Branched lateral tail fiber organization in T5-like bacteriophages DT57C and DT571/2 is revealed by genetic and functional analysis

Alla K. Golomidova, Eugene E. Kulikov, Nikolai S. Prokhorov, Ricardo C. Guerrero-Ferreira, Yuriy A. Knirel, Elena S. Kostryukova, Karina K. Tarasyan, Andrey V. Letarov

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


The T5-like siphoviruses DT57C and DT571/2, isolated from horse feces, are very closely related to each other, and most of their structural proteins are also nearly identical to T5 phage. Their LTFs (L-shaped tail fibers), however, are composed of two proteins, LtfA and LtfB, instead of the single Ltf of bacteriophage T5. In silico and mutant analysis suggests a possible branched structure of DT57C and DT571/2 LTFs, where the LtfB protein is connected to the phage tail via the LtfA protein and with both proteins carrying receptor recognition domains. Such adhesin arrangement has not been previously recognized in siphoviruses. The LtfA proteins of our phages are found to recognize different host O-antigen types: E. coli O22-like for DT57C phage and E. coli O87 for DT571/2. LtfB proteins are identical in both phages and recognize another host receptor, most probably lipopolysaccharide (LPS) of E. coli O81 type. In these two bacteriophages, LTF function is essential to penetrate the shield of the host’s O-antigens. We also demonstrate that LTF-mediated adsorption becomes superfluous when the non-specific cell protection by O-antigen is missing, allowing the phages to bind directly to their common secondary receptor, the outer membrane protein BtuB. The LTF independent adsorption was also demonstrated on an O22-like host mutant missing O-antigen O-acetylation, thus showing the biological value of this O-antigen modification for cell protection against phages.

Original languageEnglish (US)
Article number26
Issue number1
StatePublished - Jan 21 2016


  • Bacteriophage
  • Bacteriophage adsorption
  • E. coli O-antigen
  • Horse feces
  • O-antigen O-acetylation
  • Phage branched adhesin
  • Phage in situ evolution
  • T5-like phage
  • Tail fiber proteins

ASJC Scopus subject areas

  • Infectious Diseases
  • Virology


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