title: A structural analysis of DNA binding by hSSB1 (NABP2/OBFC2B) in solution.
abstract: Single-stranded DNA binding proteins (SSBs) play an important role in DNA processing events such as replication, recombination and repair. Human single-stranded DNA binding protein 1 (hSSB1/NABP2/OBFC2B) contains a single oligosaccharide/oligonucleotide binding (OB) domain followed by a charged C-terminus and is structurally homologous to the SSB from the hyperthermophilic crenarchaeote Sulfolobus solfataricus Recent work has revealed that hSSB1 is critical to homologous recombination and numerous other important biological processes such as the regulation of telomeres, the maintenance of DNA replication forks and oxidative damage repair. Since the ability of hSSB1 to directly interact with single-stranded DNA (ssDNA) is paramount for all of these processes, understanding the molecular details of ssDNA recognition is essential. In this study, we have used solution-state nuclear magnetic resonance in combination with biophysical and functional experiments to structurally analyse ssDNA binding by hSSB1. We reveal that ssDNA recognition in solution is modulated by base-stacking of four key aromatic residues within the OB domain. This DNA binding mode differs significantly from the recently determined crystal structure of the SOSS1 complex containing hSSB1 and ssDNA. Our findings elucidate the detailed molecular mechanism in solution of ssDNA binding by hSSB1, a major player in the maintenance of genomic stability.
authors.affiliation: School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia.
authors.forename: Christine
authors.initials: C
authors.lastname: Touma
authors.affiliation: School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia.
authors.forename: Ruvini
authors.initials: R
authors.lastname: Kariawasam
authors.affiliation: School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia.
authors.forename: Adrian X
authors.initials: AX
authors.lastname: Gimenez
authors.affiliation: School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia.
authors.forename: Ray E
authors.initials: RE
authors.lastname: Bernardo
authors.affiliation: School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia.
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Ashton
authors.affiliation: School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia.
authors.forename: Mark N
authors.initials: MN
authors.lastname: Adams
authors.affiliation: School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Paquet
authors.affiliation: School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia.
authors.forename: Tristan I
authors.initials: TI
authors.lastname: Croll
authors.affiliation: School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: O'Byrne
authors.affiliation: School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Richard
authors.affiliation: School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia School of Molecular Biosciences, University of Sydney, NSW 2006, Australia l.cubeddu@westernsydney.edu.au.
authors.forename: Liza
authors.initials: L
authors.lastname: Cubeddu
authors.affiliation: School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia School of Molecular Biosciences, University of Sydney, NSW 2006, Australia r.gamsjaeger@westernsydney.edu.au.
authors.forename: Roland
authors.identifier: 0000-0003-1095-2569
authors.initials: R
authors.lastname: Gamsjaeger
mesh_terms: D000595:Amino Acid Sequence; D024322:Amino Acids, Aromatic / Q000378:metabolism; D004252:DNA Mutational Analysis; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D000072417:Protein Domains; D016415:Sequence Alignment; D012996:Solutions
chemical_list: D024322:Amino Acids, Aromatic; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D024101:Mitochondrial Proteins; C504091:NABP2 protein, human; D012996:Solutions