Phase separation by ssDNA binding protein controlled via protein-protein and protein-DNA interactions.
Proc Natl Acad Sci U S A
; 117(42): 26206-26217, 2020 10 20.
Article
em En
| MEDLINE
| ID: mdl-33020264
ABSTRACT
Bacterial single-stranded (ss)DNA-binding proteins (SSB) are essential for the replication and maintenance of the genome. SSBs share a conserved ssDNA-binding domain, a less conserved intrinsically disordered linker (IDL), and a highly conserved C-terminal peptide (CTP) motif that mediates a wide array of protein-protein interactions with DNA-metabolizing proteins. Here we show that the Escherichia coli SSB protein forms liquid-liquid phase-separated condensates in cellular-like conditions through multifaceted interactions involving all structural regions of the protein. SSB, ssDNA, and SSB-interacting molecules are highly concentrated within the condensates, whereas phase separation is overall regulated by the stoichiometry of SSB and ssDNA. Together with recent results on subcellular SSB localization patterns, our results point to a conserved mechanism by which bacterial cells store a pool of SSB and SSB-interacting proteins. Dynamic phase separation enables rapid mobilization of this protein pool to protect exposed ssDNA and repair genomic loci affected by DNA damage.
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MEDLINE
Assunto principal:
DNA de Cadeia Simples
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Proteínas de Escherichia coli
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Enzimas Reparadoras do DNA
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Proteínas de Ligação a DNA
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Escherichia coli
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Extração Líquido-Líquido
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article