T H E Protein Coats or "ghosts" of Coli Phage T2 Ii. the Biological Func~ons* by Roger M. Herriott and James L. Barlow$,§

Phage coats or ghosts, composed entirely of protein, appear to be responsible for protecting the phage nucleic acid from degradation by factors in the surrounding medium; attachment of the virus to its susceptible host; and delivering the nucleic acid to the interior of the cell. In addition, the ghosts have a number of biological actions which resemble similar actions of the patent phage. Thus, they both "kill" cells, inhibit pentosenucleic acid formation, interfere with subsequent infection by other virus particles, block adaptive enzyme formation, induce or trigger lysis of the host, and cause a leakage of phosphorus-containing fragments from the cell. Results to date fail to demonstrate a direct involvement of the ghosts in the passage of genetic information to the progeny. Several of the above changes induced in the host cell following attachment of ghosts could be derived from an alteration in but a single metabolic reaction. The stoichiometry of the ghost-bacterial cell interaction is different from that of the parent phage. Experiments to distinguish between a variable response of the host cell to reaction at different sites and a state of heterogeneity in the ghost preparations suggest the former but they ate not decisive. I t was reported earlier (1) that certain biological properties of intact T2 phage were also found in its coat or ghost freed of the nucleic acid. The present article describes in some detail the experiments and results involved in an extension of that report. I t will be shown that the phage properties of (a) host range specificity, (b) "killing" action, (c) inhibition of host PNA synthesis, (d) interference, (e) induction of lysis in the host cells, and (~) induced leakage of host phosphorus-containing fragments are also properties of the proteinous coat or "ghost." No genetic activity was detectable in the ghosts. These findings point to a * Aided by a grant from the National Foundation for Infantile Paralysis. :~ Supported in part by a grant from the United States Atomic Energy Commission to R. M. H. §Present address: Laboratory of Protein Chemistry, Division of Laboratories and Research, New York State Department of Health, Albany.