Hyperosmotic Stress Allosterically Reconfigures Betaine Binding Pocket in BetP.
J Mol Biol
; 434(17): 167747, 2022 09 15.
Article
em En
| MEDLINE
| ID: mdl-35870651
ABSTRACT
The transporter BetP in C. glutamicum is essential in maintaining bacterial cell viability during hyperosmotic stress and functions by co-transporting betaine and Na+ into bacterial cells. Hyperosmotic stress leads to increased intracellular K+ concentrations which in turn promotes betaine binding. While structural details of multiple end state conformations of BetP have provided high resolution snapshots, how K+ sensing by the C-terminal domain is allosterically relayed to the betaine binding site is not well understood. In this study, we describe conformational dynamics in solution of BetP using amide hydrogen/deuterium exchange mass spectrometry. These reveal how K+ alters conformation of the disordered C- and N-terminal domains to allosterically reconfigure transmembrane helices 3, 8, and 10 to enhance betaine interactions. A map of the betaine binding site, at near single amino acid resolution, reveals a critical extrahelical H-bond mediated by TM3 with betaine.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pressão Osmótica
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Proteínas de Bactérias
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Betaína
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Corynebacterium glutamicum
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Proteínas da Membrana Plasmática de Transporte de GABA
Idioma:
En
Revista:
J Mol Biol
Ano de publicação:
2022
Tipo de documento:
Article