Journal article
The Single-Stranded DNA Binding Protein of Sulfolobus solfataricus Acts in the Presynaptic Step of Homologous Recombination
Journal of molecular biology, Vol.397(1), pp.31-45
2010
Handle:
https://hdl.handle.net/2376/111041
PMID: 20080104
Abstract
Homologous recombination is an important pathway in the repair of DNA double-strand breaks in all organisms. In mesophiles, single-stranded DNA binding proteins (SSBs) are believed to be involved in the removal of single-stranded DNA (ssDNA) secondary structure during the presynaptic step of homologous recombination, facilitating the formation of a contiguous Rad51/RecA nucleoprotein filament. Here we report a role for the thermophilic archaeal
Sulfolobus solfataricus SSB (SsoSSB) in the presynaptic step of homologous recombination. We have identified multiple quaternary structural forms of this protein
in vivo and examined the activity of SsoSSB with the strand-exchange protein
S. solfataricus RadA (SsoRadA). Using gel-shift analysis, we found that the two major forms of SsoSSB have different DNA binding affinities and site sizes. Biochemical examination of the monomeric form of SsoSSB suggests that it has a minor role in presynapsis and may slightly inhibit the ssDNA-dependent ATPase activity of SsoRadA. The tetrameric form of SsoSSB, however, significantly inhibits SsoRadA ssDNA-dependent ATPase activity under both saturating and subsaturating conditions. Order-of-addition experiments indicate that preincubation of tetrameric SsoSSB and SsoRadA prior to reaction initiation with ssDNA relieves the inhibition observed when SsoSSB is added either before or after SsoRadA. In addition, we demonstrate a direct interaction between SsoRadA and SsoSSB using coimmunoprecipitation. Taken together, these results suggest that a direct interaction between SsoSSB and SsoRadA may occur
in vivo prior to the formation of the SsoRadA nucleoprotein filament.
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Details
- Title
- The Single-Stranded DNA Binding Protein of Sulfolobus solfataricus Acts in the Presynaptic Step of Homologous Recombination
- Creators
- Michael L RolfsmeierCynthia A Haseltine
- Publication Details
- Journal of molecular biology, Vol.397(1), pp.31-45
- Academic Unit
- Molecular Biosciences, School of
- Publisher
- Elsevier Ltd
- Identifiers
- 99900547476201842
- Language
- English
- Resource Type
- Journal article