Talk abstracts
Talk on Friday 02:15-02:30pm submitted by Jeff Levengood
Utilization of high-pressure NMR for the study of an intrinsically disordered domain of hnRNP A1
Jeffrey D. Levengood (Department of Chemistry, Case Western Reserve University), Jake Peterson (Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University), Julien Roche (Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University), Blanton S. Tolbert (Department of Chemistry, Case Western Reserve University)
Abstract:
The hnRNP A1 protein is involved in numerous processes of nascent RNA transcripts. These roles include, but are not limited to, translational control, splicing regulation, and mRNA stabilization. The protein performs its functions by first binding the RNA at a high affinity site before recruiting other proteins to aid in its RNA processing activities.
hnRNP A1 is composed of three domains, two structurally identical RRMs that form the nucleic acid binding protein UP1, and a disordered, glycine rich C-terminal domain (G-CTD). As the more structured domain, UP1 has been studied extensively. Its RNA binding properties have been examined through numerous biochemical and biophysical methods. Its structure, both free and bound, has been determined through NMR, X-ray crystallography, and small-angle X-ray scattering (SAXS).
In contrast to UP1, the G-CTD has not been very well characterized. However, its roles in hnRNP A1 activity requires that it be studied with just as much detail as UP1. The G-CTD is responsible for assembling the multi-protein complexes the protein utilizes to carry out its various functions. It has been shown to be a low complexity domain (LCD) capable of mediating liquid-liquid phase separation (LLPS). This partitioning leads to the formation of stress granules, cytosolic bodies which are believed to be formed by mRNAs stalled in translation.
The utilization of SAXS and high-pressure NMR has revealed the LC domain, at standard conditions, adopts a disordered, but compact conformation that is stabilized by polar and electrostatic interactions. The application of pressure increases solvent density, resulting in a disruption of the intra-protein interactions and the compact nature of the domain. The application of high pressure might also stabilize helical formation in the domain. The extended high-pressure conformation potentially reveals attributes of the domain which play a role in phase separation.
Keywords: RRM, IDP, high-pressure NMR