Specific structural elements of the t-box riboswitch drive the two-step binding of the tRNA ligand

Jiacheng Zhang, Bhaskar Chetnani, Eric D. Cormack, Dulce Alonso, Wei Liu, Alfonso Mondragón, Jingyi Fei*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


T-box riboswitches are cis-regulatory RNA elements that regulate the expression of proteins involved in amino acid biosynthesis and transport by binding to specific tRNAs and sensing their aminoacylation state. While the T-box modular structural elements that recognize different parts of a tRNA have been identified, the kinetic trajectory describing how these interactions are established temporally remains unclear. Using smFRET, we demonstrate that tRNA binds to the riboswitch in two steps, first anticodon recognition followed by the sensing of the 3’ NCCA end, with the second step accompanied by a T-box riboswitch conformational change. Studies on site-specific mutants highlight that specific T-box structural elements drive the two-step binding process in a modular fashion. Our results set up a kinetic framework describing tRNA binding by T-box riboswitches, and suggest such binding mechanism is kinetically beneficial for efficient, co-transcriptional recognition of the cognate tRNA ligand.

Original languageEnglish (US)
Article numbere39518
StatePublished - Sep 2018

ASJC Scopus subject areas

  • General Immunology and Microbiology
  • General Biochemistry, Genetics and Molecular Biology
  • General Neuroscience


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