title: Pleomorphic configuration of the trimeric capsid proteins of Rice dwarf virus that allows formation of both the outer capsid and tubular crystals.
abstract: In the double-shelled capsid of Phytoreovirus, the outer capsid attaches firmly to the 3-fold axes of the T=1 core. It then forms a T=13 lattice via lateral interactions among the P8 trimers (Wu et al., 2000, Virology 271, 18-25). Purified P8 molecules also assemble into hexagonal monolayers as well as tubular crystals. To explore the mechanisms of formation of these structures, the configurations of P8 trimers were compared and verified in particles of Rice dwarf virus and in tubular crystals (tubes) whose structure was determined by cryoelectron microscopy using helical reconstruction technique. Remarkable variations in intertrimer contacts were observed in the tubes and in the surface lattice of Rice dwarf virus capsid. Superposition of the atomic structure of P8 trimers in the structures analyzed by cryoelectron microscopy allowed us to identify groups of specific and stable interactions, some of which were preserved in the tubes and the quasi-equivalent T=13 icosahedral lattice of the virion's shell. The flexible nature of the binding between P8 trimers, created via electrostatic interactions that hold radially inward, appears to allow the outer-capsid P8 trimers to envelop the ragged surface of the core, forming the double shell of an intact viral particle.
authors.affiliation: Department of Biophysical Engineering, Faculty of Engineering Science, Osaka University, Toyonaka 560-0043, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Iwasaki
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Miyazaki
authors.forename: Lena
authors.initials: L
authors.lastname: Hammar
authors.forename: Yafeng
authors.initials: Y
authors.lastname: Zhu
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Omura
authors.forename: Bomu
authors.initials: B
authors.lastname: Wu
authors.forename: Fredrik
authors.initials: F
authors.lastname: Sjöborg
authors.forename: Koji
authors.initials: K
authors.lastname: Yonekura
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Murata
authors.forename: Keiichi
authors.initials: K
authors.lastname: Namba
authors.forename: Donald L
authors.initials: DL
authors.lastname: Caspar
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujiyoshi
authors.forename: R Holland
authors.initials: RH
authors.lastname: Cheng