Binding of G-quadruplexes to the N-terminal Recognition Domain of the RNA Helicase Associated with AU-rich Element (RHAU)

作者：Meier Markus; Patel Trushar R; Booy Evan P; Marushchak Oksana; Okun Natalie; Deo Soumya; Howard Ryan; McEleney Kevin; Harding Stephen E; Stetefeld Joerg^*; McKenna Sean A

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2013, 288(49): 35014-35027.

DOI：10.1074/jbc.M113.512970

• DNA Helicase
• RNA-binding Protein
• RNA Helicase
• RNA-Protein Interaction
• X-ray Scattering
• DHX36
• G-quadruplex
• G4R1
• RHAU

Background: The helicase RHAU requires an N-terminal extension to bind quadruplex structures. Results: This extension adopts an elongated shape and interacts with the guanine tetrad face of quadruplexes. Conclusion: We provide a basis for the understanding of quadruplex binding by the N-terminal domain. Significance: The N-terminal region does not require the 2-OH of the ribose to mediate the protein-quadruplex interaction. %26lt;br%26gt;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) RHAU(53-105) 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.

• 出版日期2013-12-6