Chemistry Seminar - Structural and biophysical characterization of splicing-associated assemblies of the SMN protein
Structural and biophysical characterization of splicing-associated assemblies of the SMN proteinKaylee Mathews ‘16Biochemistry BS Alumna 2016Ph.D. Candidate in Molecular Biology, Cell Biology, and BiochemistryBrown UniversityAbstract:Survival of motor neuron (SMN/Gemin1) plays an essential role in small nuclear ribonucleoprotein (snRNP) assembly and localizes to phase-separated bodies in both the nucleus and cytoplasm. Prior to snRNP assembly, SMN must self-assemble via its YG box, and missense mutations in SMN near the YG box cause a severe, neuromuscular degenerative disease called spinal muscular atrophy (SMA). However, the structure of the functional SMN oligomer and the mechanistic effect of the mutations on YG box assembly remains unknown. Here, we present a biophysical and biochemical characterization of the wild-type SMN oligomer. We have identified thermostable α-helical character in the C-terminal domain (CTD) of SMN using circular dichroism (CD) spectroscopy. We have also discovered the presence of a second assembly event mediated by the proline-rich region of SMN using nuclear magnetic resonance (NMR) spectroscopy. In addition, we show using size exclusion chromatography coupled to multi-angle light scattering (SEC-MALS) that the stoichiometry of the oligomer is much larger than has been previously reported in the literature. Finally, we have begun to utilize methyl-TROSY NMR experiments to structurally characterize the SMN oligomer. This work provides new data allowing us to further probe the normal structure of SMN and its dysfunction in disease.Speaker Bio:Kaylee Mathews is a Ph.D. candidate in Molecular Biology, Cell Biology, and Biochemistry at Brown University where she works in the lab of Dr. Nicolas Lux Fawzi. She uses nuclear magnetic resonance (NMR) spectroscopy to study the structure and interactions of proteins implicated in neurodegenerative disease. In addition to her research, Kaylee is very active in her graduate program where she serves on committees ranging in topic from first-year mentoring to organization of structural biology seminars. Before matriculating at Brown University, Kaylee attended Rochester Institute of Technology and earned her Bachelor of Science in Biochemistry in 2016. At RIT, she worked with Drs. Lea Vacca Michel, George Thurston, and Jeffrey Mills where she studied the interactions between lens crystallin proteins using NMR.
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