title: Fo-driven Rotation in the ATP Synthase Direction against the Force of F1 ATPase in the FoF1 ATP Synthase.
abstract: Living organisms rely on the FoF1 ATP synthase to maintain the non-equilibrium chemical gradient of ATP to ADP and phosphate that provides the primary energy source for cellular processes. How the Fo motor uses a transmembrane electrochemical ion gradient to create clockwise torque that overcomes F1 ATPase-driven counterclockwise torque at high ATP is a major unresolved question. Using single FoF1 molecules embedded in lipid bilayer nanodiscs, we now report the observation of Fo-dependent rotation of the c10 ring in the ATP synthase (clockwise) direction against the counterclockwise force of ATPase-driven rotation that occurs upon formation of a leash with Fo stator subunit a. Mutational studies indicate that the leash is important for ATP synthase activity and support a mechanism in which residues aGlu-196 and cArg-50 participate in the cytoplasmic proton half-channel to promote leash formation.
authors.affiliation: From the School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501.
authors.forename: James
authors.initials: J
authors.lastname: Martin
authors.affiliation: From the School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Hudson
authors.affiliation: From the School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501.
authors.forename: Tassilo
authors.initials: T
authors.lastname: Hornung
authors.affiliation: From the School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501 frasch@asu.edu.
authors.forename: Wayne D
authors.initials: WD
authors.lastname: Frasch
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000595:Amino Acid Sequence; D025243:Bacterial Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D021122:Protein Subunits; D012399:Rotation; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity
chemical_list: D029968:Escherichia coli Proteins; D021122:Protein Subunits; D000255:Adenosine Triphosphate; D025243:Bacterial Proton-Translocating ATPases; C557221:Escherichia coli Proton-Translocating ATPase
keywords: ATP Synthase; F1Fo ATPase; Molecular Motor; Nanodiscs; Proton Transport; Single-molecule Biophysics