Outer surface protein of bacteriophage lambda

Abstract

The bacteriophage λ capsid is composed of a main shell protein (pE) and an outer surface protein (pD). The outer surface protein was purified from sources of free protein and assembled protein. The amino acid composition, C- and N-terminals, iso-electric point, molecular weight, and state of aggregation were determined. In vitro the outer surface protein binds specifically to structures composed of λ main shell protein in the expanded configuration i.e. to enlarged preheads, pD-deficient bacteriophage particles, and polyheads. We discuss the binding of pD to the shell surface as a "pseudo-crystallisation process", its clustering on the surface as trimers and its role as stabiliser of the filled head. © 1980.