Thermotoga maritima NusG: domain interaction mediates autoinhibition and thermostability.
Nucleic Acids Res
; 45(1): 446-460, 2017 Jan 09.
Article
em En
| MEDLINE
| ID: mdl-27899597
ABSTRACT
NusG, the only universally conserved transcription factor, comprises an N- and a C-terminal domain (NTD, CTD) that are flexibly connected and move independently in Escherichia coli and other organisms. In NusG from the hyperthermophilic bacterium Thermotoga maritima (tmNusG), however, NTD and CTD interact tightly. This closed state stabilizes the CTD, but masks the binding sites for the interaction partners Rho, NusE and RNA polymerase (RNAP), suggesting that tmNusG is autoinhibited. Furthermore, tmNusG and some other bacterial NusGs have an additional domain, DII, of unknown function. Here we demonstrate that tmNusG is indeed autoinhibited and that binding to RNAP may stabilize the open conformation. We identified two interdomain salt bridges as well as Phe336 as major determinants of the domain interaction. By successive weakening of this interaction we show that after domain dissociation tmNusG-CTD can bind to Rho and NusE, similar to the Escherichia coli NusG-CTD, indicating that these interactions are conserved in bacteria. Furthermore, we show that tmNusG-DII interacts with RNAP as well as nucleic acids with a clear preference for double stranded DNA. We suggest that tmNusG-DII supports tmNusG recruitment to the transcription elongation complex and stabilizes the tmNusGRNAP complex, a necessary adaptation to high temperatures.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Fator Rho
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Fatores de Transcrição
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RNA Polimerases Dirigidas por DNA
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DNA Bacteriano
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Regulação Bacteriana da Expressão Gênica
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Fatores de Alongamento de Peptídeos
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Thermotoga maritima
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Proteínas de Escherichia coli
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Alemanha