Abstract
RfaH, member of the NusG/Spt5 family, activates virulence genes in Gram-negative pathogens. RfaH exists in two states, with its C-terminal domain (CTD) folded either as α-helical hairpin or β-barrel. In free RfaH, the α-helical CTD interacts with, and masks the RNA polymerase binding site on, the N-terminal domain, autoinhibiting RfaH and restricting its recruitment to opsDNA sequences. Upon activation, the domains separate and the CTD refolds into the β-barrel, which recruits a ribosome, activating translation. Using NMR spectroscopy, we show that only a complete ops-paused transcription elongation complex activates RfaH, probably via a transient encounter complex, allowing the refolded CTD to bind ribosomal protein S10. We also demonstrate that upon release from the elongation complex, the CTD transforms back into the autoinhibitory α-state, resetting the cycle. Transformation-coupled autoinhibition allows RfaH to achieve high specificity and potent activation of gene expression.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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DNA-Binding Proteins / metabolism
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DNA-Directed RNA Polymerases / metabolism*
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Escherichia coli / genetics*
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Escherichia coli / metabolism*
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism*
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Gene Expression Regulation, Bacterial
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Molecular Dynamics Simulation
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Peptide Elongation Factors / genetics
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Peptide Elongation Factors / metabolism*
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Protein Binding
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Protein Biosynthesis
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Protein Folding*
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Protein Interaction Domains and Motifs
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Protein Structure, Tertiary
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism*
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Ribosomal Proteins
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Ribosomes
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Trans-Activators / genetics
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Trans-Activators / metabolism*
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Transcription Factors / metabolism
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Transcription, Genetic
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Virulence / genetics
Substances
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Bacterial Proteins
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DNA-Binding Proteins
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Escherichia coli Proteins
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NusG protein, E coli
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Peptide Elongation Factors
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RNA-Binding Proteins
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RfaH protein, E coli
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Ribosomal Proteins
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Trans-Activators
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Transcription Factors
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antiterminator proteins, Bacteria
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ribosomal protein S10
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DNA-Directed RNA Polymerases