title: Periodic conformational changes in rRNA: monitoring the dynamics of translating ribosomes.
abstract: In protein synthesis, a tRNA transits the ribosome via consecutive binding to the A (acceptor), P (peptidyl), and E (exit) site; these tRNA movements are catalyzed by elongation factor G (EF-G) and GTP. Site-specific Pb2+ cleavage was applied to trace tertiary alterations in tRNA and all rRNAs on pre- and posttranslocational ribosomes. The cleavage pattern of deacylated tRNA and AcPhe-tRNA changed individually upon binding to the ribosome; however, these different conformations were unaffected by translocation. On the other hand, translocation affects 23S rRNA structure. Significantly, the Pb2+ cleavage pattern near the peptidyl transferase center was different before and after translocation. This structural rearrangement emerged periodically during elongation, thus providing evidence for a dynamic and mobile role of 23S rRNA in translocation.
authors.affiliation: Institute of Biochemistry, Vienna Biocenter, University of Vienna, Austria.
authors.forename: N
authors.initials: N
authors.lastname: Polacek
authors.forename: S
authors.initials: S
authors.lastname: Patzke
authors.forename: K H
authors.initials: KH
authors.lastname: Nierhaus
authors.forename: A
authors.initials: A
authors.lastname: Barta
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012360:RNA, Transfer, Phe / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D012338:RNA, Ribosomal, 23S; D012360:RNA, Transfer, Phe