Published in Molecular Cell
In Escherichia coli, chi (5 -GCTGGTGG-3 ) is a recombination hotspot recognized by the RecBCD enzyme. Recognition of chi reduces both nuclease activity and translocation speed of RecBCD and activates RecA-loading ability. RecBCD has two motor subunits, RecB and RecD, which act simultaneously but independently. A longstanding hypothesis to explain t...
Published in Journal of Biological Chemistry
The Bacillus subtilis AddAB enzyme possesses ATP-dependent helicase and nuclease activities, which result in the unwinding and degradation of double-stranded DNA (dsDNA) upon translocation. Similar to its functional counterpart, the Escherichia coli RecBCD enzyme, it also recognizes and responds to a specific DNA sequence, referred to as Chi (chi)....
Published in Journal of Molecular Biology
In Escherichia coli, homologous recombination initiated at double-stranded DNA breaks requires the RecBCD enzyme, a multifunctional heterotrimeric complex that possesses processive helicase and exonuclease activities. Upon encountering the DNA regulatory sequence, chi, the enzymatic properties of RecBCD enzyme are altered. Its helicase activity is ...
Published in Cell
RecBCD enzyme is a heterotrimeric helicase/nuclease that initiates homologous recombination at double-stranded DNA breaks. Several of its activities are regulated by the DNA sequence chi (5 -GCTGGTGG-3 ), which is recognized in cis by the translocating enzyme. When RecBCD enzyme encounters chi, the intensity and polarity of its nuclease activity ar...
Published in Proceedings of the National Academy of Sciences
The RecBCD enzyme is a complex heterotrimeric helicase/nuclease that initiates recombination at double-stranded DNA breaks. In Escherichia coli, its activities are regulated by the octameric recombination hotspot, χ (5 -GCTGGTGG), which is read as a single-stranded DNA sequence while the enzyme is unwinding DNA at over ∼1,000 bp/s. Previous studies...
Published in Proceedings of the National Academy of Sciences
The RecBCD enzyme is important for both restriction of foreign DNA and recombinational DNA repair. Switching enzyme function from the destructive antiviral state to the productive recombinational state is regulated by the recombination hotspot, χ (5 -GCTGGTGG-3 ). Recognition of χ is unique in that it is recognized as a specific sequence within sin...
Published in Proceedings of the National Academy of Sciences
The Mre11-Rad50-Xrs2/NBS1 (MRX/N) nuclease/ATPase complex plays structural and catalytic roles in the repair of DNA double-strand breaks (DSBs) and is the DNA damage sensor for Tel1/ATM kinase activation. Saccharomyces cerevisiae Sae2 can function with MRX to initiate 5 -3 end resection and also plays an important role in attenuation of DNA damage...
Published in Journal of Biological Chemistry
Fluorescent fusion proteins are exceedingly useful for monitoring protein localization in situ or visualizing protein behavior at the single molecule level. Unfortunately, some proteins are rendered inactive by the fusion. To circumvent this problem, we fused a hyperactive RecA protein (RecA803 protein) to monomeric red fluorescent protein (mRFP1) ...
Published in Journal of Molecular Biology
In wild-type Escherichia coli, recognition of the recombination hotspot, chi (5 -GCTGGTGG-3 ), by the RecBCD enzyme is central to homologous recombination. However, in the recC* class of RecBCD mutants, stimulation of recombination by the canonical chi sequence is not detectable, but the levels of homologous recombination are nearly wild-type. In v...
Published in Nature Communications
MCM8-9 complex is required for homologous recombination (HR)-mediated repair of double-strand breaks (DSBs). Here we report that MCM8-9 is required for DNA resection by MRN (MRE11-RAD50-NBS1) at DSBs to generate ssDNA. MCM8-9 interacts with MRN and is required for the nuclease activity and stable association of MRN with DSBs. The ATPase motifs of M...
Published in Genes & Development
The RecF pathway of Escherichia coli is important for recombinational repair of DNA breaks and gaps. Here ;we reconstitute in vitro a seven-protein reaction that recapitulates early steps of dsDNA break repair using purified RecA, RecF, RecO, RecR, RecQ, RecJ, and SSB proteins, components of the RecF system. Their combined action results in process...
