title: Cryo-electron tomography of vaccinia virus.
abstract: The combination of cryo-microscopy and electron tomographic reconstruction has allowed us to determine the structure of one of the more complex viruses, intracellular mature vaccinia virus, at a resolution of 4-6 nm. The tomographic reconstruction allows us to dissect the different structural components of the viral particle, avoiding projection artifacts derived from previous microscopic observations. A surface-rendering representation revealed brick-shaped viral particles with slightly rounded edges and dimensions of approximately 360 x 270 x 250 nm. The outer layer was consistent with a lipid membrane (5-6 nm thick), below which usually two lateral bodies were found, built up by a heterogeneous material without apparent ordering or repetitive features. The internal core presented an inner cavity with electron dense coils of presumptive DNA-protein complexes, together with areas of very low density. The core was surrounded by two layers comprising an overall thickness of approximately 18-19 nm; the inner layer was consistent with a lipid membrane. The outer layer was discontinuous, formed by a periodic palisade built by the side interaction of T-shaped protein spikes that were anchored in the lower membrane and were arranged into small hexagonal crystallites. It was possible to detect a few pore-like structures that communicated the inner side of the core with the region outside the layer built by the T-shaped spike palisade.
authors.affiliation: Max Planck Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried, Germany.
authors.forename: Marek
authors.initials: M
authors.lastname: Cyrklaff
authors.forename: Cristina
authors.initials: C
authors.lastname: Risco
authors.forename: Jose Jesús
authors.initials: JJ
authors.lastname: Fernández
authors.forename: Maria Victoria
authors.initials: MV
authors.lastname: Jiménez
authors.forename: Mariano
authors.initials: M
authors.lastname: Estéban
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Baumeister
authors.forename: José L
authors.initials: JL
authors.lastname: Carrascosa
mesh_terms: D020285:Cryoelectron Microscopy; D014054:Tomography; D014616:Vaccinia virus / Q000648:ultrastructure*