3QC7

The structure of bacteriophage phi29 head fibers has a supercoiled triple repeating helix-turn-helix motif

Summary for 3QC7

• Entry DOI: 10.2210/pdb3qc7/pdb
• Descriptor: Head fiber protein (2 entities in total)
• Functional Keywords: supercoiled triple repeating helix-turn-helix, viral protein
• Biological source: Bacillus phage phi29 (Bacteriophage phi-29)
• Total number of polymer chains: 1
• Total formula weight: 18923.36

Authors

Xiang, Y.,Rossmann, M.G. (deposition date: 2011-01-15, release date: 2011-01-26, Last modification date: 2024-02-21)

Primary citation

Xiang, Y.,Rossmann, M.G.
Structure of bacteriophage {phi}29 head fibers has a supercoiled triple repeating helix-turn-helix motif.
Proc.Natl.Acad.Sci.USA, 108:4806-4810, 2011

PubMed Abstract: The tailed bacteriophage 29 capsid is decorated with 55 fibers attached to quasi-3-fold symmetry positions. Each fiber is a homotrimer of gene product 8.5 (gp8.5) and consists of two major structural parts, a pseudohexagonal base and a protruding fibrous portion that is about 110 Å in length. The crystal structure of the C-terminal fibrous portion (residues 112-280) has been determined to a resolution of 1.6 Å. The structure is about 150 Å long and shows three distinct structural domains designated as head, neck, and stem. The stem region is a unique three-stranded helix-turn-helix supercoil that has not previously been described. When fitted into a cryoelectron microscope reconstruction of the virus, the head structure corresponded to a disconnected density at the distal end of the fiber and the neck structure was located in weak density connecting it to the fiber. Thin section studies of Bacillus subtilis cells infected with fibered or fiberless 29 suggest that the fibers might enhance the attachment of the virions onto the host cell wall.

PubMed: 21383126
DOI: 10.1073/pnas.1018097108

Experimental method

X-RAY DIFFRACTION (1.52 Å)