Mutational analysis of a conserved positive charge in the c-ring of E. coli ATP synthase.

FF ATP synthase is a ubiquitous molecular motor that utilizes a rotary mechanism to synthesize adenosine triphosphate (ATP), the fundamental energy currency of life. The membrane-embedded F motor converts the electrochemical gradient of protons into rotation, which is then used to drive the conformational changes in the soluble F motor that catalyze ATP synthesis. In E.

Unimolecular HBr and HF Elimination Reactions of Vibrationally Excited CHCHBr and CDCHFBr: Identification of the 1,1-HBr Elimination Reaction from CDCHFBr and Search for the CD(F)C:HBr Adduct.

Chemical activation experiments and computational methods have been used to study the unimolecular reactions of CHCHBr and CDCHFBr with 90 and 93 kcal mol of vibrational energy, respectively. The four-centered elimination reactions of HBr and DBr are the dominant reactions; however, 2,1-DF, 1,1-HBr, and 1,1-HF reactions are also observed from CDCHFBr. The main focus was to search for the role of the CD(F)C:HBr adduct in the 1,1-HBr elimination for comparison with carbene adducts in 1,1-HX(Y) elimination from RCHXY (X,Y = Cl and F) molecules.

Experimental and Computational Studies of Unimolecular 1,1-HX (X = F, Cl) Elimination Reactions of CDCHFCl: Role of Carbene:HF and HCl Adducts in the Exit Channel of RCHFCl and RCHCl Reactions.

The gas-phase unimolecular reactions of CDCHFCl molecules with 94 kcal mol of vibrational energy have been studied by the chemical-activation experimental technique and by electronic-structure computations. Products from the reaction of CDCHFCl molecules, formed by the recombination of CD and CHFCl radicals in a room temperature bath gas, were measured by gas chromatography-mass spectrometry. The 2,1-DCl (81%) and 1,1-HCl (17%) elimination reactions are the principal processes, but 2,1-DF and 1,1-HF elimination reactions also are observed.