title: RNA chaperone activity of translation initiation factor IF1.
abstract: Translation initiation factor IF1 is an indispensable protein for translation in prokaryotes. No clear function has been assigned to this factor so far. In this study we demonstrate an RNA chaperone activity of this protein both in vivo and in vitro. The chaperone assays are based on in vivo or in vitro splicing of the group I intron in the thymidylate synthase gene (td) from phage T4 and an in vitro RNA annealing assay. IF1 wild-type and mutant variants with single amino acid substitutions have been analyzed for RNA chaperone activity. Some of the IF1 mutant variants are more active as RNA chaperones than the wild-type. Furthermore, both wild-type IF1 and mutant variants bind with high affinity to RNA in a band-shift assay. It is suggested that the RNA chaperone activity of IF1 contributes to RNA rearrangements during the early phase of translation initiation.
authors.affiliation: Department of Genetics, Microbiology and Toxicology, Stockholm University, S-10691 Stockholm, Sweden.
authors.forename: Victor
authors.initials: V
authors.lastname: Croitoru
authors.forename: Katharina
authors.initials: K
authors.lastname: Semrad
authors.forename: Silvia
authors.initials: S
authors.lastname: Prenninger
authors.forename: Lukas
authors.initials: L
authors.lastname: Rajkowitsch
authors.forename: Max
authors.initials: M
authors.lastname: Vejen
authors.forename: Brian Søgaard
authors.initials: BS
authors.lastname: Laursen
authors.forename: Hans Uffe
authors.initials: HU
authors.lastname: Sperling-Petersen
authors.forename: Leif A
authors.initials: LA
authors.lastname: Isaksson
mesh_terms: D019943:Amino Acid Substitution; D024202:Electrophoretic Mobility Shift Assay; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D014176:Protein Biosynthesis; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018832:Molecular Chaperones; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins; D012313:RNA