Interaction of Thiostrepton and Elongation Factor-G with the Ribosomal Protein L11-binding Domain

• Published in: The Journal of biological chemistry Vol. 280; no. 4; pp. 2934 - 2943
• Main Authors: Bowen, William S., Van Dyke, Natalya, Murgola, Emanuel J., Lodmell, J. Stephen, Hill, Walter E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 28.01.2005; American Society for Biochemistry and Molecular Biology
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Base Sequence; Crystallography, X-Ray; Dose-Response Relationship, Drug; Escherichia coli - metabolism; Models, Molecular; Molecular Sequence Data; Mutation; Nucleic Acid Conformation; Peptide Elongation Factor G - chemistry; Peptide Elongation Factor G - metabolism; Protein Binding; Protein Biosynthesis; Protein Conformation; Protein Structure, Secondary; Protein Structure, Tertiary; Protein Transport; Ribosomes - chemistry; RNA, Ribosomal - chemistry; RNA, Ribosomal - metabolism; RNA, Ribosomal, 23S - chemistry; Thiostrepton - pharmacology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M407008200

Ribosomal protein L11 and the L11 binding region of ribosomal RNA constitute an important domain involved in active functions of the ribosome during translation. We studied the effects of L11 knock-out and truncation mutations on the structure of the rRNA in this region and on its interactions with a translation elongation factor and the antibiotic thiostrepton. The results indicated that the structure of the L11-binding rRNA becomes conformationally flexible when ribosomes lack the entire L11 protein, but not when the C-terminal domain is present on ribosomes. Probing wild type and mutant ribosomes in the presence of the antibiotic thiostrepton and elongation factor-G (EF-G) rigorously localized the binding cleft of thiostrepton and suggested a role for the rRNA in the L11-binding domain in modulating factor binding. Our results also provide evidence that the structure of the rRNA stabilized by the C-terminal domain of L11 is necessary to stabilize EF-G binding in the post-translocation state, and thiostrepton may modulate this structure in a manner that interferes with the ribosome-EF-G interaction. The implications for recent models of thiostrepton activity and factor interactions are discussed.