute, Department of Molecular and Experimental Medicine, Division of Cellular Biology, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Molecular Microbiology
|February 19, 2009
Summary
Researchers discovered two new proteins, CccA and CccB, that control anthrax toxin production in Bacillus anthracis by regulating the master virulence gene AtxA. This finding impacts understanding bacterial virulence and cytochrome c function.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Anthrax toxin gene expression in Bacillus anthracis is crucial for virulence.
- Toxin expression is influenced by environmental factors like temperature and bicarbonate.
- Identifying regulatory mechanisms is key to understanding B. anthracis pathogenesis.
Purpose of the Study:
- To identify novel factors regulating anthrax toxin gene expression.
- To elucidate the role of haem biosynthesis and cytochrome c maturation in virulence regulation.
- To characterize the function of previously unstudied proteins in B. anthracis.
Main Methods:
- Transposon mutagenesis was employed under non-inducing conditions to isolate mutants with altered toxin expression.
- Genetic analysis was performed to identify the mutated genes and pathways.
- The function of identified proteins (CccA, CccB, BAS3568) in virulence regulation was investigated.
Main Results:
- Mutations in haem biosynthetic and cytochrome c maturation pathways led to premature high-level toxin expression.
- Two haem-dependent c-type cytochromes, CccA and CccB, were identified as regulators of toxin gene expression.
- These cytochromes affect the master virulence regulator AtxA, with their loss leading to deregulated AtxA and toxin expression.
- A conserved protein, BAS3568, was implicated in cytochrome c activity and virulence regulation.
Conclusions:
- CccA and CccB are novel regulators of B. anthracis virulence, functioning through the AtxA pathway.
- This study reveals the first identified function for these small c-type cytochromes in Bacillus species.
- The findings have implications for understanding virulence in other pathogenic bacteria and cytochrome c function in Gram-positive bacteria.
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