FUNCTIONS OF BASEPLATE COMPONENTS IN BACTERIOPHAGE-T4 INFECTION .3. FUNCTIONAL-ORGANIZATION OF THE BASEPLATE

Thermolabile (hs) mutants of bacteriophage T4 have been used to investigate the functions of tail proteins in phage adsorption. The thermolabilities of the mutants before and after conversion to urea-treated particles, which bypass the first two stages of adsorption, were examined. The conformational integrity of gene products P5, P12, P18, P25, and P48 is essential for the formation of irreversibly adsorbed, contracted phage particles. P27 is apparently irrelevant to these processes, but structurally necessary for the final stages of infection when the phage DNA enters the host. On the basis of these results, and those reported earlier (Dawes and Goldberg, Virology55, 391-396, 1973), functional regions have been delineated in the T4 baseplate. © 1979.