1
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Harami GM, Pálinkás J, Kovács ZJ, Jezsó B, Tárnok K, Harami-Papp H, Hegedüs J, Mahmudova L, Kucsma N, Tóth S, Szakács G, Kovács M. Redox-dependent condensation and cytoplasmic granulation by human ssDNA-binding protein-1 delineate roles in oxidative stress response. iScience 2024; 27:110788. [PMID: 39286502 PMCID: PMC11403420 DOI: 10.1016/j.isci.2024.110788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 06/06/2024] [Accepted: 08/19/2024] [Indexed: 09/19/2024] Open
Abstract
Human single-stranded DNA binding protein 1 (hSSB1/NABP2/OBFC2B) plays central roles in DNA repair. Here, we show that purified hSSB1 undergoes redox-dependent liquid-liquid phase separation (LLPS) in the presence of single-stranded DNA or RNA, features that are distinct from those of LLPS by bacterial SSB. hSSB1 nucleoprotein droplets form under physiological ionic conditions in response to treatment modeling cellular oxidative stress. hSSB1's intrinsically disordered region is indispensable for LLPS, whereas all three cysteine residues of the oligonucleotide/oligosaccharide-binding fold are necessary to maintain redox-sensitive droplet formation. Proteins interacting with hSSB1 show selective enrichment inside hSSB1 droplets, suggesting tight content control and recruitment functions for the condensates. While these features appear instrumental for genome repair, we detected cytoplasmic hSSB1 condensates in various cell lines colocalizing with stress granules upon oxidative stress, implying extranuclear function in cellular stress response. Our results suggest condensation-linked roles for hSSB1, linking genome repair and cytoplasmic defense.
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Affiliation(s)
- Gábor M Harami
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
| | - János Pálinkás
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
| | - Zoltán J Kovács
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
- HUN-REN-ELTE Motor Pharmacology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
| | - Bálint Jezsó
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
| | - Krisztián Tárnok
- Department of Physiology and Neurobiology, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
| | - Hajnalka Harami-Papp
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
| | - József Hegedüs
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
| | - Lamiya Mahmudova
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
| | - Nóra Kucsma
- HUN-REN Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, 1117 Budapest, Hungary
| | - Szilárd Tóth
- HUN-REN Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, 1117 Budapest, Hungary
| | - Gergely Szakács
- HUN-REN Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, 1117 Budapest, Hungary
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Wien, Austria
| | - Mihály Kovács
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
- HUN-REN-ELTE Motor Pharmacology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, 1117 Budapest, Hungary
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2
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Schuurs ZP, Martyn AP, Soltau CP, Beard S, Shah ET, Adams MN, Croft LV, O’Byrne KJ, Richard DJ, Gandhi NS. An Exploration of Small Molecules That Bind Human Single-Stranded DNA Binding Protein 1. BIOLOGY 2023; 12:1405. [PMID: 37998004 PMCID: PMC10669474 DOI: 10.3390/biology12111405] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/24/2023] [Accepted: 10/30/2023] [Indexed: 11/25/2023]
Abstract
Human single-stranded DNA binding protein 1 (hSSB1) is critical to preserving genome stability, interacting with single-stranded DNA (ssDNA) through an oligonucleotide/oligosaccharide binding-fold. The depletion of hSSB1 in cell-line models leads to aberrant DNA repair and increased sensitivity to irradiation. hSSB1 is over-expressed in several types of cancers, suggesting that hSSB1 could be a novel therapeutic target in malignant disease. hSSB1 binding studies have focused on DNA; however, despite the availability of 3D structures, small molecules targeting hSSB1 have not been explored. Quinoline derivatives targeting hSSB1 were designed through a virtual fragment-based screening process, synthesizing them using AlphaLISA and EMSA to determine their affinity for hSSB1. In parallel, we further screened a structurally diverse compound library against hSSB1 using the same biochemical assays. Three compounds with nanomolar affinity for hSSB1 were identified, exhibiting cytotoxicity in an osteosarcoma cell line. To our knowledge, this is the first study to identify small molecules that modulate hSSB1 activity. Molecular dynamics simulations indicated that three of the compounds that were tested bound to the ssDNA-binding site of hSSB1, providing a framework for the further elucidation of inhibition mechanisms. These data suggest that small molecules can disrupt the interaction between hSSB1 and ssDNA, and may also affect the ability of cells to repair DNA damage. This test study of small molecules holds the potential to provide insights into fundamental biochemical questions regarding the OB-fold.
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Affiliation(s)
- Zachariah P. Schuurs
- Centre for Genomics and Personalised Health, School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; (Z.P.S.); (A.P.M.)
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
| | - Alexander P. Martyn
- Centre for Genomics and Personalised Health, School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; (Z.P.S.); (A.P.M.)
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
| | - Carl P. Soltau
- School of Chemistry and Physics, Centre for Materials Science, Queensland University of Technology, Brisbane, QLD 4000, Australia;
| | - Sam Beard
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
| | - Esha T. Shah
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Translational Research Institute, Woolloongabba, QLD 4102, Australia
| | - Mark N. Adams
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Translational Research Institute, Woolloongabba, QLD 4102, Australia
| | - Laura V. Croft
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Translational Research Institute, Woolloongabba, QLD 4102, Australia
| | - Kenneth J. O’Byrne
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
- Cancer Services, Princess Alexandra Hospital—Metro South Health, Woolloongabba, QLD 4102, Australia
| | - Derek J. Richard
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Translational Research Institute, Woolloongabba, QLD 4102, Australia
| | - Neha S. Gandhi
- Centre for Genomics and Personalised Health, School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; (Z.P.S.); (A.P.M.)
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Queensland University of Technology (QUT), Translational Research Institute (TRI), Woolloongabba, QLD 4102, Australia; (S.B.); (M.N.A.); (L.V.C.); (K.J.O.); (D.J.R.)
- Department of Computer Science and Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, India
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3
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El‐Kamand S, Adams MN, Matthews JM, Du Plessis M, Crossett B, Connolly A, Breen N, Dudley A, Richard DJ, Gamsjaeger R, Cubeddu L. The molecular details of a novel phosphorylation-dependent interaction between MRN and the SOSS complex. Protein Sci 2023; 32:e4782. [PMID: 37705456 PMCID: PMC10521234 DOI: 10.1002/pro.4782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/08/2023] [Accepted: 09/11/2023] [Indexed: 09/15/2023]
Abstract
The repair of double-strand DNA breaks (DSBs) by homologous recombination is crucial in the maintenance of genome integrity. While the key role of the Mre11-Rad50-Nbs1 (MRN) complex in repair is well known, hSSB1 (SOSSB and OBFC2B), one of the main components of the sensor of single-stranded DNA (SOSS) protein complex, has also been shown to rapidly localize to DSB breaks and promote repair. We have previously demonstrated that hSSB1 binds directly to Nbs1, a component of the MRN complex, in a DNA damage-independent manner. However, recruitment of the MRN complex has also been demonstrated by an interaction between Integrator Complex Subunit 3 (INTS3; also known as SOSSA), another member of the SOSS complex, and Nbs1. In this study, we utilize a combined approach of in silico, biochemical, and functional experiments to uncover the molecular details of INTS3 binding to Nbs1. We demonstrate that the forkhead-associated domain of Nbs1 interacts with INTS3 via phosphorylation-dependent binding to INTS3 at Threonine 592, with contributions from Serine 590. Based on these data, we propose a model of MRN recruitment to a DSB via INTS3.
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Affiliation(s)
- Serene El‐Kamand
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Mark N. Adams
- Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthTranslational Research Institute, Queensland University of TechnologyBrisbaneQueenslandAustralia
| | - Jacqueline M. Matthews
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
| | | | - Ben Crossett
- Sydney Mass SpectrometryUniversity of SydneySydneyNew South WalesAustralia
| | - Angela Connolly
- Sydney Mass SpectrometryUniversity of SydneySydneyNew South WalesAustralia
| | - Natasha Breen
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Alexander Dudley
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Derek J. Richard
- Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthTranslational Research Institute, Queensland University of TechnologyBrisbaneQueenslandAustralia
| | - Roland Gamsjaeger
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
| | - Liza Cubeddu
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
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4
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Jia Y, Cheng Z, Bharath SR, Sun Q, Su N, Huang J, Song H. Crystal structure of the INTS3/INTS6 complex reveals the functional importance of INTS3 dimerization in DSB repair. Cell Discov 2021; 7:66. [PMID: 34400606 PMCID: PMC8368002 DOI: 10.1038/s41421-021-00283-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 05/17/2021] [Indexed: 11/23/2022] Open
Abstract
SOSS1 is a single-stranded DNA (ssDNA)-binding protein complex that plays a critical role in double-strand DNA break (DSB) repair. SOSS1 consists of three subunits: INTS3, SOSSC, and hSSB1, with INTS3 serving as a scaffold to stabilize this complex. Moreover, the integrator complex subunit 6 (INTS6) participates in the DNA damage response through direct binding to INTS3, but how INTS3 interacts with INTS6, thereby impacting DSB repair, is not clear. Here, we determined the crystal structure of the C-terminus of INTS3 (INTS3c) in complex with the C-terminus of INTS6 (INTS6c) at a resolution of 2.4 Å. Structural analysis revealed that two INTS3c subunits dimerize and interact with INTS6c via conserved residues. Subsequent biochemical analyses confirmed that INTS3c forms a stable dimer and INTS3 dimerization is important for recognizing the longer ssDNA. Perturbation of INTS3c dimerization and disruption of the INTS3c/INTS6c interaction impair the DSB repair process. Altogether, these results unravel the underappreciated role of INTS3 dimerization and the molecular basis of INTS3/INTS6 interaction in DSB repair.
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Affiliation(s)
- Yu Jia
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zixiu Cheng
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Sakshibeedu R Bharath
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore City, Singapore
| | - Qiangzu Sun
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Nannan Su
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jun Huang
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Haiwei Song
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China. .,Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore City, Singapore. .,Department of Biochemistry, National University of Singapore, 14 Science Drive, Singapore City, Singapore.
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5
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El-Kamand S, Du Plessis MD, Breen N, Johnson L, Beard S, Kwan AH, Richard DJ, Cubeddu L, Gamsjaeger R. A distinct ssDNA/RNA binding interface in the Nsp9 protein from SARS-CoV-2. Proteins 2021; 90:176-185. [PMID: 34369011 PMCID: PMC8441931 DOI: 10.1002/prot.26205] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 12/17/2022]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is a novel, highly infectious RNA virus that belongs to the coronavirus family. Replication of the viral genome is a fundamental step in the virus life cycle and SARS‐CoV‐2 non‐structural protein 9 (Nsp9) is shown to be essential for virus replication through its ability to bind RNA in the closely related SARS‐CoV‐1 strain. Two recent studies revealing the three‐dimensional structure of Nsp9 from SARS‐CoV‐2 have demonstrated a high degree of similarity between Nsp9 proteins within the coronavirus family. However, the binding affinity to RNA is very low which, until now, has prevented the determination of the structural details of this interaction. In this study, we have utilized nuclear magnetic resonance spectroscopy (NMR) in combination with surface biolayer interferometry (BLI) to reveal a distinct binding interface for both ssDNA and RNA that is different to the one proposed in the recently solved SARS‐CoV‐2 replication and transcription complex (RTC) structure. Based on these data, we have proposed a structural model of a Nsp9‐RNA complex, shedding light on the molecular details of these important interactions.
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Affiliation(s)
- Serene El-Kamand
- School of Science, Western Sydney University, Penrith, New South Wales, Australia
| | - Mar-Dean Du Plessis
- School of Science, Western Sydney University, Penrith, New South Wales, Australia
| | - Natasha Breen
- School of Science, Western Sydney University, Penrith, New South Wales, Australia
| | - Lexie Johnson
- School of Science, Western Sydney University, Penrith, New South Wales, Australia
| | - Samuel Beard
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, Australia
| | - Ann H Kwan
- School of Life and Environmental Sciences and Sydney Nano Institute, University of Sydney, New South Wales, Australia
| | - Derek J Richard
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, Australia
| | - Liza Cubeddu
- School of Science, Western Sydney University, Penrith, New South Wales, Australia.,School of Life and Environmental Sciences and Sydney Nano Institute, University of Sydney, New South Wales, Australia
| | - Roland Gamsjaeger
- School of Science, Western Sydney University, Penrith, New South Wales, Australia.,School of Life and Environmental Sciences and Sydney Nano Institute, University of Sydney, New South Wales, Australia
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6
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El-Kamand S, Du Plessis MD, Lawson T, Cubeddu L, Gamsjaeger R. Expression, Purification, and Solution-State NMR Analysis of the Two Human Single-Stranded DNA-Binding Proteins hSSB1 (NABP2/OBFC2B) and hSSB2 (NAPB1/OBFC2A). Methods Mol Biol 2021; 2281:229-240. [PMID: 33847962 DOI: 10.1007/978-1-0716-1290-3_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Single-stranded DNA-binding proteins (SSBs) are essential to all living organisms as protectors and guardians of the genome. Apart from the well-characterized RPA, humans have also evolved two further SSBs, termed hSSB1 and hSSB2. Over the last few years, we have used NMR spectroscopy to determine the molecular and structural details of both hSSBs and their interactions with DNA and RNA. Here we provide a detailed overview of how to express and purify recombinant versions of these important human proteins for the purpose of detailed structural analysis by high-resolution solution-state NMR.
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Affiliation(s)
- Serene El-Kamand
- School of Science, Western Sydney University, Penrith, NSW, Australia
| | | | - Teegan Lawson
- School of Science, Western Sydney University, Penrith, NSW, Australia
| | - Liza Cubeddu
- School of Science, Western Sydney University, Penrith, NSW, Australia.
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia.
| | - Roland Gamsjaeger
- School of Science, Western Sydney University, Penrith, NSW, Australia.
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia.
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7
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Oliveira MT, Ciesielski GL. The Essential, Ubiquitous Single-Stranded DNA-Binding Proteins. Methods Mol Biol 2021; 2281:1-21. [PMID: 33847949 DOI: 10.1007/978-1-0716-1290-3_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Maintenance of genomes is fundamental for all living organisms. The diverse processes related to genome maintenance entail the management of various intermediate structures, which may be deleterious if unresolved. The most frequent intermediate structures that result from the melting of the DNA duplex are single-stranded (ss) DNA stretches. These are thermodynamically less stable and can spontaneously fold into secondary structures, which may obstruct a variety of genome processes. In addition, ssDNA is more prone to breaking, which may lead to the formation of deletions or DNA degradation. Single-stranded DNA-binding proteins (SSBs) bind and stabilize ssDNA, preventing the abovementioned deleterious consequences and recruiting the appropriate machinery to resolve that intermediate molecule. They are present in all forms of life and are essential for their viability, with very few exceptions. Here we present an introductory chapter to a volume of the Methods in Molecular Biology dedicated to SSBs, in which we provide a general description of SSBs from various taxa.
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Affiliation(s)
- Marcos T Oliveira
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista "Júlio de Mesquita Filho", Jaboticabal, SP, Brazil
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8
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Lawson T, El-Kamand S, Boucher D, Duong DC, Kariawasam R, Bonvin AMJJ, Richard DJ, Gamsjaeger R, Cubeddu L. The structural details of the interaction of single-stranded DNA binding protein hSSB2 (NABP1/OBFC2A) with UV-damaged DNA. Proteins 2019; 88:319-326. [PMID: 31443132 DOI: 10.1002/prot.25806] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/02/2019] [Accepted: 08/19/2019] [Indexed: 12/17/2022]
Abstract
Single-stranded DNA-binding proteins (SSBs) are required for all known DNA metabolic events such as DNA replication, recombination and repair. While a wealth of structural and functional data is available on the essential human SSB, hSSB1 (NABP2/OBFC2B), the close homolog hSSB2 (NABP1/OBFC2A) remains relatively uncharacterized. Both SSBs possess a well-structured OB (oligonucleotide/oligosaccharide-binding) domain that is able to recognize single-stranded DNA (ssDNA) followed by a flexible carboxyl-tail implicated in the interaction with other proteins. Despite the high sequence similarity of the OB domain, several recent studies have revealed distinct functional differences between hSSB1 and hSSB2. In this study, we show that hSSB2 is able to recognize cyclobutane pyrimidine dimers (CPD) that form in cellular DNA as a consequence of UV damage. Using a combination of biolayer interferometry and NMR, we determine the molecular details of the binding of the OB domain of hSSB2 to CPD-containing ssDNA, confirming the role of four key aromatic residues in hSSB2 (W59, Y78, W82, and Y89) that are also conserved in hSSB1. Our structural data thus demonstrate that ssDNA recognition by the OB fold of hSSB2 is highly similar to hSSB1, indicating that one SSB may be able to replace the other in any initial ssDNA binding event. However, any subsequent recruitment of other repair proteins most likely depends on the divergent carboxyl-tail and as such is likely to be different between hSSB1 and hSSB2.
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Affiliation(s)
- Teegan Lawson
- School of Science and Health, Western Sydney University, Penrith, New South Wales, Australia
| | - Serene El-Kamand
- School of Science and Health, Western Sydney University, Penrith, New South Wales, Australia
| | - Didier Boucher
- Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, Australia
| | - Duc Cong Duong
- School of Science and Health, Western Sydney University, Penrith, New South Wales, Australia
| | - Ruvini Kariawasam
- School of Science and Health, Western Sydney University, Penrith, New South Wales, Australia
| | - Alexandre M J J Bonvin
- Bijvoet Center for Biomolecular Research, Faculty of Science - Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Derek J Richard
- Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, Australia
| | - Roland Gamsjaeger
- School of Science and Health, Western Sydney University, Penrith, New South Wales, Australia.,School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Liza Cubeddu
- School of Science and Health, Western Sydney University, Penrith, New South Wales, Australia.,School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
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9
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Lawson T, El-Kamand S, Kariawasam R, Richard DJ, Cubeddu L, Gamsjaeger R. A Structural Perspective on the Regulation of Human Single-Stranded DNA Binding Protein 1 (hSSB1, OBFC2B) Function in DNA Repair. Comput Struct Biotechnol J 2019; 17:441-446. [PMID: 30996823 PMCID: PMC6451162 DOI: 10.1016/j.csbj.2019.03.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 12/11/2022] Open
Abstract
Single-stranded DNA binding (SSB) proteins are essential to protect singe-stranded DNA (ssDNA) that exists as a result of several important DNA repair pathways in living cells. In humans, besides the well-characterised Replication Protein A (RPA) we have described another SSB termed human SSB1 (hSSB1, OBFC2B) and have shown that this protein is an important player in the maintenance of the genome. In this review we define the structural and biophysical details of how hSSB1 interacts with both DNA and other essential proteins. While the presence of the oligonucleotide/oligosaccharide (OB) domain ensures ssDNA binding by hSSB1, it has also been shown to self-oligomerise as well as interact with and being modified by several proteins highlighting the versatility that hSSB1 displays in the context of DNA repair. A detailed structural understanding of these processes will likely lead to the designs of tailored hSSB1 inhibitors as anti-cancer drugs in the near future.
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Affiliation(s)
- Teegan Lawson
- School of Science and Health, Western Sydney University, Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Serene El-Kamand
- School of Science and Health, Western Sydney University, Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Ruvini Kariawasam
- School of Science and Health, Western Sydney University, Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Derek J Richard
- Genome Stability Laboratory, Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
| | - Liza Cubeddu
- School of Science and Health, Western Sydney University, Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia.,School of Life and Environmental Sciences, University of Sydney, NSW 2006, Australia
| | - Roland Gamsjaeger
- School of Science and Health, Western Sydney University, Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia.,School of Life and Environmental Sciences, University of Sydney, NSW 2006, Australia
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Croft LV, Bolderson E, Adams MN, El-Kamand S, Kariawasam R, Cubeddu L, Gamsjaeger R, Richard DJ. Human single-stranded DNA binding protein 1 (hSSB1, OBFC2B), a critical component of the DNA damage response. Semin Cell Dev Biol 2019; 86:121-128. [DOI: 10.1016/j.semcdb.2018.03.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 12/18/2022]
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Kariawasam R, Knight M, Gamsjaeger R, Cubeddu L. Backbone 1H, 13C and 15N resonance assignments of the OB domain of the single stranded DNA-binding protein hSSB2 (NABP1/OBFC2A) and chemical shift mapping of the DNA-binding interface. BIOMOLECULAR NMR ASSIGNMENTS 2018; 12:107-111. [PMID: 29063999 DOI: 10.1007/s12104-017-9789-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/20/2017] [Indexed: 06/07/2023]
Abstract
Single stranded DNA-binding proteins (SSBs) are essential for the maintenance of genome integrity and are required in in all known cellular organisms. Over the last 10 years, the role of two new human SSBs, hSSB1 (NABP2/OBFC2B) and hSSB2 (NABP1/OBFC2A), has been described and characterised in various important DNA repair processes. Both these proteins are made up of a conserved oligonucleotide-binding (OB) fold that is responsible for ssDNA recognition as well a unique flexible carboxy-terminal extension involved in protein-protein interactions. Due to their similar domain organisation, hSSB1 and hSSB2 have been found to display some overlapping functions. However, several studies have also revealed cell- and tissue-specific roles for these two proteins, most likely due to small but significant differences in the protein sequence of the OB domains. While the molecular details of ssDNA binding by hSSB1 has been studied extensively, comparatively little is known about hSSB2. In this study, we use NMR solution-state backbone resonance assignments of the OB domain of hSSB2 to map the ssDNA interaction interface. Our data reveal that ssDNA binding by hSSB2 is driven by four key aromatic residues in analogy to hSSB1, however, some significant differences in the chemical shift perturbations are observed, reflecting differences in ssDNA recognition. Future studies will aim at determining the structural basis of these differences and thus help to gain a more comprehensive understanding of the functional divergences that these novel hSSBs display in the context of genome maintenance.
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Affiliation(s)
- Ruvini Kariawasam
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Maddison Knight
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Roland Gamsjaeger
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia.
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia.
| | - Liza Cubeddu
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia.
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia.
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Antony E, Lohman TM. Dynamics of E. coli single stranded DNA binding (SSB) protein-DNA complexes. Semin Cell Dev Biol 2018; 86:102-111. [PMID: 29588158 DOI: 10.1016/j.semcdb.2018.03.017] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 01/25/2023]
Abstract
Single stranded DNA binding proteins (SSB) are essential to the cell as they stabilize transiently open single stranded DNA (ssDNA) intermediates, recruit appropriate DNA metabolism proteins, and coordinate fundamental processes such as replication, repair and recombination. Escherichia coli single stranded DNA binding protein (EcSSB) has long served as the prototype for the study of SSB function. The structure, functions, and DNA binding properties of EcSSB are well established: The protein is a stable homotetramer with each subunit possessing an N-terminal DNA binding core, a C-terminal protein-protein interaction tail, and an intervening intrinsically disordered linker (IDL). EcSSB wraps ssDNA in multiple DNA binding modes and can diffuse along DNA to remove secondary structures and remodel other protein-DNA complexes. This review provides an update on these features based on recent findings, with special emphasis on the functional and mechanistic relevance of the IDL and DNA binding modes.
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Affiliation(s)
- Edwin Antony
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA.
| | - Timothy M Lohman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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