title: The major capsid protein of the lipid-containing bacteriophage PR4 is the precursor of two other capsid proteins.
abstract: We report that capsid proteins P16 and P18 of bacteriophage PR4 are synthesized by post-translational processing of a portion of the major capsid protein, P2. A polyclonal antibody raised against purified P2 reacted with P16 and P18 as well as with P2. A monoclonal antibody reacted with both P2 and P18. The amino acid sequences of the N-termini of P2 and P18 exactly matched, indicating that P18 is derived from the N-terminal segment of P2. These data were confirmed by the analysis of the proteins encoded by various nonsense and missense P2 mutants. The 3129-bp MnlI-C fragment of the PR4 genome was shown to encode P2. The nucleotide sequence of this fragment was obtained and a single continuous ORF was found to encode P2, thus excluding introns and transcript processing in the production of P16 and P18. The DNA segment contained eight ORFs sized > 200 bp and the genes encoding proteins P6 and P6A as well as P2 were mapped by marker rescue analysis. We also report the isolation and characterization of a new class of P2 missense mutants.
authors.affiliation: Department of Microbiology, University of Illinois, Urbana 61801.
authors.forename: H
authors.initials: H
authors.lastname: Myung
authors.forename: T
authors.initials: T
authors.lastname: Vanden Boom
authors.forename: J E
authors.initials: JE
authors.lastname: Cronan
mesh_terms: D002213:Capsid / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D003090:Coliphages / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D005814:Genes, Viral; D008563:Membrane Lipids / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010743:Phospholipids / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D012483:Salmonella Phages / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D015678:Viral Structural Proteins / Q000235:genetics
chemical_list: D008563:Membrane Lipids; D010743:Phospholipids; D015678:Viral Structural Proteins