Anna Biela Anna Biela Jakub Nowak Jakub Nowak Artur Biela Artur Biela Sunandan Mukherjee Sunandan Mukherjee Seyed Naeim Moafinejad Seyed Naeim Moafinejad Satyabrata Maiti Satyabrata Maiti Andrzej Chramiec-Glabik Andrzej Chramiec-Glabik Rahul Mehta Rahul Mehta Jakub Jezowski Jakub Jezowski Dominika Dobosz Dominika Dobosz Priyanka Dahate Priyanka Dahate Veronique Arluison Veronique Arluison Frank Wien Frank Wien Paulina Indyka Paulina Indyka Michal Rawski Michal Rawski Janusz M. Bujnicki Janusz M. Bujnicki Ting-Yu Lin Ting-Yu Lin Sebastian Glatt Sebastian Glatt Wiley 2025 Transfer RNAs (tRNAs) are ubiquitous non-coding RNA molecules required to translate mRNA-encoded sequence information into nascent polypeptide chains. Their relatively small size and heterogenous patterns of their RNA modifications have impeded the systematic structural characterization of individual tRNAs. Here, we use single-particle cryo-EM to determine the structures of four human tRNAs before and after incorporation of pseudouridines (Ψ). Following post-transcriptional modifications by distinct combinations of human pseudouridine synthases, we find that tRNAs become stabilized and undergo specific local structural changes. We establish interactions between the D- and T-arms as the key linchpin in the tertiary structure of tRNAs. Our structures of human tRNAs highlight the vast potential of cryo-EM combined with biophysical measurements and computational simulations for structure-function analyses of tRNAs and other small, folded RNA domains. PDFDocument eng 2026-02-09T10:07:41.967669Z 2025 tRNA Cryo-EM RNA Modifications RNA Folding Molecular Dynamics Simulation 10698157 b application/pdf http://creativecommons.org/licenses/by/4.0/