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Bacteriophage P22 tail accessory factor GP26 is a long triple-stranded coiled-coil
Dewan Andrews1, James S Butler, Jawdat Al-Bassam
1Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13078, USA.
The Journal of Biological Chemistry
|December 14, 2004
Summary
The tail accessory factor gp26 from bacteriophage P22 is a thermostable, triple-stranded coiled-coil protein. This protein likely forms the needle-like structure used by the phage to penetrate host outer membranes.
Area of Science:
- Virology
- Structural Biology
- Molecular Biology
Background:
- Bacteriophage P22 is a well-studied virus that infects Salmonella Typhimurium.
- The P22 phage tail is composed of five proteins, including tail accessory factors like gp26.
- Tail accessory factors are crucial for phage structure and function, including viral DNA stabilization.
Purpose of the Study:
- To isolate and characterize the tail accessory factor gp26 from bacteriophage P22.
- To elucidate the structure and biophysical properties of gp26.
- To propose a functional role for gp26 in the P22 phage infection mechanism.
Main Methods:
- Gene isolation and protein purification of gp26.
- Biochemical and biophysical techniques (e.g., thermal denaturation).
- Electron microscopy of purified gp26.
Main Results:
- gp26 was identified as a triple-stranded coiled-coil protein with a rod-like structure (~210 angstroms).
- gp26 exhibits high intrinsic thermostability (Tm ~85°C).
- Electron microscopy revealed a structure consistent with the needle-like fiber observed on P22 virions.
Conclusions:
- gp26 is a highly stable, trimeric coiled-coil protein essential for P22 phage structure.
- gp26 likely forms the penetrating fiber of the P22 tail apparatus.
- gp26 may function as a membrane-penetrating device for host outer membrane entry.