The structure of three bacteriophage T4 genes required for tail-tube assembly.

Three different protein molecules copurify with T4 tail tubes after the tubes are released from the baseplate by guanidine hydrochloride treatment. These tube-associated proteins (TAPs) are the products of genes 29, 48, and 54. To further investigate the structural roles that these proteins may play in T4 tail assembly we have cloned and sequenced the genes coding for these proteins and have deduced their predicted amino acid sequences. The sequence data reveal a region of amino acid sequence similarity between gp54 and the T4 tail-tube structural protein, gp19. We believe that this region of similarity is significant and consistent with the role gp54 may play in initiating T4 tail-tube polymerization.