2hi5
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Model for bacteriophage fd from cryo-EM
OverviewOverview
Many thin helical polymers, including bacterial pili and filamentous, bacteriophage, have been seen as refractory to high-resolution studies by, electron microscopy. Studies of the quaternary structure of such filaments, have depended upon techniques such as modeling or X-ray fiber diffraction, given that direct visualization of the subunit organization has not been, possible. We report the first image reconstruction of a filamentous virus, bacteriophage fd, by cryoelectron microscopy. Although these thin (, approximately 70 A in diameter) rather featureless filaments scatter, weakly, we have been able to achieve a nominal resolution of approximately, 8 A using an iterative helical reconstruction procedure. We show that two, different conformations of the virus exist, and that in both states the, subunits are packed differently than in conflicting models previously, proposed on the basis of X-ray fiber diffraction or solid-state NMR, studies. A significant fraction of the population of wild-type fd is, either disordered or in multiple conformational states, while in the, presence of the Y21M mutation, this heterogeneity is greatly reduced, consistent with previous observations. These results show that new, computational approaches to helical reconstruction can greatly extend the, ability to visualize heterogeneous protein polymers at a reasonably high, resolution.
About this StructureAbout this Structure
2HI5 is a Single protein structure of sequence from Phage phi3t. Full crystallographic information is available from OCA.
ReferenceReference
The structure of a filamentous bacteriophage., Wang YA, Yu X, Overman S, Tsuboi M, Thomas GJ Jr, Egelman EH, J Mol Biol. 2006 Aug 11;361(2):209-15. Epub 2006 Jun 30. PMID:16843489
Page seeded by OCA on Wed Nov 21 11:47:02 2007