title: Direct localization of the tRNAs within the elongating ribosome by means of neutron scattering (proton-spin contrast-variation).
abstract: A new technique for neutron scattering, the proton-spin contrast-variation, improves the signal-to-noise ratio more than one order of magnitude as compared to conventional techniques. The improved signal enables small RNA ligands within a large deuterated ribonucleic acid-protein complex to be measured. We used this technique to determine the positions of the two tRNAs within the elongating ribosome before and after translocation. Using a four-sphere model for each of the L-shaped tRNAs, unequivocal solutions were found for the localization of the mass centre of both tRNAs. The centre of gravity is located in the interface cavity separating the ribosomal subunits near the neck of the 30 S subunit. It moves during translocation by 12(+/-4) A towards the head of the 30 S subunit and slightly towards the L1 protuberance of the 50 S subunit.
authors.affiliation: Max-Planck-Institut für Molekulare Genetik, AG Ribosomen, Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Wadzack
authors.forename: N
authors.initials: N
authors.lastname: Burkhardt
authors.forename: R
authors.initials: R
authors.lastname: Jünemann
authors.forename: G
authors.initials: G
authors.lastname: Diedrich
authors.forename: K H
authors.initials: KH
authors.lastname: Nierhaus
authors.forename: J
authors.initials: J
authors.lastname: Frank
authors.forename: P
authors.initials: P
authors.lastname: Penczek
authors.forename: W
authors.initials: W
authors.lastname: Meerwinck
authors.forename: M
authors.initials: M
authors.lastname: Schmitt
authors.forename: R
authors.initials: R
authors.lastname: Willumeit
authors.forename: H B
authors.initials: HB
authors.lastname: Stuhrmann
mesh_terms: D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009502:Neutrons; D010441:Peptide Chain Elongation, Translational; D011522:Protons; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D012335:RNA, Ribosomal / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D012343:RNA, Transfer / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D012542:Scattering, Radiation
chemical_list: D011522:Protons; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D012343:RNA, Transfer