Bacteriophage T4 long tail fiber domains

Abstract

Bacteriophage T4 initially recognizes its host cells using its long tail fibers. Long tail fibers consist of a phage-proximal and a phage-distal rod, each around 80 nm long and attached to each other at a slight angle. The phage-proximal rod is formed by a homo-trimer of gene product 34 (gp34) and is attached to the phage-distal rod by a monomer of gp35. The phage-distal rod consists of two protein trimers: a trimer of gp36, attached to gp35, although most of the phage-distal rod, including the receptorbinding domain, is formed by a trimer of gp37. In this review, we discuss what is known about the detailed structure and function of the different long tail fiber domains. Partial crystal structures of gp34 and gp37 have revealed the presence of new protein folds, some of which are present in several repeats, while others are apparently unique. Gp38, a phage chaperone protein necessary for folding of gp37, is thought to act on an α-helical coiled-coil region in gp37. Future studies should reveal the remaining structure of the long tail fibers, how they assemble into a functional unit, and how the long tail fibers trigger the infection process after successful recognition of a suitable host bacterium.

Morphologically Different Pectobacterium brasiliense Bacteriophages PP99 and PP101: Deacetylation of O-Polysaccharide by the Tail Spike Protein of Phage PP99 Accompanies the Infection

“…Three proteins are predicted to form tail fibers of PP101, and these proteins have orthologs in other phages of the group (Table 1). We suggest the presence of the multicomponent tail fibers resembling those of phage T4 (Hyman and van Raaij, 2018) in PP101. PP101 ORF 77 and ORF78 have a high degree of identity with corresponding ORFs of PM1/ST32/phiEcoM-GJ1/vB_EamM-Y2/Faunus, presumably forming the proximal part of the fiber and the knee-knob.…”

Phage S144, a New Polyvalent Phage Infecting Salmonella spp. and Cronobacter sakazakii

“…Some variation of the O-antigen receptor is tolerated by some phages, such as the podovirus HK620 that cleaves the O-antigen of E. coli belonging to serogroup O18A both in the absence or presence of a branching glucose [62]. However, further experiments are needed to determine if O-antigen is the only receptor needed for S144 to eject its DNA in S. Muenster and C. sakazakii, as seen for phages HK620 and P22 [62,63], or if a secondary receptor is required for infection, as reported for phage T4 [64].…”

Comparative Genomics of Two New HF1-like Haloviruses

“…Viruses of the HF1-group are closely related but vary widely in their host specificity ( Table 2, and Figure 4, right side), which should be reflected in the receptor binding proteins (RBPs) they use for attachment to their cognate host species. In caudoviruses, these are usually tail proteins that carry receptor binding domains (RBDs) [35]. Comparison of the HF1 and HF2 genomes indicated that one of two major divergent regions (MDR) carried the RBP.…”