ATP-SYNTHETASE OF ESCHERICHIA-COLI-K12 - PURIFICATION OF THE ENZYME AND RECONSTITUTION OF ENERGY-TRANSDUCING ACTIVITIES

The ATP synthetase of E. coli K12 was purified by a simple procedure. The dicyclohexylcarbodiimide-sensitive ATPase activity was enriched 21-fold. The ATP synthetase preparation contained the 8 polypeptides (.alpha., .beta., .gamma., a, .delta., b, .epsilon., c) of the enzyme and a residual contamination (4% of the total protein) as shown by dodecylsulfate/polyacrylamide electrophoresis. The polypeptide c was specifically labeled with [14C]dicyclohexylcarbodiimide. Energy-transducing activities were reconstituted from soybean phospholipids and the purified enzyme. The proteoliposomes exhibited a significantly higher ATP-32Pi exchange activity and a higher proton-translocating activity as compared to the untreated membranes.