1YC6

Crystallographic Structure of the T=1 Particle of Brome Mosaic Virus

Summary for 1YC6

• Entry DOI: 10.2210/pdb1yc6/pdb
• Related: 1js9
• Descriptor: Coat protein (2 entities in total)
• Functional Keywords: structural transition, proteolysis, bmv, almv, symmetry, assembly, icosahedral virus, virus
• Biological source: Brome mosaic virus
• Cellular location: Virion (Potential): P03602
• Total number of polymer chains: 30
• Total formula weight: 494036.88

Authors

Larson, S.B.,Lucas, R.W.,McPherson, A. (deposition date: 2004-12-22, release date: 2005-01-18, Last modification date: 2023-08-23)

Primary citation

Larson, S.B.,Lucas, R.W.,McPherson, A.
Crystallographic structure of the T=1 particle of brome mosaic virus.
J.Mol.Biol., 346:815-831, 2005

PubMed Abstract: T=1 icosahedral particles of amino terminally truncated brome mosaic virus (BMV) protein were created by treatment of the wild-type T=3 virus with 1M CaCl2 and crystallized from sodium malonate. Diffraction data were collected from frozen crystals to beyond 2.9 A resolution and the structure determined by molecular replacement and phase extension. The particles are composed of pentameric capsomeres from the wild-type virions which have reoriented with respect to the original particle pentameric axes by rotations of 37 degrees , and formed tenuous interactions with one another, principally through conformationally altered C-terminal polypeptides. Otherwise, the pentamers are virtually superimposable upon those of the original T=3 BMV particles. The T=1 particles, in the crystals, are not perfect icosahedra, but deviate slightly from exact symmetry, possibly due to packing interactions. This suggests that the T=1 particles are deformable, which is consistent with the loose arrangement of pentamers and latticework of holes that penetrate the surface. Atomic force microscopy showed that the T=3 to T=1 transition could occur by shedding of hexameric capsomeres and restructuring of remaining pentamers accompanied by direct condensation. Knowledge of the structures of the BMV wild-type and T=1 particles now permit us to propose a tentative model for that process. A comparison of the BMV T=1 particles was made with the reassembled T=1 particles produced from the coat protein of trypsin treated alfalfa mosaic virus (AlMV), another bromovirus. There is little resemblance between the two particles. The BMV particle, with a maximum diameter of 195 A, is made from distinctive pentameric capsomeres with large holes along the 3-fold axis, while the AlMV particle, of approximate maximum diameter 220 A, has subunits closely packed around the 3-fold axis, large holes along the 5-fold axis, and few contacts within pentamers. In both particles crucial linkages are made about icosahedral dyads.

PubMed: 15713465
DOI: 10.1016/j.jmb.2004.12.015

Experimental method

X-RAY DIFFRACTION (2.9 Å)