BIOC 4580 Lecture Notes - Lecture 18: Lipid Bilayer, Antiporter, Archaea
26 Feb 2017
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Proton-induced rotation & binding change mechanism of atp synthesis. The fof1-atp synthase can function as an fof1-atpase and is a molecular motor (rotor + stator) The multimeric c-ring comprises two proton half-channels and rotates within the membrane. The atp synthesis reaction is readily reversible and involves a pentacovalent phosphate intermediate as shown by 18o isotope exchange experiments. The binding change model involves different conformational states for each of the 3 -subunits. The proton gradient also drives transport systems for the metabolites in a loose complex termed the. Uncoupling (e. g. , via ucp) of proton motive force from atp synthesis generates heat and occurs in brown adipose tissue. The fofi-atp synthase (atpase) is similar in part to dna helicases and bacterial flagellar rotors, and evolved by modular evolution. Chemical h+ concentration gradient dph (lower in im space) Electrical membrane potential dy (-ve inside) D h+ = dy + ( 2. 303rt / f ) dph.
