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Sci Rep. 2017 Mar 7;7:43954. doi: 10.1038/srep43954.

Single-molecule studies reveal reciprocating of WRN helicase core along ssDNA during DNA unwinding.

Author information

1
College of Life Sciences, Northwest A&F University, Yangling 712100, China.
2
LBPA, IDA, ENS Cachan, CNRS, Université Paris-Saclay, Cachan F-94235, France.
3
Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
4
School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.

Abstract

Werner syndrome is caused by mutations in the WRN gene encoding WRN helicase. A knowledge of WRN helicase's DNA unwinding mechanism in vitro is helpful for predicting its behaviors in vivo, and then understanding their biological functions. In the present study, for deeply understanding the DNA unwinding mechanism of WRN, we comprehensively characterized the DNA unwinding properties of chicken WRN helicase core in details, by taking advantages of single-molecule fluorescence resonance energy transfer (smFRET) method. We showed that WRN exhibits repetitive DNA unwinding and translocation behaviors on different DNA structures, including forked, overhanging and G-quadruplex-containing DNAs with an apparently limited unwinding processivity. It was further revealed that the repetitive behaviors were caused by reciprocating of WRN along the same ssDNA, rather than by complete dissociation from and rebinding to substrates or by strand switching. The present study sheds new light on the mechanism for WRN functioning.

PMID:
28266653
PMCID:
PMC5339710
DOI:
10.1038/srep43954
[Indexed for MEDLINE]
Free PMC Article

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