IraM remodels the RssB segmented helical linker to stabilize σs against degradation by ClpXP.
J Biol Chem
; 300(2): 105568, 2024 Feb.
Article
em En
| MEDLINE
| ID: mdl-38103640
ABSTRACT
Upon Mg2+ starvation, a condition often associated with virulence, enterobacteria inhibit the ClpXP-dependent proteolysis of the master transcriptional regulator, σs, via IraM, a poorly understood antiadaptor that prevents RssB-dependent loading of σs onto ClpXP. This inhibition results in σs accumulation and expression of stress resistance genes. Here, we report on the structural analysis of RssB bound to IraM, which reveals that IraM induces two folding transitions within RssB, amplified via a segmented helical linker. These conformational changes result in an open, yet inhibited RssB structure in which IraM associates with both the C-terminal and N-terminal domains of RssB and prevents binding of σs to the 4-5-5 face of the N-terminal receiver domain. This work highlights the remarkable structural plasticity of RssB and reveals how a stress-specific RssB antagonist modulates a core stress response pathway that could be leveraged to control biofilm formation, virulence, and the development of antibiotic resistance.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fatores de Transcrição
/
Modelos Moleculares
/
Proteínas de Escherichia coli
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Estados Unidos