title: Morphological variation of individual Escherichia coli 30S ribosomal subunits in vitro and in situ, as revealed by cryo-electron tomography.
abstract: Cryo-electron tomography has been used to reconstruct the structures of individual ribosomal 30S subunits in Escherichia coli cells treated with rifampicin. Rifampicin inhibits transcription initiation, thus giving depletion of mRNA and accumulation of free 30S and 50S subunits in the cell. Here, we present the 3D morphologies of reconstructed individual 30S ribosomal subunits both in vitro and in situ from E. coli. The head, the platform, and the body of the structures show large conformational movements relative to each other. The particles were grouped into three conformational groups according to the ratio between width and height in the subunit solvent side view. Also, an S15 fusion protein derivative has been used as a physical reporter to localize S15 in the 30S subunit. The results demonstrate a considerable morphological heterogeneity and structural variability among 30S ribosomal subunits.
authors.affiliation: Department of Microbiology, Stockholm University, S-106 91 Stockholm, Sweden.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhao
authors.forename: Lars-Göran
authors.initials: LG
authors.lastname: Ofverstedt
authors.forename: Ulf
authors.initials: U
authors.lastname: Skoglund
authors.forename: Leif A
authors.initials: LA
authors.lastname: Isaksson
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D004926:Escherichia coli / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics / Q000648:ultrastructure; D014644:Genetic Variation; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D009154:Mutation; D011487:Protein Conformation; D012329:RNA, Bacterial / Q000737:chemistry* / Q000648:ultrastructure; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000302:isolation & purification / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000648:ultrastructure; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D012270:Ribosomes / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D012293:Rifampin / Q000494:pharmacology; D014054:Tomography
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D011993:Recombinant Fusion Proteins; D012269:Ribosomal Proteins; C040469:ribosomal protein S30; D012293:Rifampin