Abstract
The energy transduction in biomembranes requires a special supramolecular structure. This structure is needed for converting proton motive energy into ATP synthesis. These biomembranes contain 4 enzyme complexes that are composed of many polypeptides. Here we describe the following 4 phenomena : 1) oligomer formation by self-assembly of the subunits, 2) incorporation of the oligomers into a lipid bilayer, 3) chaperonin-mediated formation of the oligomers and membranes, 4) coordination of the subunit biosyntheses by enhancers and the role of mitochondrial DNA.
Polypeptides translated are assembled into the membrane complexes with or without the help of chaperonins. In the case of thermophilic proteins, the reconstitutability of polypeptides is excellent ; for example, the catalytic portion of ATP synthase, α1 β1 subunit complex, was reconstituted. On the other hand, mesophilic ATP synthase requires chaperonins for its formation. The transcription of mRNAs for these polypeptides is coordinated by special enhancer and silencer. The role of polypeptides encoded by mitochondrial DNA in the molecular assembly was studied with the wild-type and mutant cells.
