Characterization of Vibrio eltor Typing Phages: Properties of the Eltor Phage e4

Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Calcutta 700 032, India and 1 Protein Chemistry Laboratory, Imperial Cancer Research Fund Laboratories, Lincoln's Inn Fields, London WC2A 3PX, U.K. Biophysical characteristics of Vibrio eltor phage e 4 , a key phage in the Vibrio cholerae typing scheme were studied. This icosahedral phage was found to contain 12 structural polypeptides with mol. wt. ranging from 25000 to 120000. One of these polypeptides of mol. wt. 50000 accounted for most of the structural proteins present and was probably the major phage capsid protein. The phage genome comprised a single linear, double-stranded DNA molecule, 69.2 kbp in length (45.6 x 10 6 mol. wt.) as determined by electron microscopy and restriction fragment analyses. The G + C content was 34.6%. Electron microscopy data indicated that unlike the DNAs of other cholera phages, phage e 4 DNA is not circularly permuted. Adsorption under normal conditions was biphasic with rate constants of 1.02 x 10 -9 /ml/min up to 60% adsorption and 3 x 10 -10 /ml/min thereafter. Intracellular phage multiplication was characterized by a latent period of 27 min. The burst size was approximately 100 phage particles per infected cells. Keywords: V. eltor phage e 4 , DNA characterization, structural polypeptides Received 17 September 1986; accepted 23 January 1987.