Assembly of bacteriophage T4 tail fibers. IV. Subunit composition of tail fibers and fiber precursors

Using a novel purification procedure, the protein composition of the tail fibers of bacteriophage T4 has been determined. Fibers contain four proteins whose molecular weights, as estimated by sodium dodecyl sulfate/acrylamide gel electrophoresis, are 150,000, 125,000, 40,000 and 24,000. The two largest proteins have been previously identified as the products of genes 34 (P34) and 37 (P37), respectively (King and Laemmli, 1971; Ward and Dickson, 1971). The two smaller proteins have now been identified as the products of genes 35 (P35) and 36 (P36), respectively. The products of the two other known phage genes required for fiber assembly, 38 and 57, have been identified as non-structural phage proteins with molecular weights of 26,000 and 10,000, respectively.