Determination of the packaging capacity of bacteriophage VWB.

VWB is a temperate bacteriophage whose chromosome has cohesive ends. VWB can stably package modified chromosomes that contain insertions of up to about 4 kilobases of foreign DNA. Phage particles containing extra DNA differ from the wild type in their increased sensitivity to chelating agents. Because of these properties, VWB is a promising cloning vector for Streptomyces venezuelae.