The RecOR proteins modulate RecA protein function at 5' ends of single-stranded DNA

Bork, Julie M.; Cox, Michael M.; Inman, Ross B.

doi:10.1093/emboj/20.24.7313

Cited by 116 publications

(122 citation statements)

References 51 publications

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“…Earlier functional studies suggested that RecR is involved in protein-protein interactions in recombination mediation reaction, because it forms complexes either with RecO or with RecF, and potentially with RecA (32,33,51). A DNA clamp function of RecR was suggested by structural studies of D. radiodurans RecR (45,46).…”

Section: Discussionmentioning

confidence: 99%

RecR-mediated Modulation of RecF Dimer Specificity for Single- and Double-stranded DNA

Makharashvili

Tian

Королева

et al. 2009

Journal of Biological Chemistry

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Section: Discussionmentioning

confidence: 99%

RecR-mediated Modulation of RecF Dimer Specificity for Single- and Double-stranded DNA

Makharashvili

Tian

Королева

et al. 2009

Journal of Biological Chemistry

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“…The model proposed for RecO facilitation of RecA rapid nucleation onto ssDNA or SsbA-coated ssDNA differs from the models proposed for the activity of the RecOR Eco complex. Here, RecR Eco interacts with the RecA nucleoprotein filament and only the interaction of RecR Eco with RecO Eco enhances the nucleation of RecA Eco onto ssDNA, when added prior to SSB Eco (14,15,55). The RecOR Eco complex is also needed to facilitate slow loading of RecA Eco onto SSB Eco -coated ssDNA (16).…”

mentioning

confidence: 99%

Bacillus subtilis RecO Nucleates RecA onto SsbA-coated Single-stranded DNA

Manfredi¹,

Carrasco

Ayora

et al. 2008

Journal of Biological Chemistry

113

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Subsaturating amounts of Bacillus subtilis SsbA, independently of the order of addition, partially inhibit the singlestranded DNA-dependent dATPase activity of RecA. This negative effect is fully overcome when a substoichiometric amount of RecO is added. SsbA added prior to RecA does not stimulate the dATP-dependent DNA strand exchange activity; however, added after RecA it enhances the extent of strand exchange. The addition of RecO stimulates RecA-mediated joint molecule formation, although it limits the accumulation of final recombination products. Thus we suggest that RecO has a dual activity: RecO acts as a RecA mediator enabling RecA to utilize SsbAcoated single-stranded DNA as a polymerization substrate and controls RecA-mediated DNA strand exchange by limiting its extent. We herein discuss the possible mechanisms of RecO involvement in the regulation of double strand break repair and genetic transformation.

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“…The nucleation barrier represented by SSB is overcome by the RecO and RecR proteins (48,49), perhaps with help from the RecF protein (50). Another protein, DinI, stabilizes RecA protein filaments and prevents filament dissociation (51).…”

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confidence: 99%

SSB Antagonizes RecX-RecA Interaction

Baitin

Gruenig

Cox

2008

Journal of Biological Chemistry

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The bacterial RecA protein is the prototype of a nearly ubiquitous class of recombinase proteins (1-11). These enzymes promote DNA strand exchange reactions that lie at the heart of all recombination and recombinational DNA repair processes (11-16). The recombinase forms a right-handed helical filament, usually on single-stranded DNA (ssDNA).2 A homologous duplex DNA is then aligned with this bound single strand, and one strand (the one complementary to the bound single strand) is transferred from the duplex substrate to form a new duplex within the filament. This process is used to reconstruct stalled replication forks, repair double strand breaks, facilitate meiotic cross-overs in eukaryotes, and facilitate genetic exchanges of many types in almost every organism. Typical reactions are illustrated in Fig. 1.The assembly and disassembly of RecA protein filaments on DNA has been studied in some detail, although understanding is not complete. Nucleation occurs most readily on ssDNA. There are discrete nucleation and extension phases in the assembly process, with extension proceeding primarily 5Ј to 3Ј relative to the ssDNA (17, 18). Disassembly also proceeds primarily 5Ј to 3Ј, with monomeric subunits being added on one end and subtracted from the other (19,20). Dissociation at the disassembly end is coupled to ATP hydrolysis (21,22).RecA-promoted reactions are important to cell viability. Escherichia coli strains lacking a functional recA gene are viable but highly sensitive to DNA-damaging agents (23-25). Recombinational DNA repair is thus important in bacteria, especially for the repair of stalled or collapsed replication forks (26 -30). However, recombination can also have deleterious consequences and must be regulated. Recombination between repeated sequences in the genome, for example, could result in the deletion of essential genes.In the past decade, multiple new RecA regulatory mechanisms have been elucidated. The expression of the recA gene is regulated as part of the SOS response (31-35). The native RecA protein is auto-regulated by the 17 amino acid residues at its own C terminus, because virtually every RecA activity is enhanced when those 17 amino acids are deleted (36 -41). Finally, RecA function is regulated by a growing array of regulatory proteins.There are at least eight proteins in a typical E. coli cell that modulate RecA protein function to some extent. Much of the regulation is focused on RecA filament assembly and disassembly. One modulator of RecA filament dynamics is SSB. SSB strongly inhibits the nucleation phase of RecA filament assembly (42) but stimulates the extension phase, removing secondary structure in ssDNA that would otherwise impede filament growth (43-46). Although ordinarily SSB protein prevents filament nucleation, single RecA monomers can easily be added to an existing filament and displace SSB from DNA at the rate of filament extension (47).Additional proteins affect other aspects of RecA protein filament function, often by interacting directly with RecA. The nucleation ...

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The RecOR proteins modulate RecA protein function at 5' ends of single-stranded DNA

Cited by 116 publications

References 51 publications

RecR-mediated Modulation of RecF Dimer Specificity for Single- and Double-stranded DNA

RecR-mediated Modulation of RecF Dimer Specificity for Single- and Double-stranded DNA

Bacillus subtilis RecO Nucleates RecA onto SsbA-coated Single-stranded DNA

SSB Antagonizes RecX-RecA Interaction

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