The Evolution of RecD Outside of the RecBCD Complex

Montague, Michael; Barnes, Christian W.; Smith, Hamilton O.; Chuang, Ronald Y.; Vashee, Sanjay

doi:10.1007/s00239-009-9290-x

Cited by 19 publications

(27 citation statements)

References 51 publications

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“…Although D. radiodurans does not encode RecB and RecC homologs, it does encode RecD (DR1902). RecD is also present in the absence of RecBC in firmicutes, mollicutes, Streptomyces, and Desulfovibrio (429,521). RecD2 (RecD present in genomes lacking RecBC) differs from RecD1 by an N-terminal extension (521) and represents an ancestral form of RecD (429).…”

Section: Recombinational Processes In D Radiodurans Dna Repairmentioning

confidence: 99%

“…RecD is also present in the absence of RecBC in firmicutes, mollicutes, Streptomyces, and Desulfovibrio (429,521). RecD2 (RecD present in genomes lacking RecBC) differs from RecD1 by an N-terminal extension (521) and represents an ancestral form of RecD (429). Deinococcal RecD has a helicase activity with 5Ј-to-3Ј polarity and low processivity (556,644).…”

Section: Recombinational Processes In D Radiodurans Dna Repairmentioning

confidence: 99%

“…8). RecD is not essential for DSB repair, as the kinetics of DSB repair remain unaltered in gamma-irradiated or H 2 O 2 -stressed recD mutant cells (49,429). RecD was also proposed to take part in antioxidant processes by stimulating catalase activity and ROS scavenging in D. radiodurans (686).…”

Section: Recombinational Processes In D Radiodurans Dna Repairmentioning

confidence: 99%

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Oxidative Stress Resistance inDeinococcus radiodurans

Slade

Radman

2011

Microbiol Mol Biol Rev

650

639

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SUMMARY Deinococcus radiodurans is a robust bacterium best known for its capacity to repair massive DNA damage efficiently and accurately. It is extremely resistant to many DNA-damaging agents, including ionizing radiation and UV radiation (100 to 295 nm), desiccation, and mitomycin C, which induce oxidative damage not only to DNA but also to all cellular macromolecules via the production of reactive oxygen species. The extreme resilience of D. radiodurans to oxidative stress is imparted synergistically by an efficient protection of proteins against oxidative stress and an efficient DNA repair mechanism, enhanced by functional redundancies in both systems. D. radiodurans assets for the prevention of and recovery from oxidative stress are extensively reviewed here. Radiation- and desiccation-resistant bacteria such as D. radiodurans have substantially lower protein oxidation levels than do sensitive bacteria but have similar yields of DNA double-strand breaks. These findings challenge the concept of DNA as the primary target of radiation toxicity while advancing protein damage, and the protection of proteins against oxidative damage, as a new paradigm of radiation toxicity and survival. The protection of DNA repair and other proteins against oxidative damage is imparted by enzymatic and nonenzymatic antioxidant defense systems dominated by divalent manganese complexes. Given that oxidative stress caused by the accumulation of reactive oxygen species is associated with aging and cancer, a comprehensive outlook on D. radiodurans strategies of combating oxidative stress may open new avenues for antiaging and anticancer treatments. The study of the antioxidation protection in D. radiodurans is therefore of considerable potential interest for medicine and public health.

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Section: Recombinational Processes In D Radiodurans Dna Repairmentioning

confidence: 99%

Section: Recombinational Processes In D Radiodurans Dna Repairmentioning

confidence: 99%

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Oxidative Stress Resistance inDeinococcus radiodurans

Slade

Radman

2011

Microbiol Mol Biol Rev

650

639

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“…The SF1B helicases have members present in systems from bacteriophages to human (13)(14)(15)(16). SF1B helicases have clear roles in genome maintenance, although members of this family have not been nearly as well studied in vitro or in vivo as their SF1A helicase counterparts.…”

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confidence: 99%

RecD2 Helicase Limits Replication Fork Stress in Bacillus subtilis

et al. 2014

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bDNA helicases have important roles in genome maintenance. The RecD helicase has been well studied as a component of the heterotrimeric RecBCD helicase-nuclease enzyme important for double-strand break repair in Escherichia coli. Interestingly, many bacteria lack RecBC and instead contain a RecD2 helicase, which is not known to function as part of a larger complex. Depending on the organism studied, RecD2 has been shown to provide resistance to a broad range of DNA-damaging agents while also contributing to mismatch repair (MMR). Here we investigated the importance of Bacillus subtilis RecD2 helicase to genome integrity. We show that deletion of recD2 confers a modest increase in the spontaneous mutation rate and that the mutational signature in ⌬recD2 cells is not consistent with an MMR defect, indicating a new function for RecD2 in B. subtilis. To further characterize the role of RecD2, we tested the deletion strain for sensitivity to DNA-damaging agents. We found that loss of RecD2 in B. subtilis sensitized cells to several DNA-damaging agents that can block or impair replication fork movement. Measurement of replication fork progression in vivo showed that forks collapse more frequently in ⌬recD2 cells, supporting the hypothesis that RecD2 is important for normal replication fork progression. Biochemical characterization of B. subtilis RecD2 showed that it is a 5=-3= helicase and that it directly binds single-stranded DNA binding protein. Together, our results highlight novel roles for RecD2 in DNA replication which help to maintain replication fork integrity during normal growth and when forks encounter DNA damage.

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“…For this reason, the D. radiodurans RecD protein, and close protein relatives found in a number of other bacteria, have been named RecD2 (14). The in vivo function of D. radiodurans RecD2 is not clear, but recD2 mutant cells are 100 -1000 times more sensitive than wild type to the cytotoxic effect of UV light, gamma irradiation, and hydrogen peroxide (15)(16)(17).…”

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confidence: 99%

Kinetics of DNA Unwinding by the RecD2 Helicase from Deinococcus radiodurans

Shadrick

Julin

2010

Journal of Biological Chemistry

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RecD2 from Deinococcus radiodurans is a superfamily 1 DNA helicase that is homologous to the Escherichia coli RecD protein but functions outside the context of RecBCD enzyme. We report here on the kinetics of DNA unwinding by RecD2 under single and multiple turnover conditions. There is little unwinding of 20-bp substrates by preformed RecD2-dsDNA complexes when excess ssDNA is present to trap enzyme molecules not bound to the substrate. A shorter 12-bp substrate is unwound rapidly under single turnover conditions. The 12-bp unwinding reaction could be simulated with a mechanism in which the DNA is unwound in two kinetic steps with rate constant of k unw ‫؍‬ 5.5 s ؊1 and a dissociation step from partially unwound DNA of Deinococcus radiodurans is a Gram-positive bacterium that is extremely resistant to the lethal effects of ionizing radiation, ultraviolet light, oxidants, and dessication. It is widely studied as a model for organisms that are highly resistant to these agents, and for general understanding of how these agents affect living organisms. There has been much recent work on the physiological attributes, enzymes, and enzymatic pathways that contribute to its extraordinary ability to survive under extreme conditions (reviewed in Refs. 1-3). Double-strand DNA breaks (DSBs) 2 can arise in cells after treatment with ionizing radiation, oxidizing agents, and during desiccation (4), and they are lethal if unrepaired. D. radiodurans has the capacity to recover from hundreds of radiationinduced DSBs (1, 5). The enzymatic machinery that it uses to repair DSBs is not fully understood. DSB repair in E. coli and other bacteria requires the RecBCD helicase/nuclease to initiate the repair by processing broken DNA ends and loading the RecA recombinase (6, 7). DSB repair in D. radiodurans is thought to involve similar processing of the DNA ends (5, 8), and the repair is dependent on RecA (5, 9). However, D. radiodurans lacks homologues of RecB and RecC (10), and so the identity of the helicase(s) and nuclease(s) that process broken DNA ends are not clear. Recent work has indicated that the RecJ exonuclease and other enzymes of the RecF pathway may be important for DSB repair in D. radiodurans (11,12).Interestingly, D. radiodurans does have a homologue of the RecD subunit of the RecBCD enzyme found in Escherichia coli and other bacteria (10). Sequence analysis shows that the D. radiodurans RecD shares with the RecD subunits seven short amino acid motifs that are conserved in Superfamily 1 (SF1) DNA and RNA helicases (13). However, the D. radiodurans protein is larger than that from E. coli, with an N-terminal extension whose amino acid sequence is poorly conserved. For this reason, the D. radiodurans RecD protein, and close protein relatives found in a number of other bacteria, have been named RecD2 (14). The in vivo function of D. radiodurans RecD2 is not clear, but recD2 mutant cells are 100 -1000 times more sensitive than wild type to the cytotoxic effect of UV light, gamma irradiation, and hydrogen peroxide (15-17)....

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The Evolution of RecD Outside of the RecBCD Complex

Cited by 19 publications

References 51 publications

Oxidative Stress Resistance inDeinococcus radiodurans

Oxidative Stress Resistance inDeinococcus radiodurans

RecD2 Helicase Limits Replication Fork Stress in Bacillus subtilis

Kinetics of DNA Unwinding by the RecD2 Helicase from Deinococcus radiodurans

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