Abstract:The RecA protein requires ATP or dATP for its coprotease and strand exchange activities. Other natural nucleotides, such as ADP, CTP, GTP, UTP and TTP, have little or no activation effect on RecA for these activities. We have investigated the activation mechanism, and the selectivity for ATP, by studying the effect of various nucleotides on the DNA binding and the helical structure of the RecA filament. The interaction with DNA was investigated via fluorescence measurements with a fluorescent DNA analog and fl… Show more
“…2B), and was 1.6‐fold larger than that of the complex without nucleotide. The effect of ADP on the HsRad51‐poly(dɛA) complex differs from that on the RecA‐ or XRad51‐poly(dɛA) complexes: ADP strongly decreases the fluorescence from the RecA‐poly(dɛA) complex (Ellouze et al . 1999), and does not significantly change that of the XRad51‐poly(dɛA) complex (Maeshima et al .…”
Background : Human Rad51 protein (HsRad51) is a homologue of Escherichia coli RecA protein, and involved in homologous recombination. These eukaryotic and bacterial proteins catalyse strand exchange between two homologous DNA molecules, each forming a complex with single-stranded DNA (ssDNA) and ATP as the initial step. Both proteins hydrolyse ATP; however, the role of ATP hydrolysis appears to vary between the two proteins.
“…2B), and was 1.6‐fold larger than that of the complex without nucleotide. The effect of ADP on the HsRad51‐poly(dɛA) complex differs from that on the RecA‐ or XRad51‐poly(dɛA) complexes: ADP strongly decreases the fluorescence from the RecA‐poly(dɛA) complex (Ellouze et al . 1999), and does not significantly change that of the XRad51‐poly(dɛA) complex (Maeshima et al .…”
Background : Human Rad51 protein (HsRad51) is a homologue of Escherichia coli RecA protein, and involved in homologous recombination. These eukaryotic and bacterial proteins catalyse strand exchange between two homologous DNA molecules, each forming a complex with single-stranded DNA (ssDNA) and ATP as the initial step. Both proteins hydrolyse ATP; however, the role of ATP hydrolysis appears to vary between the two proteins.
“…In vitro , other nucleotide triphosphates are competitive inhibitors of dATP‐promoted RecA coprotease activity (Weinstock and McEntee, ; Weinstock et al, ). It was suggested that the chemical nature of the nucleobase is important for the stability of the RecA‐ssDNA complex: adenine promotes strong RecA‐DNA binding, while other bases promote only weak binding, leading to enhanced dissociation of the filament (Ellouze et al, ). Of the two possible RecA filament states, only one explains the interaction between LexA and RecA that promotes LexA cleavage (VanLoock et al, ), and the efficient formation of RecA filaments in the active conformation is necessary for SOS induction (Gruenig et al, ).…”
Section: Role Of Dntp Pools In Sos Inductionmentioning
confidence: 99%
“…Little in vivo information is available about the possible role of the cellular dNTPs in RecA activation, although a number of studies have addressed the role of alternative cofactors using in vitro experiments (Phizicky and Roberts, 1981;Weinstock and McEntee, 1981;Menetski et al, 1988;Wang et al, 1988a;Ellouze et al, 1999;Wigle et al, 2006). Various (d)NTP species show different efficiencies in promoting RecA coprotease activity in vitro (Phizicky and Roberts, 1981;Weinstock et al, 1981a).…”
Section: Role Of Dntp Pools In Sos Inductionmentioning
“…Other nucleotides are available in vivo , and in vitro experiments show that RecA can bind several of them and retain at least some key functions (McEntee et al ., 1981; Weinstock et al ., 1981a,b,c; Menge and Bryant, 1988; 1992a,b). The nucleotide dATP substitutes best for ATP in vitro , and several RecA functions are enhanced when dATP replaces ATP in reaction mixtures (Menetski and Kowalczykowski, 1989; Shan et al ., 1997; Ellouze et al ., 1999; Robu et al ., 2001).…”
SummaryThe Escherichia coli SOS response to DNA damage is modulated by the RecA protein, a recombinase that forms an extended filament on single-stranded DNA and hydrolyzes ATP. The RecA K72R (recA2201) mutation eliminates the ATPase activity of RecA protein. The mutation also limits the capacity of RecA to form long filaments in the presence of ATP. Strains with this mutation do not undergo SOS induction in vivo. We have combined the K72R variant of RecA with another mutation, RecA E38K (recA730). In vitro, the double mutant RecA E38K/K72R (recA730,2201) mimics the K72R mutant protein in that it has no ATPase activity. The double mutant protein will form long extended filaments on ssDNA and facilitate LexA cleavage almost as well as wild-type, and do so in the presence of ATP. Unlike recA K72R, the recA E38K/ K72R double mutant promotes SOS induction in vivo after UV treatment. Thus, SOS induction does not require ATP hydrolysis by the RecA protein, but does require formation of extended RecA filaments. The RecA E38K/K72R protein represents an improved reagent for studies of the function of ATP hydrolysis by RecA in vivo and in vitro.
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