tRNATrpAcylation by TrpRS Urzyme. A. Model of the putative interaction between TrpRS Urzyme and tRNATrp, derived from the crystal structure of the complex between human TrpRS and tRNATrp. Autoradiograms documenting the acylation of tRNATrp by Wild Type TrpRS, TrpRS Urzyme, and two intermediate modular constructs, containing either CP1 or the anticodon-binding domain. B. Model for interaction of tRNAHis with HisRS4 Urzyme and autoradiograms showing acylation by HisRS1, 2, and 4 as in A. Spheres show Trp-5’AMP, and His-5’ sulfoamyladenylate. These data were published originally in  © The American Society for Biochemistry and Molecular Biology.