Molecular interactions and viral stability revealed by structural analyses of chemically treated cypovirus capsids.
Cytoplasmic polyhedrosis virus (CPV, genus Cypovirus) is a unique member of the family Reoviridae which lacks the outer protective shells that exist in all other members, yet exhibits unusual stability. We have analyzed the effects of different acidic, basic, detergent, and urea treatments on CPV capsids. The integrity of the CPV capsids was unaffected under high-pH conditions that disrupted the orthoreovirus inner core, consistent with its ability to maintain structural integrity in extremely alkaline environments during infection. However, it was sensitive to low pH, detergents, and urea, similarly to other viruses in this family. The three-dimensional structure comparisons by electron cryomicroscopy of the intact empty CPV capsid with the "spikeless" capsid whose turrets were removed by chemical treatments revealed the interaction footprint of the turret on the capsid shell. The observed structural changes associated with the removal of the turret suggest critical structural roles of the turret in maintaining capsid integrity in addition to its enzymatic activities.
Zhang
Hong
H
Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, 77030, USA.
Yu
Xue-Kui
XK
Lu
Xing-Ying
XY
Zhang
Jing-Qiang
JQ
Zhou
Z Hong
ZH
D002213:Capsid / Q000737:chemistry; D020285:Cryoelectron Microscopy; D003902:Detergents / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D008958:Models, Molecular; D012087:Reoviridae / Q000737:chemistry* / Q000187:drug effects; D014508:Urea / Q000494:pharmacology
D003902:Detergents; D014508:Urea