Cytoplasmic polyhedrosis virus structure at 8 A by electron cryomicroscopy: structural basis of capsid stability and mRNA processing regulation.
The single-shelled cytoplasmic polyhedrosis virus (CPV) is a unique member of the Reoviridae. Despite lacking protective outer shells, it exhibits striking capsid stability and is capable of endogenous RNA transcription and processing. The 8 A three-dimensional structure of CPV by electron cryomicroscopy reveals secondary structure elements present in the capsid proteins CSP, LPP, and TP, which have alpha+beta folds. The extensive nonequivalent interactions between CSP and LPP, the unique CSP protrusion domain, and the perfect inter-CSP surface complementarities may account for the enhanced capsid stability. The slanted disposition of TP functional domains and the stacking of channel constrictions suggest an iris diaphragm-like mechanism for opening/closing capsid pores and turret channels in regulating the highly coordinated steps of mRNA transcription, processing, and release.
Zhou
Z Hong
ZH
Department of Pathology and Laboratory Medicine, University of Texas Medical School, Houston, TX 77030, USA. z.h.zhou@uth.tmc.edu
Zhang
Hong
H
Jakana
Joanita
J
Lu
Xing-Ying
XY
Zhang
Jing-Qiang
JQ
D000818:Animals; D002213:Capsid / Q000737:chemistry* / Q000378:metabolism; D020285:Cryoelectron Microscopy; D008958:Models, Molecular; D011487:Protein Conformation; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D012087:Reoviridae / Q000737:chemistry* / Q000648:ultrastructure
D012333:RNA, Messenger