Process of Infection with Bacteriophage φX174 XXXIV. Kinetics of the Attachment and Eclipse Steps of the Infection

The products of {varphi}X cistrons II, III, and VII are demonstrated to affect the attachment of the phage to its host Escherichia coli C; therefore, by inference, these cistrons influence, directly or indirectly, the structure of proteins in the virus particle. Two of the mutations which alter attachment kinetics, ts79 in cistron III and h in cistron VII, also affect the electrophoretic mobility of the virus and emphasize the role of charge in the attachment interaction with the host. The kinetics for attached phage to go into "eclipse" are first-order and biphasic; about 85% of the phage eclipse at one rate (ke = 0.86 min^–1) and the remainder do so at a distinctly lower rate (ke = 0.21 min^–1). No {varphi}X cistrons yet identified affect the eclipse process. The lowest temperature at which eclipse is detected is 19 C. The Arrhenius activation energy for phage eclipse has the high value of 36.6 kcal/mole, indicating the cooperative nature of the event