title: Interaction of trigger factor with the ribosome.
abstract: The trigger factor of Escherichia coli is a prolyl isomerase and a chaperone. It interacts with the ribosome and affects the folding of newly formed protein chains. Therefore, the dynamics of the interactions of trigger factor with the ribosome and with unfolded protein chains should be tailored for this function. Previously, we had found that binding of unfolded proteins to trigger factor is fast and that the lifetime of the complex between these two components is only about 100 ms. Here, we have labeled the trigger factor in its amino-terminal, ribosome-binding domain with a fluorescent dye and investigated how it interacts with the ribosome. We found that this association, as well as the dissociation of the complex, are rather slow processes. The average lifetime of the complex is about 30 seconds (at 20 degrees C). The strong differences in the dynamics of the interactions of trigger factor with the ribosome and with protein substrates might ensure that, on the one hand, trigger factor remains bound to the ribosome while a protein chain is being synthesized, and, on the other hand, allows it to scan the newly formed protein for prolyl bonds that need catalysis of isomerization.
authors.affiliation: Laboratorium für Biochemie, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Raimund
authors.initials: R
authors.lastname: Maier
authors.forename: Barbara
authors.initials: B
authors.lastname: Eckert
authors.forename: Christian
authors.initials: C
authors.lastname: Scholz
authors.forename: Hauke
authors.initials: H
authors.lastname: Lilie
authors.forename: Franz-Xaver
authors.initials: FX
authors.lastname: Schmid
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives* / Q000378:metabolism; D001665:Binding Sites; D001667:Binding, Competitive; D002384:Catalysis; D002623:Chemistry Techniques, Analytical; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D005453:Fluorescence; D007536:Isomerism; D007700:Kinetics; D009154:Mutation; D019696:Peptidylprolyl Isomerase / Q000737:chemistry / Q000378:metabolism*; D011392:Proline / Q000737:chemistry; D011485:Protein Binding; D017510:Protein Folding; D012270:Ribosomes / Q000378:metabolism*; D014461:Ultracentrifugation
chemical_list: C122155:6-bromoacetyl-2-dimethylaminonaphthalene; D029968:Escherichia coli Proteins; D011392:Proline; D015081:2-Naphthylamine; C403324:trigger factor, E coli; D019696:Peptidylprolyl Isomerase