Crystallographic structure of the alpha-helical triple coiled-coil domain of avian reovirus S1133 fibre.
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.
Guardado-Calvo
Pablo
P
Departamento de Bioquímica e Bioloxía Molecular, Facultade de Farmacia, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
Fox
Gavin C
GC
Spanish CRG beamline BM16, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble, France.
Llamas-Saiz
Antonio L
AL
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.
van Raaij
Mark J
MJ
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.
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
D036022:Capsid Proteins