Receptor specificity of the short tail fibres (gp12) of T-even type Escherichia coli phages

Abstract

Short tail fibres of T-even like phages are involved in host recognition. To determine the specificity of the fibres, the region containing gene 12 of phages T2, K3, and K3hx was cloned. The genes 11, 12, wac, and 13, coding for the baseplate outer wedge, short tail fibres, collar wishes, and a head completion component, respectively, were localized on the cloned fragments. Plasmid-encoded gene 12 could be expressed without helper phage. Efficient expression of gene 12 from T2 and K3hx made an extraction of protein 12 possible. Hybrid phages obtained by in vitro complementation, recombination analysis and protein 12 binding to host range mutant bacteria excluded a role of the short tail fibres from T2, K3 or K3hx in the recognition of outer membrane proteins. Binding patterns of protein 12 to different Escherichia coli lipopolysaccharide mutants and inhibition of binding of protein 12 by a monoclonal antibody against the core region of E. coli K12 lipopolysaccharide suggested that heptose residues are necessary for efficient binding. The binding site of the same monoclonal antibody is different from the short tail fibre binding site in an E. coli B strain suggesting different binding specificities of protein 12. Thus, the ability of different bacterial strains to inactivate phage could be related to differences in the binding specificity of the short tail fibres for the lipopolysaccharides of these bacteria.

Crystallization of the carboxy-terminal region of the bacteriophage T4 proximal long tail fibre protein gp34

“…The long tail fibres recognize the outer membrane protein C (OmpC) protein or lipopolysaccharide (LPS) of Escherichia coli and are responsible for the initial and reversible attachment of the virion. After at least three long tail fibres have bound, the baseplate changes conformation and the short tail fibres extend and bind irreversibly to the host-cell LPS (Riede, 1987). The short tail fibres serve as inextensible stays during contraction of the tail sheath and penetration of the cell envelope by the tail tube (Kanamaru et al, 2002).…”

Structure of the bacteriophage T4 long tail fiber receptor-binding tip

“…1). Upon receptor binding, a recognition signal is sent to the baseplate (8)(9)(10)(11), causing the short tail fibers to extend and irreversibly bind to the outer core region of the lipopolysaccharides (12). This binding is followed by contraction of the outer tail sheath (13,14), penetration of the bacterial membrane by the hollow inner tail tube (Fig.…”

Structure of the Three N-Terminal Immunoglobulin Domains of the Highly Immunogenic Outer Capsid Protein from a T4-Like Bacteriophage

“…The T4 virus initiates infection of a host cell by reversible binding of the LTFs to lipopolysaccharide molecules on the bacterial surface or to the outer membrane protein OmpC (50). Upon binding of the LTFs, a recognition signal is transmitted to the phage baseplate (16), causing the short tail fibers around the periphery of the baseplate to unravel and bind irreversibly to the lipopolysaccharides on the cell surface, thus securely anchoring the phage tail to the cell (36). The binding of the short tail fibers is followed by contraction of the tail sheath (3,24), penetration of the bacterial membrane by the tail tube, and ejection of the viral DNA into the bacterium (27,28,37).…”