Abstract
Global changes in bacterial gene expression can be orchestrated by the coordinated activation/deactivation of alternative sigma (σ) factor subunits of RNA polymerase. Sigma factors themselves are regulated in myriad ways, including via anti-sigma factors. Here, we have determined the solution structure of anti-sigma factor CsfB, responsible for inhibition of two alternative sigma factors, σG and σE, during spore formation by Bacillus subtilis. CsfB assembles into a symmetrical homodimer, with each monomer bound to a single Zn2+ ion via a treble-clef zinc finger fold. Directed mutagenesis indicates that dimer formation is critical for CsfB-mediated inhibition of both σG and σE, and we have characterized these interactions in vitro. This work represents an advance in our understanding of how CsfB mediates inhibition of two alternative sigma factors to drive developmental gene expression in a bacterium.
Keywords:
Bacillus subtilis; CsfB; NMR; anti-sigma factor; sigma factor; sporulation; treble clef.
Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Bacillus subtilis / chemistry*
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Bacillus subtilis / genetics
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Bacillus subtilis / metabolism
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Binding Sites
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Cations, Divalent
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Cloning, Molecular
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Crystallography, X-Ray
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Escherichia coli / genetics
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Escherichia coli / metabolism
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Gene Expression Regulation, Bacterial*
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Genetic Vectors / chemistry
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Genetic Vectors / metabolism
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Models, Molecular
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Mutation
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Protein Binding
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Protein Conformation, alpha-Helical
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Protein Conformation, beta-Strand
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Protein Interaction Domains and Motifs
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Protein Isoforms / antagonists & inhibitors
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Protein Isoforms / chemistry
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Protein Isoforms / genetics
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Protein Isoforms / metabolism
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Protein Multimerization
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Repressor Proteins / chemistry*
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Repressor Proteins / genetics
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Repressor Proteins / metabolism
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Sequence Alignment
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Sequence Homology, Amino Acid
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Sigma Factor / antagonists & inhibitors
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Sigma Factor / chemistry*
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Sigma Factor / genetics
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Sigma Factor / metabolism
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Spores, Bacterial / chemistry*
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Spores, Bacterial / genetics
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Spores, Bacterial / metabolism
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Zinc / chemistry*
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Zinc / metabolism
Substances
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Cations, Divalent
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Protein Isoforms
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Recombinant Proteins
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Repressor Proteins
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Sigma Factor
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Zinc