title: Crystallographic structure of the alpha-helical triple coiled-coil domain of avian reovirus S1133 fibre.
abstract: Avian reovirus fibre, a homo-trimer of the sigmaC protein, is a minor component of the avian reovirus outer capsid. It is anchored via a short N-terminal sequence to the inner capsid lambdaC pentamer, and its protruding globular C-terminal domain is responsible for primary host cell attachment. We have previously solved the structure of a receptor-binding fragment in which residues 160-191 form a triple beta-spiral and 196-326 a beta-barrel head domain. Here we have expressed, purified and crystallized a major sigmaC fragment comprising residues 117-326. Its structure, which was solved by molecular replacement using the previously determined receptor-binding domain structure and refined to 1.75 A (0.175 nm) resolution, reveals an alpha-helical triple coiled-coil connected to the previously solved structure by a zinc-ion-containing linker. The coiled-coil domain contains two chloride ion binding sites, as well as specific trimerization and registration sequences. The linker may act as a functionally important hinge.
authors.affiliation: Departamento de Bioquímica e Bioloxía Molecular, Facultade de Farmacia, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Guardado-Calvo
authors.affiliation: Spanish CRG beamline BM16, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France.
authors.forename: Gavin C
authors.initials: GC
authors.lastname: Fox
authors.affiliation: Unidade de Raios X, Laboratorio Integral de Dinámica e Estructura de Biomoléculas José R. Carracido, Edificio CACTUS, Campus Sur, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Antonio L
authors.initials: AL
authors.lastname: Llamas-Saiz
authors.affiliation: Instituto de Biología Molecular de Barcelona-CSIC, c/Josep-Samitier 1-5, E-08028 Barcelona, Spain.|Departamento de Bioquímica e Bioloxía Molecular, Facultade de Farmacia, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: van Raaij
mesh_terms: D000818:Animals; D002213:Capsid / Q000737:chemistry*; D036022:Capsid Proteins / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods*; D008958:Models, Molecular; D030101:Orthoreovirus, Avian / Q000737:chemistry*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
chemical_list: D036022:Capsid Proteins