Phase separation by ssDNA binding protein controlled via protein−protein and protein−DNA interactions
| Autor: | András Málnási-Csizmadia, Veronika Baráth, János Pálinkás, Zoltán Kovács, Rita Pancsa, Gábor M. Harami, Krisztián Tárnok, Mihály Kovács |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
DNA Repair
DNA repair DNA damage Liquid-Liquid Extraction DNA Single-Stranded Peptide medicine.disease_cause Genome Biochemistry Single-stranded binding protein stomatognathic system medicine Escherichia coli SSB chemistry.chemical_classification Multidisciplinary membraneless organelle biology Chemistry Protein protein Escherichia coli Proteins Biological Sciences eye diseases DNA-Binding Proteins stomatognathic diseases DNA Repair Enzymes phase transition biology.protein Biophysics Linker liquid−liquid phase separation DNA Damage Protein Binding |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | Significance Cells must rapidly and efficiently react to DNA damage to avoid its harmful consequences. Here we report a molecular mechanism that gives rise to a model of how bacterial cells mobilize DNA repair proteins for timely response to genomic stress and initiation of DNA repair upon exposure of single-stranded DNA. We found that bacterial single-stranded DNA binding protein (SSB), a central player in genome metabolism, can undergo dynamic phase separation under physiological conditions. SSB condensates can store a wide array of DNA repair proteins that specifically interact with SSB. However, elevated levels of single-stranded DNA during genomic stress can dissolve SSB condensates, enabling rapid mobilization of SSB and SSB-interacting proteins to sites of DNA damage. 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. |
| Databáze: | OpenAIRE |
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