Conformational switching by the scaffolding protein D directs the assembly of bacteriophage phiX174Morais, M.C., Fisher, M., Kanamaru, S., Przybyla, L., Burgner, J., Fane, B.A., Rossmann, M.G.
(2004) Mol Cell 15: 991-997
- PubMed: 15383287
- DOI: https://doi.org/10.1016/j.molcel.2004.08.023
- Primary Citation of Related Structures:
- PubMed Abstract:
The three-dimensional structure of bacteriophage phiX174 external scaffolding protein D, prior to its interaction with other structural proteins, has been determined to 3.3 angstroms by X-ray crystallography. The crystals belong to space group P4(1)2(1)2 with a dimer in the asymmetric unit that closely resembles asymmetric dimers observed in the phiX174 procapsid structure. Furthermore, application of the crystallographic 4(1) symmetry operation to one of these dimers generates a tetramer similar to the tetramer in the icosahedral asymmetric unit of the procapsid. These data suggest that both dimers and tetramers of the D protein are true morphogenetic intermediates and can form independently of other proteins involved in procapsid morphogenesis. The crystal structure of the D scaffolding protein thus represents the state of the polypeptide prior to procapsid assembly. Hence, comparison with the procapsid structure provides a rare opportunity to follow the conformational switching events necessary for the construction of complex macromolecular assemblies.
Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907, USA.