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Structure of the bacteriophage PhiKZ non-virion RNA polymerase

Natàlia deYMartín Garrido1, Mariia Orekhova2, Yuen Ting Emilie Lai Wan Loong1

  • 1Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, UK.

Nucleic Acids Research
|June 28, 2021
PubMed

Insights

Bacteriophage PhiKZ, a virus targeting Pseudomonas aeruginosa, has a unique RNA polymerase essential for its replication. Its structure reveals a fifth subunit evolved from a sigma factor, offering insights into viral transcription mechanisms.

Area of Science:

  • Virology
  • Structural Biology
  • Molecular Biology

Background:

  • Bacteriophage PhiKZ infects Pseudomonas aeruginosa, a resistant pathogen with significant health implications.
  • PhiKZ employs unique strategies, including forming a viral nucleus and expressing its own RNA polymerases, to control host machinery.
  • Understanding PhiKZ's replication is crucial for developing phage therapy against antibiotic-resistant bacteria.

Purpose of the Study:

  • To determine the structure of the PhiKZ non-virion RNA polymerase (nvRNAP).
  • To elucidate the assembly, homology, and function of the PhiKZ nvRNAP complex.
  • To investigate the role of the essential fifth subunit within the nvRNAP.

Main Methods:

  • High-resolution (better than 3.0 Å) structural determination of the PhiKZ nvRNAP.
  • Bioinformatic analysis to assess subunit homology.
  • Biochemical assays to probe the function of the fifth subunit.

Main Results:

  • The structure of PhiKZ nvRNAP was resolved, revealing its multi-subunit composition.
  • The fifth subunit was identified as an integral component of the nvRNAP complex.
  • Structural and biochemical data suggest the fifth subunit evolved from an ancestral sigma factor homologue.

Conclusions:

  • The structure of PhiKZ nvRNAP provides critical insights into its assembly and function.
  • The fifth subunit plays an essential role in viral transcription and likely evolved from a sigma factor.
  • This research deepens our understanding of bacteriophage transcription and has implications for phage therapy development.

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