Fork sensing and strand switching control antagonistic activities of RecQ helicases
Daniel Klaue,Daniela Kobbe,Felix E. Kemmerich,Alicja Kozikowska,Holger Puchta,Ralf Seidel,Ralf Seidel +6 more
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TLDR
This work investigates the DNA unwinding of RecQ helicases from Arabidopsis thaliana, AtRECQ2 and AtRECZ3 at the single-molecule level using magnetic tweezers and provides a simple explanation for how different biological activities can be achieved by rather similar members of the RecQ family.Abstract:
RecQ helicases have essential roles in maintaining genome stability during replication and in controlling double-strand break repair by homologous recombination. Little is known about how the different RecQ helicases found in higher eukaryotes achieve their specialized and partially opposing functions. Here, we investigate the DNA unwinding of RecQ helicases from Arabidopsis thaliana, AtRECQ2 and AtRECQ3 at the single-molecule level using magnetic tweezers. Although AtRECQ2 predominantly unwinds forked DNA substrates in a highly repetitive fashion, AtRECQ3 prefers to rewind, that is, to close preopened DNA forks. For both enzymes, this process is controlled by frequent strand switches and active sensing of the unwinding fork. The relative extent of the strand switches towards unwinding or towards rewinding determines the predominant direction of the enzyme. Our results provide a simple explanation for how different biological activities can be achieved by rather similar members of the RecQ family.read more
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Journal ArticleDOI
DNA repair meets climate change.
Annika Dorn,Holger Puchta +1 more
TL;DR: It is demonstrated that there is crosstalk between heat stress and genotoxic stress in Arabidopsis, and for the first time a specific temperature-dependent DNA damage response could be documented in plants.
Book ChapterDOI
Simultaneous Mechanical and Fluorescence Detection of Helicase-Catalyzed DNA Unwinding.
TL;DR: This method allows for the simultaneous detection of displacement, force and fluorescence signals of a single DNA molecule during unwinding in real time, leading to the discovery of a distinct bidirectional unwinding mode of BLM that is activated by a single-stranded DNA binding protein called replication protein A (RPA).
Posted ContentDOI
HERC2 promotes BLM and WRN to suppress G-quadruplex DNA
Wenwen Wu,Nana Rokutanda,Jun Takeuchi,Yongqiang Lai,Reo Maruyama,Yukiko Togashi,Hiroyuki Nishikawa,Naoko Arai,Yasuo Miyoshi,Nao Suzuki,Yasushi Saeki,Keiji Tanaka,Tomohiko Ohta +12 more
TL;DR: Overall, HERC2 is a master regulator of G4 suppression and affects the sensitivity of cells to G4 stabilizing compounds, telomestatin and pyridostatin.
Posted ContentDOI
Competing interactions modulate the activity of Sgs1 during DNA end resection
TL;DR: The dynamics of DNA unwinding by Sgs1 at the single molecule level is resolved and its regulation by Dna2, the single-stranded DNA binding protein RPA and the Top3-Rmi1 complex is investigated, indicating that during end resection the proteins form a physical complex and couple their activities.
References
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Journal ArticleDOI
Structure and mechanism of helicases and nucleic acid translocases.
TL;DR: This review sets out to define a nomenclature for helicase and translocase enzymes based on current knowledge of sequence, structure, and mechanism, and delineate six superfamilies of enzymes, with examples of crystal structures where available.
Journal ArticleDOI
Crystal structures of complexes of PcrA DNA helicase with a DNA substrate indicate an inchworm mechanism.
TL;DR: Two different structures of PcrA DNA helicase complexed with the same single strand tailed DNA duplex are determined, providing snapshots of different steps on the catalytic pathway, providing evidence against an "active rolling" model for helicase action but are instead consistent with an "inchworm" mechanism.
Journal ArticleDOI
Hepatitis C virus NS3 RNA helicase domain with a bound oligonucleotide: the crystal structure provides insights into the mode of unwinding
Joseph L. Kim,Morgenstern Kurt A,James P. Griffith,Maureen D. Dwyer,John A. Thomson,Murcko Mark A,Chao Lin,Paul R. Caron +7 more
TL;DR: The structure of the HCV NS3 RNA helicase domain complexed with a single-stranded DNA oligonucleotide has been solved to 2.2 A resolution and is a member of a superfamily of helicases, termed superfamily II.
Journal ArticleDOI
RecQ helicases: multifunctional genome caretakers
Wai Kit Chu,Ian D. Hickson +1 more
TL;DR: This Review discusses how these proteins might suppress genomic rearrangements, and therefore function as 'caretaker' tumour suppressors.
Journal ArticleDOI
UvrD Helicase Unwinds DNA One Base Pair at a Time by a Two-Part Power Stroke
Jae Young Lee,Wei Yang +1 more
TL;DR: A series of crystal structures of the UvrD helicase complexed with DNA and ATP hydrolysis intermediates reveal that ATP binding alone leads to unwinding of 1 base pair by directional rotation and translation of the DNA duplex, and ADP and Pi release leads to translocation of the developing single strand.