Discovery of Three Toxic Proteins of <i>Klebsiella </i>Phage fHe-Kpn01

• Main Authors: Cindy M. Spruit, Anu Wicklund, Xing Wan, Mikael Skurnik, Maria I. Pajunen
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Viruses
• Subjects: bacteriophage; <i>Podoviridae</i>; <i>Drulisvirus</i>; hypothetical proteins of unknown function; toxic proteins; antibiotic resistance
• Online Access: https://www.mdpi.com/1999-4915/12/5/544

The lytic phage, fHe-Kpn01 was isolated from sewage water using an extended-spectrum beta-lactamase-producing strain of <i>Klebsiella pneumoniae </i>as a host. The genome is 43,329 bp in size and contains direct terminal repeats of 222 bp. The genome contains 56 predicted genes, of which proteomics analysis detected 29 different proteins in purified phage particles. Comparison of fHe-Kpn01 to other phages, both morphologically and genetically, indicated that the phage belongs to the family <i>Podoviridae </i>and genus <i>Drulisvirus.</i> Because fHe-Kpn01 is strictly lytic and does not carry any known resistance or virulence genes, it is suitable for phage therapy. It has, however, a narrow host range since it infected only three of the 72 tested <i>K. pneumoniae </i>strains, two of which were of capsule type KL62. After annotation of the predicted genes based on the similarity to genes of known function and proteomics results on the virion-associated proteins, 22 gene products remained annotated as hypothetical proteins of unknown function (HPUF). These fHe-Kpn01 HPUFs were screened for their toxicity in <i>Escherichia coli</i>. Three of the HPUFs, encoded by the genes <i>g10</i>, <i>g22,</i> and <i>g38,</i> were confirmed to be toxic.