TY - JOUR
T1 - The process of displacing the single-stranded DNA-binding protein from single-stranded DNA by RecO and RecR proteins
AU - Inoue, Jin
AU - Honda, Masayoshi
AU - Ikawa, Shukuko
AU - Shibata, Takehiko
AU - Mikawa, Tsutomu
N1 - Funding Information:
We thank Professor Seiki Kuramitsu for providing the expression plasmids of the T. thermophilus RecF pathway proteins used in this study. This work was supported in part by the Grants-in-Aid from the Japan Society for the Promotion of Science (JSPS) to T.S. and T.M. Funding to pay the Open Access publication charges for this article was also provided by JSPS.
PY - 2008/1
Y1 - 2008/1
N2 - The regions of single-stranded (ss) DNA that result from DNA damage are immediately coated by the ssDNA-binding protein (SSB). RecF pathway proteins facilitate the displacement of SSB from ssDNA, allowing the RecA protein to form protein filaments on the ssDNA region, which facilitates the process of recombinational DNA repair. In this study, we examined the mechanism of SSB displacement from ssDNA using purified Thermus thermophilus RecF pathway proteins. To date, RecO and RecR are thought to act as the RecOR complex. However, our results indicate that RecO and RecR have distinct functions. We found that RecR binds both RecF and RecO, and that RecO binds RecR, SSB and ssDNA. The electron microscopic studies indicated that SSB is displaced from ssDNA by RecO. In addition, pull-down assays indicated that the displaced SSB still remains indirectly attached to ssDNA through its interaction with RecO in the RecO-ssDNA complex. In the presence of both SSB and RecO, the ssDNA-dependent ATPase activity of RecA was inhibited, but was restored by the addition of RecR. Interestingly, the interaction of RecR with RecO affected the ssDNA-binding properties of RecO. These results suggest a model of SSB displacement from the ssDNA by RecF pathway proteins.
AB - The regions of single-stranded (ss) DNA that result from DNA damage are immediately coated by the ssDNA-binding protein (SSB). RecF pathway proteins facilitate the displacement of SSB from ssDNA, allowing the RecA protein to form protein filaments on the ssDNA region, which facilitates the process of recombinational DNA repair. In this study, we examined the mechanism of SSB displacement from ssDNA using purified Thermus thermophilus RecF pathway proteins. To date, RecO and RecR are thought to act as the RecOR complex. However, our results indicate that RecO and RecR have distinct functions. We found that RecR binds both RecF and RecO, and that RecO binds RecR, SSB and ssDNA. The electron microscopic studies indicated that SSB is displaced from ssDNA by RecO. In addition, pull-down assays indicated that the displaced SSB still remains indirectly attached to ssDNA through its interaction with RecO in the RecO-ssDNA complex. In the presence of both SSB and RecO, the ssDNA-dependent ATPase activity of RecA was inhibited, but was restored by the addition of RecR. Interestingly, the interaction of RecR with RecO affected the ssDNA-binding properties of RecO. These results suggest a model of SSB displacement from the ssDNA by RecF pathway proteins.
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U2 - 10.1093/nar/gkm1004
DO - 10.1093/nar/gkm1004
M3 - Article
C2 - 18000001
AN - SCOPUS:38349102456
SN - 0305-1048
VL - 36
SP - 94
EP - 109
JO - Nucleic Acids Research
JF - Nucleic Acids Research
IS - 1
ER -