University of Veterinary Medicine Vienna Determining the effects of pseudouridine incorporation on human tRNAs 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. en TEXT journal article Wissenschaftlicher Artikel Articolo di rivista Testo Articolo di rivista Text journal article Text Wissenschaftlicher Artikel tRNA Cryo-EM RNA Modifications RNA Folding Molecular Dynamics Simulation 2025 2025 Anna Biela Jakub Nowak Artur Biela Sunandan Mukherjee Seyed Naeim Moafinejad Satyabrata Maiti Andrzej Chramiec-Glabik Rahul Mehta Jakub Jezowski Dominika Dobosz Priyanka Dahate Veronique Arluison Frank Wien Paulina Indyka Michal Rawski Janusz M. Bujnicki Ting-Yu Lin Sebastian Glatt Wiley