title: Non-structural proteins P17 and P33 are involved in the assembly of the internal membrane-containing virus PRD1.
abstract: Bacteriophage PRD1, which has been studied intensively at the structural and functional levels, still has some gene products with unknown functions and certain aspects of the PRD1 assembly process have remained unsolved. In this study, we demonstrate that the phage-encoded non-structural proteins P17 and P33, either individually or together, complement the defect in a temperature-sensitive GroES mutant of Escherichia coli for host growth and PRD1 propagation. Confocal microscopy of fluorescent fusion proteins revealed co-localisation between P33 and P17 as well as between P33 and the host chaperonin GroEL. A fluorescence recovery after photobleaching assay demonstrated that the diffusion of the P33 fluorescent fusion protein was substantially slower in E. coli than theoretically calculated, presumably resulting from intermolecular interactions. Our results indicate that P33 and P17 function in procapsid assembly, possibly in association with the host chaperonin complex GroEL/GroES.
authors.affiliation: Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland.
authors.forename: Jenni
authors.initials: J
authors.lastname: Karttunen
authors.affiliation: Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland.
authors.forename: Sari
authors.initials: S
authors.lastname: Mäntynen
authors.affiliation: Stem Cells in Neurological Applications Group, BioMediTech, University of Tampere, Tampere, Finland.
authors.forename: Teemu O
authors.initials: TO
authors.lastname: Ihalainen
authors.affiliation: Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland.
authors.forename: Jaana K H
authors.initials: JK
authors.lastname: Bamford
authors.affiliation: Institute of Biotechnology and Department of Biosciences, University of Helsinki, Biocenter 2, P.O. Box 56 (Viikinkaari 5), FIN-00014 Helsinki, Finland. Electronic address: hanna.oksanen@helsinki.fi.
authors.forename: Hanna M
authors.initials: HM
authors.lastname: Oksanen
mesh_terms: D025622:Bacteriophage PRD1 / Q000502:physiology*; D018834:Chaperonin 60 / Q000378:metabolism; D004926:Escherichia coli / Q000254:growth & development / Q000821:virology*; D006790:Host-Parasite Interactions; D018613:Microscopy, Confocal; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D019065:Virus Assembly; D014779:Virus Replication
chemical_list: D018834:Chaperonin 60; D017361:Viral Nonstructural Proteins
keywords: Assembly; Bacteriophage; Chaperonin; Fluorescence recovery after photobleaching; Fluorescent protein; Membrane virus; Protein localisation