Pathway of PHIX174 Protein E Mediated Lysis of Escherichia coli

Abstract

Genetic analysis of phage PhiX174 mutants (Hutchison and Sinsheimer 1966) identified a single lysis gene of the phage, E, and it was shown that its expression from a plasmid is sufficient to cause bacterial lysis (Henrich et al., 1982; Young and Young, 1982). A summary of specific features of protein E-mediated lysis is given in table 1. Gene E codes for a membrane protein of 91 amino acids (Barrell et al., 1976) detectable in the inner and outer membrane fractions of E. coli (Bläsi et al., 1983; Altman et al., 1985; Bläsi et al., 1989). It exerts its lytic effect by a process which is dependent on the proton-motive-force of the cells (Witte et al., 1987) and on cellular factors which are coupled with the growth phase of the cells as well as with the regulation of the cells autolytic system (Lubitz et al., 1984a, b). E-lysed cells show discrete holes in their cell envelopes which are preferentialy located in potential division zones of the cells (Witte et al., 1990a). Questions which remain to be answered are concerned with the molecular architecture of the E-specific lysis tunnel, its dependence on cellular proteins and on indirect effects of local membrane disturbance.