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T Box Riboswitch Antiterminator Affinity Modulated by tRNA Structural Elements
Author(s) -
Means John A.,
Wolf Steffen,
Agyeman Akwasi,
Burton Jeremy S.,
Simson Crystal M.,
Hines Jennifer V.
Publication year - 2007
Publication title -
chemical biology and drug design
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.59
H-Index - 77
eISSN - 1747-0285
pISSN - 1747-0277
DOI - 10.1111/j.1747-0285.2007.00476.x
Subject(s) - riboswitch , antitermination , rna , transfer rna , biology , terminator (solar) , base pair , transcription (linguistics) , rna binding protein , microbiology and biotechnology , computational biology , non coding rna , genetics , gene , rna dependent rna polymerase , physics , ionosphere , linguistics , philosophy , astronomy
A unique RNA–RNA interaction occurs between uncharged tRNA and the untranslated mRNA leader region of bacterial T box genes. The interaction results in activation of a transcriptional antitermination molecular switch (riboswitch) by stabilizing an antiterminator RNA element and precluding formation of a competing transcriptional terminator RNA element. The stabilization requires the base pairing of cognate tRNA acceptor end nucleotides with the antiterminator. To develop an appropriate model system for detailed structural studies and to screen for small molecule disruption of this important RNA–RNA interaction, steady‐state fluorescence measurements of antiterminator model RNAs were used to determine the dissociation constant for model tRNA binding. The antiterminator‐binding affinity for the full, minihelix, microhelix, and tetramer tRNA models differed by orders of magnitude. In addition, not all of the tRNA models exhibited functionally relevant binding specificity. The results from these experiments highlight the importance of looking beyond the level of known base pairing interactions when designing functionally relevant models of riboswitch systems.