Abstract
The Escherichia coli RecA protein is involved in SOS induction, DNA repair, and homologous recombination. In vitro, RecA protein serves as a co- protease to cleave LexA repressor, the repressor of the SOS regulon; in addition, RecA protein promotes homologous pairing and DNA strand exchange, steps important to homologous recombination and DNA repair. To determine if these two functions of RecA protein are competing or parallel, the effect of uncleavable LexA S119A repressor on RecA protein-dependent activities was examined. LexA S119A repressor inhibits both the single-stranded DNA (ssDNA)- dependent ATP hydrolysis and DNA strand exchange activities of RecA protein. As for wild-type LexA repressor (Rehrauer, W. M., Lavery, P. E., Palmer, E. L., Singh, R. N., and Kowalczykowski, S.C. (1996) J. Biol Chem. 271, 23865- 23873), inhibition of ATP hydrolysis is dependent upon the presence of E. coli single-stranded DNA binding (SSB) protein, arguing that LexA repressor affects the competition between RecA protein and SSB protein for ssDNA binding sites. In contrast, inhibition of DNA strand exchange activity is SSB protein-independent, suggesting that LexA S119A represser blocks a site required for DNA strand exchange. These results imply that there is a common site on the RecA protein filament for secondary DNA and LexA repressor binding and raise the possibility that the recombination and co-protease activities of the RecA protein filament are competitive.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 23874-23883 |
| Number of pages | 10 |
| Journal | Journal of Biological Chemistry |
| Volume | 271 |
| Issue number | 39 |
| DOIs | |
| State | Published - 1996 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Interaction of Escherichia coli RecA protein with LexA repressor. II. Inhibition of DNA strand exchange by the uncleavable LexA S119A repressor argues that recombination and SOS induction are competitive processes. / Harmon, Frank G.; Rehrauer, William M.; Kowalczykowski, Stephen C.
In: Journal of Biological Chemistry, Vol. 271, No. 39, 1996, p. 23874-23883.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Interaction of Escherichia coli RecA protein with LexA repressor. II. Inhibition of DNA strand exchange by the uncleavable LexA S119A repressor argues that recombination and SOS induction are competitive processes
AU - Harmon, Frank G.
AU - Rehrauer, William M.
AU - Kowalczykowski, Stephen C.
PY - 1996
Y1 - 1996
N2 - The Escherichia coli RecA protein is involved in SOS induction, DNA repair, and homologous recombination. In vitro, RecA protein serves as a co- protease to cleave LexA repressor, the repressor of the SOS regulon; in addition, RecA protein promotes homologous pairing and DNA strand exchange, steps important to homologous recombination and DNA repair. To determine if these two functions of RecA protein are competing or parallel, the effect of uncleavable LexA S119A repressor on RecA protein-dependent activities was examined. LexA S119A repressor inhibits both the single-stranded DNA (ssDNA)- dependent ATP hydrolysis and DNA strand exchange activities of RecA protein. As for wild-type LexA repressor (Rehrauer, W. M., Lavery, P. E., Palmer, E. L., Singh, R. N., and Kowalczykowski, S.C. (1996) J. Biol Chem. 271, 23865- 23873), inhibition of ATP hydrolysis is dependent upon the presence of E. coli single-stranded DNA binding (SSB) protein, arguing that LexA repressor affects the competition between RecA protein and SSB protein for ssDNA binding sites. In contrast, inhibition of DNA strand exchange activity is SSB protein-independent, suggesting that LexA S119A represser blocks a site required for DNA strand exchange. These results imply that there is a common site on the RecA protein filament for secondary DNA and LexA repressor binding and raise the possibility that the recombination and co-protease activities of the RecA protein filament are competitive.
AB - The Escherichia coli RecA protein is involved in SOS induction, DNA repair, and homologous recombination. In vitro, RecA protein serves as a co- protease to cleave LexA repressor, the repressor of the SOS regulon; in addition, RecA protein promotes homologous pairing and DNA strand exchange, steps important to homologous recombination and DNA repair. To determine if these two functions of RecA protein are competing or parallel, the effect of uncleavable LexA S119A repressor on RecA protein-dependent activities was examined. LexA S119A repressor inhibits both the single-stranded DNA (ssDNA)- dependent ATP hydrolysis and DNA strand exchange activities of RecA protein. As for wild-type LexA repressor (Rehrauer, W. M., Lavery, P. E., Palmer, E. L., Singh, R. N., and Kowalczykowski, S.C. (1996) J. Biol Chem. 271, 23865- 23873), inhibition of ATP hydrolysis is dependent upon the presence of E. coli single-stranded DNA binding (SSB) protein, arguing that LexA repressor affects the competition between RecA protein and SSB protein for ssDNA binding sites. In contrast, inhibition of DNA strand exchange activity is SSB protein-independent, suggesting that LexA S119A represser blocks a site required for DNA strand exchange. These results imply that there is a common site on the RecA protein filament for secondary DNA and LexA repressor binding and raise the possibility that the recombination and co-protease activities of the RecA protein filament are competitive.
UR - http://www.scopus.com/inward/record.url?scp=0029835784&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029835784&partnerID=8YFLogxK
U2 - 10.1074/jbc.271.39.23874
DO - 10.1074/jbc.271.39.23874
M3 - Article
C2 - 8798618
AN - SCOPUS:0029835784
VL - 271
SP - 23874
EP - 23883
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 39
ER -