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The bacteriophage T4 DNA injection machine.

Michael G Rossmann1, Vadim V Mesyanzhinov, Fumio Arisaka

  • 1Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907-2054, USA. mgr@indiana.bio.purdue.edu

Current Opinion in Structural Biology
|April 20, 2004
PubMed
Summary
This summary is machine-generated.

Bacteriophage T4 tail fibers initiate DNA injection by triggering baseplate conformational changes. This structural switch activates sheath contraction and DNA transfer into host cells, aided by a lysozyme-based membrane-puncturing device.

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Area of Science:

  • Molecular biology
  • Virology
  • Structural biology

Background:

  • Bacteriophage T4 is a virus that infects bacteria.
  • Its tail structure is crucial for DNA injection into host cells.
  • The tail comprises a contractile sheath, rigid tube, and a baseplate with tail fibers.

Purpose of the Study:

  • To elucidate the structural and functional roles of the bacteriophage T4 tail.
  • To understand the mechanism of sheath contraction and DNA transfer initiation.
  • To investigate the function of the baseplate and its associated components.

Main Methods:

  • Structural analysis of the bacteriophage T4 tail components.
  • Biochemical assays to study protein interactions and conformational changes.
  • Infectivity assays to assess the role of tail structures in DNA injection.

Main Results:

  • The baseplate undergoes a significant conformational switch upon tail fiber binding to cell receptors.
  • This switch triggers the contraction of the sheath, facilitating DNA ejection.
  • A central membrane-puncturing device, featuring lysozyme domains, disrupts the bacterial cell envelope.

Conclusions:

  • The bacteriophage T4 tail is a sophisticated molecular machine for DNA delivery.
  • Baseplate conformational changes are key to initiating the infection process.
  • The lysozyme domains are essential for penetrating the bacterial cell wall.