Effects of the cowpea chlorotic mottle bromovirus beta-hexamer structure on virion assembly.
The X-ray crystal structure of Cowpea chlorotic mottle bromovirus (CCMV) revealed a unique tubular structure formed by the interaction of the N-termini from six coat protein subunits at each three-fold axis of the assembled virion. This structure, termed the beta-hexamer, consists of six short beta-strands. The beta-hexamer was postulated to play a critical role in the assembly and stability of the virion by stabilizing hexameric capsomers. Mutational analyses of the beta-hexamer structure, utilizing both in vitro and in vivo assembly assays, demonstrate that this structure is not required for virion formation devoid of nucleic acids in vitro or for RNA-containing virions in vivo. However, the beta-hexamer structure does contribute to virion stability in vitro and modulates disease expression in vivo. These results support a model for CCMV assembly through pentamer intermediates.
Willits
D
D
Department of Plant Sciences Plant Pathology, Montana State University, Bozeman, MT 59717, USA.
Zhao
X
X
Olson
N
N
Baker
T S
TS
Zlotnick
A
A
Johnson
J E
JE
Douglas
T
T
Young
M J
MJ
D001483:Base Sequence; D017795:Bromovirus / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D036022:Capsid Proteins / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D004279:DNA, Viral / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D007887:Fabaceae / Q000821:virology; D007091:Image Processing, Computer-Assisted; D008958:Models, Molecular; D010935:Plant Diseases / Q000821:virology; D017433:Protein Structure, Secondary; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure; D017384:Sequence Deletion
D036022:Capsid Proteins; D004279:DNA, Viral; D021122:Protein Subunits; D011994:Recombinant Proteins