Date of Award

Spring 2014

Document Type


Terms of Use

© 2014 Sangwoo Shawn Kim. All rights reserved. This work is freely available courtesy of the author. It may only be used for non-commercial, educational, and research purposes. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Chemistry & Biochemistry Department

First Advisor

Kathleen P. Howard


The M2 protein is a 97-residue membrane homotetrameric protein found on the viral coat of the Influenza A virus. M2 plays a key role in virulence of the Influenza A virus. M2 was previously shown to act as a proton channel that can acidify a virion once it has entered the cell. Recently, M2 has also been implicated in generating curvature in the cell membrane to mediate budding of new viral progeny. Furthermore, the amino acid sequence of M2 contains a cholesterol recognition amino acid consensus (CRAC) domain, which indicates that M2 may interact with cholesterol. In this thesis, site-directed spin-labeling (SDSL) electron paramagnetic resonance (EPR) is used to probe different conformations of M2TMC, a truncated version of the M2 protein. Continuous-wave EPR lineshapes suggest that multiple conformations of the protein are present in bilayers, and that the addition of cholesterol selectively stabilizes a more immobilized conformation. Saturation-recovery EPR confirms the presence of multiple conformations of the protein, and spin-spin coupling indicates that in a cholesterol-rich environment, the monomers of the protein are closer together. Spectral fitting and double electron-electron resonance EPR can both be used to approximate relative populations of different conformations. DEER also shows that each conformation has a unique set of distances. Finally, power saturation EPR suggests that in a cholesterol-rich bilayer, the spin-labels are closer to the lipid-aqueous interface. Together, these experiments comprehensively characterize the distinct conformations of the Influenza A M2 protein.

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