DNA packaging and developmental intermediates of a broad host range Vibrio vulnificus bacteriophage 71A-6

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S A Khan1, A A Khan, M S Nawaz

  • 1Division of Microbiology, National Center for Toxicological Research, Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079, USA.

Molecular and Cellular Probes
|April 9, 2001
PubMed

Insights

Structural intermediates of Vibrio vulnificus bacteriophage 71A-6 were studied. Key proteins involved in capsid assembly and DNA packaging were identified, revealing insights into podovirus replication.

Area of Science:

  • Virology
  • Molecular Biology
  • Structural Biology

Background:

  • Bacteriophages are viruses that infect bacteria and are crucial in microbial ecosystems.
  • Understanding bacteriophage assembly and DNA packaging is vital for phage therapy and genetic engineering.
  • Vibrio vulnificus bacteriophage 71A-6 is a double-stranded DNA podovirus with a rod-shaped morphology.

Purpose of the Study:

  • To investigate the structural intermediates in the capsid assembly and DNA packaging pathway of Vibrio vulnificus bacteriophage 71A-6.
  • To identify key phage and host proteins involved in these processes.
  • To characterize the morphological changes during DNA packaging.

Main Methods:

  • Isolation of structural intermediates via ultracentrifugation.
  • Analysis using electron microscopy, SDS-PAGE, and pulsed-field gel electrophoresis.
  • Determination of genome size and protein composition.

Main Results:

  • Rod-shaped capsids (200 nm length) were synthesized during phage development.
  • Capsid dimensions changed (220 nm length) during or after DNA packaging.
  • A capsid-DNA complex including a 42.5-kDa protein was isolated; 12 phage and 8 host proteins were identified.
  • A 143.0-kb genome was determined, with mature phage proteins comprising only 14.0% of coding capacity.

Conclusions:

  • The study elucidated key structural intermediates and protein players in Vibrio vulnificus bacteriophage 71A-6 assembly and DNA packaging.
  • Morphological changes in capsids correlate with DNA packaging.
  • Identified proteins, including a major capsid protein and a packaging initiator/terminator, are critical for the phage life cycle.

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