title: Binding of G-quadruplexes to the N-terminal recognition domain of the RNA helicase associated with AU-rich element (RHAU).
abstract: Polynucleotides containing consecutive tracts of guanines can adopt an intramolecular G-quadruplex structure where multiple planar tetrads of hydrogen-bound guanines stack on top of each other. Remodeling of G-quadruplexes impacts numerous aspects of nucleotide biology including transcriptional and translational control. RNA helicase associated with AU-rich element (RHAU), a member of the ATP-dependent DEX(H/D) family of RNA helicases, has been established as a major cellular quadruplex resolvase. RHAU contains a core helicase domain responsible for ATP binding/hydrolysis/helicase activity and is flanked on either side by N- and C-terminal extensions. The N-terminal extension is required for quadruplex recognition, and we have previously demonstrated complex formation between this domain and a quadruplex from human telomerase RNA. Here we used an integrated approach that includes small angle x-ray scattering, nuclear magnetic resonance spectroscopy, circular dichroism, and dynamic light scattering methods to demonstrate the recognition of G-quadruplexes by the N-terminal domain of RHAU. Based on our results, we conclude that (i) quadruplex from the human telomerase RNA and its DNA analog both adopt a disc shape in solution, (ii) RHAU53-105 adopts a defined and extended conformation in solution, and (iii) the N-terminal domain mediates an interaction with a guanine tetrad face of quadruplexes. Together, these data form the foundation for understanding the recognition of quadruplexes by the N-terminal domain of RHAU.
authors.affiliation: From the Departments of Chemistry and.
authors.forename: Markus
authors.initials: M
authors.lastname: Meier
authors.forename: Trushar R
authors.initials: TR
authors.lastname: Patel
authors.forename: Evan P
authors.initials: EP
authors.lastname: Booy
authors.forename: Oksana
authors.initials: O
authors.lastname: Marushchak
authors.forename: Natalie
authors.initials: N
authors.lastname: Okun
authors.forename: Soumya
authors.initials: S
authors.lastname: Deo
authors.forename: Ryan
authors.initials: R
authors.lastname: Howard
authors.forename: Kevin
authors.initials: K
authors.lastname: McEleney
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Harding
authors.forename: Jörg
authors.initials: J
authors.lastname: Stetefeld
authors.forename: Sean A
authors.initials: SA
authors.lastname: McKenna
mesh_terms: D063307:AU Rich Elements; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002942:Circular Dichroism; D053487:DEAD-box RNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D054856:G-Quadruplexes; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D019098:Telomerase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D011994:Recombinant Proteins; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase; C466988:DHX36 protein, human; D053487:DEAD-box RNA Helicases
keywords: DHX36; DNA Helicase; G-quadruplex; G4R1; RHAU; RNA Helicase; RNA-Protein Interaction; RNA-binding Protein; X-ray Scattering