title: ϕ29 Scaffolding and connector structure-function relationship studied by trans-complementation.
abstract: A dodecamer of connector protein forms a conduit at a unique five-fold vertex in the capsid of many dsDNA-containing viruses providing the means for DNA entry and egress. The molecular mechanism guiding the incorporation of one connector per procapsid remains obscure; however, a recent bacteriophage ϕ29 model suggests that incorporation is coupled to nucleation between the connector and scaffolding proteins and particular amino acids may promote interactions between the two proteins. To test this model in vivo, a trans-complementation system using cloned scaffolding genes was implemented and tested for the ability to complement a ϕ29 amber-scaffolding strain. Wild type scaffolding gene induction resulted in efficient virion production, whereas synthesis of mutant scaffolding proteins displayed various phenotypes. Biochemical analyses of the resultant particles substantiate the previously identified amino acid residues in connector incorporation. Furthermore, kinetic studies of virion production using the in vivo trans-complementation system support the nucleation model.
authors.affiliation: Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: James E
authors.initials: JE
authors.lastname: Cherwa
authors.forename: Peter E
authors.initials: PE
authors.lastname: Prevelige
mesh_terms: D017103:Bacillus Phages / Q000235:genetics / Q000502:physiology*; D005816:Genetic Complementation Test; D046911:Macromolecular Substances / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000235:genetics / Q000378:metabolism*; D019065:Virus Assembly
chemical_list: D046911:Macromolecular Substances; D014764:Viral Proteins
keywords: Bacteriophage ϕ29; Procapsid; Scaffold; Virus assembly