Abstract

ATP synthase is the primary producer of adenosine triphosphate (ATP), a primary energy storage molecule in cells that is used in a variety of cellular processes. ATP synthase functions by using the proton gradient present across the cellular membrane to power a series of conformational changes resulting in the synthesis of ATP. E. coli ATP synthase has two major parts, F1 and F0, connected by the gamma stalk. F0 is membrane embedded, and consists of subunits a, b, and ten copies of subunit c, typically referred to as the c-ring. High energy protons enter through a half channel in subunit a and are passed into the c-ring, which rotates in a way that has protons exit on the low energy side of the membrane through a second half-channel. Recent studies have shown mutations of residues in the half-channels can severely impact the functionality of the synthase itself, making these residues potentially important to structure. Studies have also shown residues Y73 and F76 on the ion channel are potential mutation sites, which has since been confirmed with cystine mutations at Y73 and F76. Valine, serine, and lysine mutants have been made and tested for Y73 to help determine whether size and hydrophobicity are factors in functionality. Results showed size, and potentially hydrogen bonding, to be strong factors in functionality at this site. The next step is to make and test the same set of mutants at F76 and compare results to Y73.

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