1qbe
From Proteopedia
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'''BACTERIOPHAGE Q BETA CAPSID''' | '''BACTERIOPHAGE Q BETA CAPSID''' | ||
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[[Category: Golmohammadi, R.]] | [[Category: Golmohammadi, R.]] | ||
[[Category: Liljas, L.]] | [[Category: Liljas, L.]] | ||
| - | [[Category: | + | [[Category: Coat protein]] |
| - | [[Category: | + | [[Category: Icosahedral virus]] |
| - | [[Category: | + | [[Category: Rna binding]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:05:44 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 03:05, 3 May 2008
BACTERIOPHAGE Q BETA CAPSID
Overview
BACKGROUND: The capsid protein subunits of small RNA bacteriophages form a T = 3 particle upon assembly and RNA encapsidation. Dimers of the capsid protein repress translation of the replicase gene product by binding to the ribosome binding site and this interaction is believed to initiate RNA encapsidation. We have determined the crystal structure of phage Q beta with the aim of clarifying which factors are the most important for particle assembly and RNA interaction in the small phages. RESULTS: The crystal structure of bacteriophage Q beta determined at 3.5 A resolution shows that the capsid is stabilized by disulfide bonds on each side of the flexible loops that are situated around the fivefold and quasi-sixfold axes. As in other small RNA phages, the protein capsid is constructed from subunits which associate into dimers. A contiguous ten-stranded antiparallel beta sheet facing the RNA is formed in the dimer. The disulfide bonds lock the constituent dimers of the capsid covalently in the T = 3 lattice. CONCLUSIONS: The unusual stability of the Q beta particle is due to the tight dimer interactions and the disulfide bonds linking each dimer covalently to the rest of the capsid. A comparison with the structure of the related phage MS2 shows that although the fold of the Q beta coat protein is very similar, the details of the protein-protein interactions are completely different. The most conserved region of the protein is at the surface, which, in MS2, is involved in RNA binding.
About this Structure
1QBE is a Single protein structure of sequence from Enterobacteria phage qbeta. Full crystallographic information is available from OCA.
Reference
The crystal structure of bacteriophage Q beta at 3.5 A resolution., Golmohammadi R, Fridborg K, Bundule M, Valegard K, Liljas L, Structure. 1996 May 15;4(5):543-54. PMID:8736553 Page seeded by OCA on Sat May 3 06:05:44 2008
