Fluorescence probing of T box antiterminator RNA: Insights into riboswitch discernment of the tRNA discriminator base

• Published in: Biochemical and biophysical research communications Vol. 389; no. 4; pp. 616 - 621
• Main Authors: Means, John A., Simson, Crystal M., Zhou, Shu, Rachford, Aaron A., Rack, Jeffrey J., Hines, Jennifer V.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 27.11.2009
• Subjects: 2-Aminopurine; 5' Untranslated Regions; Fluorescence; Gene Expression Regulation, Bacterial; Gram-Positive Bacteria - genetics; Magnesium - chemistry; Magnesium - metabolism; Nucleic Acid Conformation; Ribosomes - metabolism; Riboswitch; RNA; RNA, Bacterial - chemistry; RNA, Bacterial - metabolism; RNA, Transfer - chemistry; RNA, Transfer - metabolism; Spectrometry, Fluorescence; T box; Terminator Regions, Genetic; Transcription; T box; Fluorescence; Riboswitch; RNA; Transcription; 2-Aminopurine
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2009.09.037

The T box transcription antitermination riboswitch is one of the main regulatory mechanisms utilized by Gram-positive bacteria to regulate genes that are involved in amino acid metabolism. The details of the antitermination event, including the role that Mg 2+ plays, in this riboswitch have not been completely elucidated. In these studies, details of the antitermination event were investigated utilizing 2-aminopurine to monitor structural changes of a model antiterminator RNA when it was bound to model tRNA. Based on the results of these fluorescence studies, the model tRNA binds the model antiterminator RNA via an induced-fit. This binding is enhanced by the presence of Mg 2+, facilitating the complete base pairing of the model tRNA acceptor end with the complementary bases in the model antiterminator bulge.