title: 3.88 A structure of cytoplasmic polyhedrosis virus by cryo-electron microscopy.
abstract: Cytoplasmic polyhedrosis virus (CPV) is unique within the Reoviridae family in having a turreted single-layer capsid contained within polyhedrin inclusion bodies, yet being fully capable of cell entry and endogenous RNA transcription. Biochemical data have shown that the amino-terminal 79 residues of the CPV turret protein (TP) is sufficient to bring CPV or engineered proteins into the polyhedrin matrix for micro-encapsulation. Here we report the three-dimensional structure of CPV at 3.88 A resolution using single-particle cryo-electron microscopy. Our map clearly shows the turns and deep grooves of alpha-helices, the strand separation in beta-sheets, and densities for loops and many bulky side chains; thus permitting atomic model-building effort from cryo-electron microscopy maps. We observed a helix-to-beta-hairpin conformational change between the two conformational states of the capsid shell protein in the region directly interacting with genomic RNA. We have also discovered a messenger RNA release hole coupled with the mRNA capping machinery unique to CPV. Furthermore, we have identified the polyhedrin-binding domain, a structure that has potential in nanobiotechnology applications.
authors.affiliation: Department of Pathology and Laboratory Medicine, The University of Texas Medical School at Houston, Houston, Texas 77030, USA.
authors.forename: Xuekui
authors.initials: X
authors.lastname: Yu
authors.forename: Lei
authors.initials: L
authors.lastname: Jin
authors.forename: Z Hong
authors.initials: ZH
authors.lastname: Zhou
mesh_terms: D000818:Animals; D012831:Bombyx / Q000821:virology; D036022:Capsid Proteins / Q000737:chemistry / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D016679:Genome, Viral / Q000502:physiology; D007814:Larva / Q000821:virology; D008958:Models, Molecular; D012315:RNA Caps / Q000235:genetics / Q000378:metabolism; D034443:RNA Transport; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D012087:Reoviridae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*
chemical_list: D036022:Capsid Proteins; D012315:RNA Caps; D012367:RNA, Viral