Abvance Biotech srl 1 article published in JoVE Biochemistry Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function Francisco J. Fernández1,2,3, Sara Gómez1, Sergio Navas-Yuste1, Miguel López-Estepa1, M. Cristina Vega1 1Department of Physical Chemical Biology, Center for Biological Research (CIB-CSIC), Spanish National Research Council (CSIC), 2Department of Immunology, Complutense University School of Medicine, 3Abvance Biotech srl A protocol is presented for the production of tRNA(UUU) and the analysis of tRNA(UUU) in complex with the enzyme TcdA by agarose gel retardation assays.