Identification and properties of the crenarchaeal single-stranded DNA binding protein from Sulfolobus solfataricus.
Single-stranded DNA binding proteins (SSBs) play central roles in cellular and viral processes involving the generation of single-stranded DNA. These include DNA replication, homologous recombination and DNA repair pathways. SSBs bind DNA using four 'OB-fold' (oligonucleotide/oligosaccharide binding fold) domains that can be organised in a variety of overall quaternary structures. Thus eubacterial SSBs are homotetrameric whilst the eucaryal RPA protein is a heterotrimer and euryarchaeal proteins vary significantly in their subunit compositions. We demonstrate that the crenarchaeal SSB protein is an abundant protein with a unique structural organisation, existing as a monomer in solution and multimerising on DNA binding. The protein binds single-stranded DNA distributively with a binding site size of approximately 5 nt per monomer. Sulfolobus SSB lacks the zinc finger motif found in the eucaryal and euryarchaeal proteins, possessing instead a flexible C-terminal tail, sensitive to trypsin digestion, that is not required for DNA binding. In comparison with Escherichia coli SSB, the tail may play a role in protein-protein interactions during DNA replication and repair.
Wadsworth
R I
RI
Centre for Biomolecular Science, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK.
White
M F
MF
D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D003432:Cross-Linking Reagents / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics; D005453:Fluorescence; D005976:Glutaral / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D016944:Sulfolobus / Q000737:chemistry / Q000235:genetics*; D014357:Trypsin / Q000378:metabolism; D014364:Tryptophan / Q000378:metabolism
D019843:Archaeal Proteins; D003432:Cross-Linking Reagents; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D021122:Protein Subunits; D011994:Recombinant Proteins; D014364:Tryptophan; D014357:Trypsin; D005976:Glutaral