title: RHAU helicase stabilizes G4 in its nucleotide-free state and destabilizes G4 upon ATP hydrolysis.
abstract: The DEAH-box ATP-dependent RHAU helicases specifically unfold RNA and DNA G-quadruplexes (G4s). However, it remains unclear how the RHAU's G4 unfolding activity is coupled to different stages of the ATPase cycle. Here, using a single-molecule manipulation approach, we show that binding of Drosophila RHAU stabilizes an intramolecularly folded parallel DNA G4 against mechanical unfolding in its nucleotide-free and in its AMP-PNP or ADP bound states, while it destabilizes the G4 when coupled to ATP hydrolysis. Importantly, our results show that the ADP·AlF[Formula: see text]-bound RHAU does not stabilize the G4. We also found that both a single-stranded 3' DNA tail and the RSM domain of RHAU that binds specifically to the G4 structure, are dispensable for the stabilization of the G4, but both are required for G4 destabilization. Our study provides the first evidence that the unfolding kinetics of a G-quadruplex can be modulated by different nucleotide-bound states of the helicase.
authors.affiliation: Mechanobiology Institute, National University of Singapore, 117411, Singapore.
authors.forename: Huijuan
authors.initials: H
authors.lastname: You
authors.affiliation: NTU Institute of Structural Biology, Nanyang Technological University, 636921, Singapore.
authors.forename: Simon
authors.initials: S
authors.lastname: Lattmann
authors.affiliation: NTU Institute of Structural Biology, Nanyang Technological University, 636921, Singapore DRhodes@ntu.edu.sg.
authors.forename: Daniela
authors.initials: D
authors.lastname: Rhodes
authors.affiliation: Mechanobiology Institute, National University of Singapore, 117411, Singapore phyyj@nus.edu.sg.|Department of Physics, National University of Singapore, 117542, Singapore.
authors.forename: Jie
authors.initials: J
authors.lastname: Yan
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000818:Animals; D003001:Cloning, Molecular; D053487:DEAD-box RNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D054856:G-Quadruplexes; D015870:Gene Expression; D006801:Humans; D006868:Hydrolysis; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D060526:Magnetic Fields; D052898:Optical Tweezers; D011485:Protein Binding; D000072417:Protein Domains; D012313:RNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000072760:Single Molecule Imaging; D013816:Thermodynamics
chemical_list: D029721:Drosophila Proteins; D007527:Isoenzymes; D011994:Recombinant Proteins; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D012313:RNA; D000255:Adenosine Triphosphate; D004247:DNA; C466988:DHX36 protein, human; D053487:DEAD-box RNA Helicases