title: Localization of the release factor-2 binding site on 70 S ribosomes by immuno-electron microscopy.
abstract: In protein synthesis Escherichia coli release factor-2 binds to 70 S ribosomes when the termination codon UAA or UGA appears at the decoding site. The weak interaction between factor and ribosome has been stabilized in vitro by chemical cross-linking. Factor so bound can still be recognized by a specific antibody to release factor-2. Examination of the resulting immuno-complexes by electron microscopy revealed 70 S ribosomes in different projection forms, and the occasional dissociated subunit labelled with antibody. The antibody-binding site was localized on previously characterized 70 S projection forms, and its three-dimensional localization on the 70 S model established. The release factor-2-binding site was found to be positioned at the ribosomal subunit interface, comprising the stalk-protuberance region of the large subunit and the head-neck region of the concave side of the small subunit.
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin, New Zealand.
authors.forename: B
authors.initials: B
authors.lastname: Kastner
authors.forename: C N
authors.initials: CN
authors.lastname: Trotman
authors.forename: W P
authors.initials: WP
authors.lastname: Tate
mesh_terms: D001665:Binding Sites; D004926:Escherichia coli / Q000378:metabolism*; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D010454:Peptide Termination Factors / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D010454:Peptide Termination Factors; C041460:peptide chain termination release factor 2