title: Structural and functional analysis of the E. coli NusB-S10 transcription antitermination complex.
abstract: Protein S10 is a component of the 30S ribosomal subunit and participates together with NusB protein in processive transcription antitermination. The molecular mechanisms by which S10 can act as a translation or a transcription factor are not understood. We used complementation assays and recombineering to delineate regions of S10 dispensable for antitermination, and determined the crystal structure of a transcriptionally active NusB-S10 complex. In this complex, S10 adopts the same fold as in the 30S subunit and is blocked from simultaneous association with the ribosome. Mass spectrometric mapping of UV-induced crosslinks revealed that the NusB-S10 complex presents an intermolecular, composite, and contiguous binding surface for RNAs containing BoxA antitermination signals. Furthermore, S10 overproduction complemented a nusB null phenotype. These data demonstrate that S10 and NusB together form a BoxA-binding module, that NusB facilitates entry of S10 into the transcription machinery, and that S10 represents a central hub in processive antitermination.
authors.affiliation: Research Group X-Ray Crystallography, Max-Planck-Institute for Biophysical Chemistry, D-37077 Göttingen, Germany.
authors.forename: Xiao
authors.initials: X
authors.lastname: Luo
authors.forename: He-Hsuan
authors.initials: HH
authors.lastname: Hsiao
authors.forename: Mikhail
authors.initials: M
authors.lastname: Bubunenko
authors.forename: Gert
authors.initials: G
authors.lastname: Weber
authors.forename: Donald L
authors.initials: DL
authors.lastname: Court
authors.forename: Max E
authors.initials: ME
authors.lastname: Gottesman
authors.forename: Henning
authors.initials: H
authors.lastname: Urlaub
authors.forename: Markus C
authors.initials: MC
authors.lastname: Wahl
mesh_terms: D001483:Base Sequence; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011485:Protein Binding; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D012329:RNA, Bacterial / Q000378:metabolism; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D013329:Structure-Activity Relationship; D013499:Surface Properties; D013728:Terminator Regions, Genetic; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D029968:Escherichia coli Proteins; C074952:NusB protein, E coli; D012329:RNA, Bacterial; D012269:Ribosomal Proteins; D014157:Transcription Factors; C029537:ribosomal protein S10