16 research outputs found
Assembly of the Escherichia coli FoF1 ATP synthase involves distinct subcomplex formation
Role of the Asymmetry of the Homodimeric b2 Stator Stalk in the Interaction with the F1 Sector of Escherichia coli ATP Synthase
Structural organization of the V-ATPase and its implications for regulatory assembly and disassembly
Interaction with Monomeric Subunit c Drives Insertion of ATP Synthase Subunit a into the Membrane and Primes a-c Complex Formation
Engineering rotor ring stoichiometries in the ATP synthase
ATP synthase membrane rotors consist of a ring of c-subunits whose stoichiometry is constant for a given species but variable across different ones. We investigated the importance of c/c-subunit contacts by site-directed mutagenesis of a conserved stretch of glycines (GxGxGxGxG) in a bacterial c11 ring. Structural and biochemical studies show a direct, specific influence on the c-subunit stoichiometry, revealing c<11, c12, c13, c14, and c>14 rings. Molecular dynamics simulations rationalize this effect in terms of the energetics and geometry of the c-subunit interfaces. Quantitative data from a spectroscopic interaction study demonstrate that the complex assembly is independent of the c-ring size. Real-time ATP synthesis experiments in proteoliposomes show the mutant enzyme, harboring the larger c12 instead of c11, is functional at lower ion motive force. The high degree of compliance in the architecture of the ATP synthase rotor offers a rationale for the natural diversity of c-ring stoichiometries, which likely reflect adaptations to specific bioenergetic demands. These results provide the basis for bioengineering ATP synthases with customized ion-to-ATP ratios, by sequence modifications