Stepping transfer messenger RNA through the ribosome.
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.
Shpanchenko
Olga V
OV
Department of Chemistry, M. V. Lomonosov Moscow State University, 119899, Moscow, Russia.
Zvereva
Maria I
MI
Ivanov
Pavel V
PV
Bugaeva
Elizaveta Y
EY
Rozov
Alexey S
AS
Bogdanov
Alexey A
AA
Kalkum
Markus
M
Isaksson
Leif A
LA
Nierhaus
Knud H
KH
Dontsova
Olga A
OA
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*
D012329:RNA, Bacterial; D012333:RNA, Messenger; C096222:tmRNA; D012343:RNA, Transfer