Talk abstracts
Talk on Friday 02:00-02:15pm submitted by Aldrex Munsayac
Solution scattering as a structural tool for RNA and RNA:RNA complexes
Aldrex Munsayac (Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA), Wellington C. Leite (Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA), Jesse B. Hopkins (Biophysics Collaborative Access Team, Argonne National Laboratory, Lemont, IL, 60439, USA), Ian Hall (Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA), Hugh M. ONeill (Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA), Sarah C. Keane (Department of Chemistry and Biophysics Program, University of Michigan, Ann Arbor, MI, 48109, USA)
Abstract:
The formation of RNA:RNA complexes represents a critical feature in many biological processes, from gene regulation to viral replication. Structural knowledge of these RNA:RNA complexes remains central to understanding the molecular mechanisms governing their function. Despite their importance, high-resolution structural studies of RNA:RNA complexes remains challenging, accounting for less than 0.002% of the known structures in the PDB, highlighting the need for alternative approaches. Here, we describe a joint small-angle X-ray and neutron scattering (SAXS/SANS) approach to determine the global architecture of individual RNAs within an RNA:RNA complex. To develop this method, we studied a model RNA:RNA complex, based on the dimerization initiation signal (DIS) from the human immunodeficiency virus. Using SAXS, we measured the solution structures of the individual RNAs in their free state and of the overall RNA:RNA complex. With SANS, we demonstrate, as a proof-of-principle, that isotope labeling and contrast matching (CM) can be combined to probe the bound state structure of an RNA within a selectively deuterated RNA:RNA complex. Furthermore, we show that experimental scattering data can validate and improve predicted AlphaFold 3 RNA:RNA complex structures to reflect its solution structure. Our work demonstrates that in silico modeling, SAXS, and CM-SANS can be used in concert to directly analyze conformational changes within RNAs when in complex, enhancing our understanding of RNA structure in functional assemblies.
Keywords: Small-angle scattering, RNARNA complexes, RNA structure modeling