TY - JOUR
T1 - A molecular throttle
T2 - The recombination hotspot χ controls DNA translocation by the RecBCD helicase
AU - Spies, Maria
AU - Bianco, Piero R.
AU - Dillingham, Mark S.
AU - Handa, Naofumi
AU - Baskin, Ronald J.
AU - Kowalczykowski, Stephen C.
N1 - Funding Information:
We are grateful to Dr. Ichizo Kobayashi for providing materials for the λ DNA construction and to the members of the Kowalczykowski laboratory for their critical reading of the manuscript. This work was supported by funding from the National Institute of Health grants GM-41347 and GM-64745 to S.C.K., by the American Cancer Society Postdoctoral Fellowship PF-02-116-01-GMC to M.S., by the National Science Foundation's Center for Biophotonics, an NSF Science and Technology Center managed by the University of California, Davis, under Cooperative Agreement Number PHY 0120999 to R.J.B. and S.C.K., by a Wellcome Trust Traveling Research Fellowship to M.S.D., and by JSPS Postdoctoral Fellowship for Research Abroad to N.H.
PY - 2003/9/5
Y1 - 2003/9/5
N2 - 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 χ (5′-GCTGGTGG-3′), which is recognized in cis by the translocating enzyme. When RecBCD enzyme encounters χ, the intensity and polarity of its nuclease activity are changed, and the enzyme gains the ability to load RecA protein onto the χ-containing, unwound single-stranded DNA. Here, we show that interaction with χ also affects translocation by RecBCD enzyme. By observing translocation of individual enzymes along single molecules of DNA, we could see RecBCD enzyme pause precisely at χ. Furthermore, and more unexpectedly, after pausing at χ, the enzyme continues translocating but at approximately one-half the initial rate. We propose that interaction with χ results in an enzyme in which one of the two motor subunits, likely the RecD motor, is uncoupled from the holoenzyme to produce the slower translocase.
AB - 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 χ (5′-GCTGGTGG-3′), which is recognized in cis by the translocating enzyme. When RecBCD enzyme encounters χ, the intensity and polarity of its nuclease activity are changed, and the enzyme gains the ability to load RecA protein onto the χ-containing, unwound single-stranded DNA. Here, we show that interaction with χ also affects translocation by RecBCD enzyme. By observing translocation of individual enzymes along single molecules of DNA, we could see RecBCD enzyme pause precisely at χ. Furthermore, and more unexpectedly, after pausing at χ, the enzyme continues translocating but at approximately one-half the initial rate. We propose that interaction with χ results in an enzyme in which one of the two motor subunits, likely the RecD motor, is uncoupled from the holoenzyme to produce the slower translocase.
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U2 - 10.1016/S0092-8674(03)00681-0
DO - 10.1016/S0092-8674(03)00681-0
M3 - Article
C2 - 13678587
AN - SCOPUS:0141540814
SN - 0092-8674
VL - 114
SP - 647
EP - 654
JO - Cell
JF - Cell
IS - 5
ER -