RNA chaperone activity of translation initiation factor IF1.
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.
Croitoru
Victor
V
Department of Genetics, Microbiology and Toxicology, Stockholm University, S-10691 Stockholm, Sweden.
Semrad
Katharina
K
Prenninger
Silvia
S
Rajkowitsch
Lukas
L
Vejen
Max
M
Laursen
Brian Søgaard
BS
Sperling-Petersen
Hans Uffe
HU
Isaksson
Leif A
LA
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
D018832:Molecular Chaperones; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins; D012313:RNA