Antigenic properties of bacteriophage phi 29 structural proteins

Abstract

Serological methods and electron microscopy were used to study the structural proteins of the small Bacillus subtilis bacteriophage phi29. This virus has a large number of fibers attached at both ends of its prolate head. A complex neck assembly is comprised of 12 symmetrically arranged appendages as the outer component. Head fibers, neck appendages, and the head surface bind anti-phi29 antibodies. Immune sera absorbed with defective lysates of suppressor-sensitive (sus) mutants have been used to determine the genetic control of neck appendages production. Studies on the serum-blocking power of lysates defective in different tail components showed that appendages contain the main serum-blocking protein. This finding suggests an essential role of the neck appendages in phage adsorption or DNA injection.