Release of O antigen polysaccharide from Salmonella newington by phage epsilon 34.

Phage ?³⁴ cleaves its own receptor site on the cell surface of its host bacterium, Salmonella newington. The receptor is an O antigen polysaccharide consisting of mannosyl-rhamnosyl-galactose repeating units joined together by β-galactosyl linkages. A series of polysaccharides produced by this cleavage contains mannose, rhamnose and galactose. The identified end-groups generated by this cleavage are galactose, indicating the cleavage is caused by the specific breakage of β-galactosyl 1–6 mannose linkages.A soluble protein found in ?³⁴-infected cells also cleaves the O antigen, liberating polyand oligosaccharide fragments. The protein was identified as the base plate parts of this phage by morphological hybrid formation with phage P22 head particles. From the results obtained we conclude that each base plate part of this phage is a kind of endogalactosidase, which specifically acts on the O antigen of S. newington. The phage or its base plate parts cleave the O antigen of S. anatum or that of S. minneapolis poorly or not at all.Free base plate parts were also found in lysate of c341-infected cells. In this case, however, no cleavage of O antigen polysaccharide was detected using either phage particles or the isolated base plate parts.