Related Experiment Video

Updated: Jul 11, 2026

Phage Therapy Application to Counteract Pseudomonas aeruginosa Infection in Cystic Fibrosis Zebrafish Embryos
11:20

Phage Therapy Application to Counteract Pseudomonas aeruginosa Infection in Cystic Fibrosis Zebrafish Embryos

Published on: May 12, 2020

Cryo-EM study of the Pseudomonas bacteriophage phiKZ

Andrei Fokine1, Anthony J Battisti, Valorie D Bowman

  • 1Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA.

Structure (London, England : 1993)
|September 14, 2007
PubMed

Insights

The phiKZ virus, a large bacteriophage infecting Pseudomonas aeruginosa, has a unique tail structure. Its tail sheath proteins, though lacking sequence similarity to T4 phage, suggest a shared evolutionary origin.

Area of Science:

  • Structural virology
  • Bacteriophage research
  • Microbial pathogenesis

Background:

  • The phiKZ virus is a large bacteriophage that infects Pseudomonas aeruginosa, a bacterium often pathogenic to humans.
  • Bacteriophages, including phiKZ, are viruses that infect bacteria and hold potential for phage therapy applications.
  • Understanding the structure of bacteriophage virions is crucial for elucidating their infection mechanisms and therapeutic potential.

Purpose of the Study:

  • To determine the three-dimensional structure of the phiKZ bacteriophage tail using cryo-electron microscopy.
  • To compare the structural features of the phiKZ tail with that of other well-characterized bacteriophages, such as T4.
  • To investigate potential evolutionary relationships between phiKZ and other bacteriophages based on structural similarities.

Main Methods:

  • Cryo-electron microscopy (cryo-EM) was employed to visualize the intricate structure of the phiKZ virion.
  • Image processing and 3D reconstruction techniques were used to generate high-resolution structural models of the phiKZ tail.
  • Comparative structural analysis was performed between the phiKZ tail and the T4 bacteriophage tail.

Main Results:

  • The phiKZ virion possesses an icosahedral head (approx. 1450 Å diameter) and a long contractile tail (approx. 2000 Å length).
  • The phiKZ tail sheath shares comparable helical parameters with bacteriophage T4, despite a lack of sequence similarity in their proteins.
  • The phiKZ baseplate is larger and flatter than T4's but also features a cell-puncturing device.

Conclusions:

  • The structural similarities in the contractile sheaths suggest a common evolutionary ancestor between phiKZ and T4 bacteriophages.
  • The distinct baseplate structure of phiKZ, including its cell-puncturing device, highlights unique adaptations for host cell infection.
  • Detailed structural insights into phiKZ advance our understanding of bacteriophage diversity and their potential in therapeutic strategies.

More Related Videos

Bacteriophage Effectiveness for Biocontrol of Foodborne Pathogens Evaluated via High-Throughput Settings07:22

Bacteriophage Effectiveness for Biocontrol of Foodborne Pathogens Evaluated via High-Throughput Settings

Published on: August 19, 2021

T4 Bacteriophage and E. coli Interaction in the Murine Intestine: A Prototypical Model for Studying Host-Bacteriophage Dynamics In Vivo08:46

T4 Bacteriophage and E. coli Interaction in the Murine Intestine: A Prototypical Model for Studying Host-Bacteriophage Dynamics In Vivo

Published on: January 26, 2024

Related Concept Videos

DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
Lytic Cycle of Bacteriophages01:30

Lytic Cycle of Bacteriophages

Bacteriophages, also known as phages, are specialized viruses that infect bacteria. A key characteristic of phages is their distinctive “head-tail” morphology. A phage begins the infection process (i.e., lytic cycle) by attaching to the outside of a bacterial cell. Attachment is accomplished via proteins in the phage tail that bind to specific receptor proteins on the outer surface of the bacterium. The tail injects the phage’s DNA genome into the bacterial cytoplasm. In the lytic replication...
Cryo-electron Microscopy01:28

Cryo-electron Microscopy

Conventional electron microscopy (EM) involves dehydration, fixation, and staining of biological samples, which distorts the native state of biological molecules and results in several artifacts. Also, the high-energy electron beam damages the sample and makes it difficult to obtain high-resolution images. These issues can be addressed using cryo-EM, which uses frozen samples and gentler electron beams. The technique was developed by Jacques Dubochet, Joachim Frank, and Richard Henderson, for...
Lysogenic Cycle of Bacteriophages00:43

Lysogenic Cycle of Bacteriophages

In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...