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Title: Structure of bacteriophage [phi]29 head fibers has a supercoiled triple repeating helix-turn-helix motif

Journal Article · · Proc. Natl. Acad. Sci. USA

The tailed bacteriophage {phi}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 {angstrom} in length. The crystal structure of the C-terminal fibrous portion (residues 112-280) has been determined to a resolution of 1.6 {angstrom}. The structure is about 150 {angstrom} 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 {phi}29 suggest that the fibers might enhance the attachment of the virions onto the host cell wall.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Organization:
National Science Foundation (NSF)
OSTI ID:
1028030
Journal Information:
Proc. Natl. Acad. Sci. USA, Vol. 108, Issue (12) ; 03, 2011; ISSN 0027-8424
Country of Publication:
United States
Language:
ENGLISH