1yc6
From Proteopedia
|
Crystallographic Structure of the T=1 Particle of Brome Mosaic Virus
Overview
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.
About this Structure
1YC6 is a Single protein structure of sequence from Brome mosaic virus. Full crystallographic information is available from OCA.
Reference
Crystallographic structure of the T=1 particle of brome mosaic virus., Larson SB, Lucas RW, McPherson A, J Mol Biol. 2005 Feb 25;346(3):815-31. Epub 2005 Jan 12. PMID:15713465
Page seeded by OCA on Wed Nov 21 06:40:33 2007
