ASSEMBLY OF THE F0-PROTON CHANNEL OF THE ESCHERICHIA-COLI F1F0-ATPASE - LOW PROTON CONDUCTANCE OF RECONSTITUTED F0-SECTORS SYNTHESIZED AND ASSEMBLED IN THE ABSENCE OF F1

Abstract

We have previously proposed that during assembly of the Escherichia coli F1F0 ATPase, the proton permeability of the F0 sector of the E. coli F1F0 ATPase is increased significantly by interactions with F1 subunits [Pati, S., & Brusilow, W. S. A. (1989) J. Biol. Chem 264, 2640-2644]. To test this model for F0 assembly, we purified F0 sectors synthesized in the presence and absence of F1 subunits and measured the abilities of these different preparations to bind purified F1 ATPase and to conduct protons when reconstituted into liposomes. The results of these studies demonstrated significant differences in proton-conducting abilities of the different F0 preparations. F0 sectors synthesized in the presence of F1 subunits were more permeable to protons than those synthesized in the absence of F1 subunits.