title: Stepping transfer messenger RNA through the ribosome.
abstract: tmRNA (transfer messenger RNA) is a unique molecule used by all bacteria to rescue stalled ribosomes and to mark unfinished peptides with a specific degradation signal. tmRNA is recruited by arrested ribosomes in which it facilitates the translational switch from cellular mRNA to the mRNA part of tmRNA. Small protein B (SmpB) is a key partner for the trans-translation activity of tmRNA both in vivo and in vitro. It was shown that SmpB acts at the initiation step of the trans-translation process by facilitating tmRNA aminoacylation and binding to the ribosome. Little is known about the subsequent steps of trans-translation. Here we demonstrated the first example of an investigation of tmRNA.ribosome complexes at different stages of trans-translation. Our results show that the structural element at the position of tmRNA pseudoknot 3 remains intact during the translation of the mRNA module of tmRNA and that it is localized on the surface of the ribosome. At least one SmpB molecule remains bound to a ribosome.tmRNA complex isolated from the cell when translation is blocked at different positions within the mRNA part of tmRNA.
authors.affiliation: Department of Chemistry, M. V. Lomonosov Moscow State University, 119899, Moscow, Russia.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Shpanchenko
authors.forename: Maria I
authors.initials: MI
authors.lastname: Zvereva
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Ivanov
authors.forename: Elizaveta Y
authors.initials: EY
authors.lastname: Bugaeva
authors.forename: Alexey S
authors.initials: AS
authors.lastname: Rozov
authors.forename: Alexey A
authors.initials: AA
authors.lastname: Bogdanov
authors.forename: Markus
authors.initials: M
authors.lastname: Kalkum
authors.forename: Leif A
authors.initials: LA
authors.lastname: Isaksson
authors.forename: Knud H
authors.initials: KH
authors.lastname: Nierhaus
authors.forename: Olga A
authors.initials: OA
authors.lastname: Dontsova
mesh_terms: D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000235:genetics* / Q000378:metabolism*
chemical_list: D012329:RNA, Bacterial; D012333:RNA, Messenger; C096222:tmRNA; D012343:RNA, Transfer