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Updated: Apr 15, 2026

Site-Directed Mutagenesis for In Vitro and In Vivo Experiments Exemplified with RNA Interactions in Escherichia Coli
Published on: February 5, 2019
Modulation of conformational changes in helix 69 mutants by pseudouridine modifications
Jun Jiang1, Daya Nidhi Kharel1, Christine S Chow1
1Department of Chemistry, Wayne State University, Detroit, MI 48202, United States.
Abstract:
Centrally located at the ribosomal subunit interface and mRNA tunnel, helix 69 (H69) from 23S rRNA participates in key steps of translation. Ribosome activity is influenced by three pseudouridine modifications, which modulate the structure and conformational behavior of H69. To understand how H69 is affected by the presence of pseudouridine in combination with sequence changes, the biophysical properties of wild-type H69 and representative mutants (A1912G, U1917C, and A1919G) were examined. Results from NMR and circular dichroism spectroscopy indicate that pH-dependent structural changes of wild-type H69 and the chosen mutants are modulated by pseudouridine and loop sequence. The effects of the mutations on global stability of H69 are negligible; however, pseudouridine stabilizes H69 at low pH conditions. Alterations to induced conformational changes of H69 likely result in compromised function, as indicated by previous biological studies.
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