The research presented here suggests the importance of the extreme amino and

caborxyl termini. Although it was believed that the dimerization domain provided the

maj ority of the protein-protein interactions by allowing the formation of the b subunit

dimer (12, 13), our studies indicated that other regions of the b subunit are required for

normal assembly of a functional F1Fo ATP synthase complex due to contacts made with

other subunits in the enzyme. Though the three amino acid substitutions at the amino

terminus allowed dimerization and assembly of an intact F1Fo ATP synthase, it appears

that it' s sequence is crucial for the correct alignment of the proton channel formed by the

a and c subunits. Likewise, the final four amino acids at the carboxyl terminus is not

critical for the dimerization and partial assembly of the enzyme, however it is essential

for the binding of F1 due to it' s contacts with the 6 subunit.