Atomic structure reveals the unique capsid organization of a dsRNA virus.
For most dsRNA viruses, the genome-enclosing capsid comprises 120 copies of a single capsid protein (CP) organized into 60 icosahedrally equivalent dimers, generally identified as 2 nonsymmetricallyinteracting CP molecules with extensive lateral contacts. The crystal structure of a partitivirus, Penicillium stoloniferum virus F (PsV-F), reveals a different organization, in which the CP dimer is related by almost-perfect local 2-fold symmetry, forms prominent surface arches, and includes extensive structure swapping between the 2 subunits. An electron cryomicroscopy map of PsV-F shows that the disordered N terminus of each CP molecule interacts with the dsRNA genome and probably participates in its packaging or transcription. Intact PsV-F particles mediate semiconservative transcription, and transcripts are likely to exit through negatively charged channels at the icosahedral 5-fold axes. Other findings suggest that the PsV-F capsid is assembled from dimers of CP dimers, with an arrangement similar to flavivirus E glycoproteins.
Pan
Junhua
J
Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA.
Dong
Liping
L
Lin
Li
L
Ochoa
Wendy F
WF
Sinkovits
Robert S
RS
Havens
Wendy M
WM
Nibert
Max L
ML
Baker
Timothy S
TS
Ghabrial
Said A
SA
Tao
Yizhi Jane
YJ
D002213:Capsid / Q000737:chemistry*; D036022:Capsid Proteins / Q000737:chemistry; D020285:Cryoelectron Microscopy; D003460:Crystallization; D008954:Models, Biological; D012328:RNA Viruses / Q000737:chemistry* / Q000235:genetics; D012330:RNA, Double-Stranded; D016601:RNA-Binding Proteins; D014158:Transcription, Genetic
D036022:Capsid Proteins; D012330:RNA, Double-Stranded; D016601:RNA-Binding Proteins