Comment in:
Cytoplasmic polyhedrosis virus structure at 8 A by electron cryomicroscopy: structural basis of capsid stability and mRNA processing regulation.
Zhou ZH, Zhang H, Jakana J, Lu XY, Zhang JQ.
Department of Pathology and Laboratory Medicine, University of Texas Medical School, Houston, TX 77030, USA. z.h.zhou@uth.tmc.edu
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.
Publication Types:
PMID: 12791254 [PubMed - indexed for MEDLINE]