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Tuesday, April 24 • 11:00am - 11:20am
Spectroscopic Study of mechanical movement in the Fo motor of E. coli ATP synthase

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F1Fo ATP synthase is present in all life and is responsible for the production of almost all adenosine triphosphate (ATP), which is one of the most prolific energy molecules that are synthesized during metabolism. Fo converts electrochemical potential into mechanical rotation, which drives conformational changes in F1 that facilitate the synthesis of ATP. The mechanism of rotation of the subunit c ring is not known, but there are currently two hypotheses. This study will look for evidence of the ratcheting mechanism of rotation, which states that the helices of subunits a and c act like mechanical gears during rotation. This mechanism would require the α-helices of subunit a that lie on the a-c interface to move during rotation. Site directed mutagenesis was used to mutate aV71C, which is located on a loop. This mutant ATP synthase was purified and then chemically modified with a spin label, which can be observed using electron paramagnetic resonance (EPR) spectroscopy. The EPR signal is sensitive to the protein environment and will provide data on the mobility of the residue to which the spin label is attached. This particular mutant appeared to be immobile in the data collected. The quality of the data will be improved by using different purification methods and comparing their efficiency. Protein purification will be optimized using varying imidazole concentrations. A new ATPase assay will be developed.


Tuesday April 24, 2018 11:00am - 11:20am PDT
123 Zeis Hall