CALCIUM CONTROLS PHAGE T5 INFECTION AT THE LEVEL OF THE ESCHERICHIA-COLI CYTOPLASMIC MEMBRANE

Phage T5 requires 0.1 mM calcium to produce phage progeny in Escherich ia coli cells, Decreasing calcium below 0.1 mM at time phage DNA was t ransferred depleted the bacteria of K+, caused membrane depolarization , perturbation of phage DNA transfer and resulted in a low internal AT P level, Our data suggest that calcium controls the conformation of th e channel involved in the transfer of phage DNA through the host envel ope and that below 0.1 mM calcium the channel remains open. This creat es an energetic state of the host unfavorable to the synthesis of phag e components and leads to abortion of the infectious process.