Host receptor site for the short tail fibers of bacteriophage T4D

Abstract

The composition and structure of the Escherichia coli B receptor for the short tail fibers on the baseplate of bacteriophage T4D has been partially characterized. Incubation of a partially purified preparation containing T4D short tail fibers with purified host cell lipopolysaccharide (LPS) resulted in the formation of a complex which was readily sedimented by centrifugation at 9000 g. The protein involved in the formation of this complex has been identified as the protein which makes up the T4D short tail fibers. Additional evidence for the binding of short tail fibers to purified LPS was obtained by mixing LPS vesicles with purified tail substructures of T4D. Vesicles were observed surrounding the distal end of about 10% of the tail substructures observed in electron micrographs. Short tail fibers could be seen extending from these tail substructures attached to the LPS. The tail substructures which had interacted with LPS all had contracted sheaths. Interaction between isolated short tail fibers and LPS-containing particles which had detached from the cell walls of E. coli B grown in media of high osmolarity was also observed in electron micrographs.