Specialized lambda transducing phage DNA containing the unc region of the Escherichia coli chromosome was used as template to direct an in vitro transcription/translation system. The results demonstrated synthesis of seven of the eight polypeptides of the proton translocating ATPase of this organism. The three polypeptides a, b, and c, constituting the F0 portion of the complex, were resolved by sodium dodecyl sulfatepolyacrylamide gel analysis and have apparent molecular weights (Mr = 24,000, 18,000, and 8,000-9,000) similar to the corresponding proteins produced in vivo. In addition, the alpha, beta, delta, and epsilon polypeptides of the F1 portion of the ATPase were also detected and their molecular weights correspond to the in vivo peptides. A 4.3-kilobase HindIII-generated lambda unc DNA fragment was cloned onto plasmid vectors and was demonstrated to contain the genes for the three F0 and two of the F1 (alpha, delta) subunits. In addition, the polypeptides synthesized in vitro were precipitable with antibody prepared against purified F1.