The enzyme tRNA-guanine transglycosylase (TGT) chemically modifies transfer RNA (tRNA) and plays a key role in how disease-causing bacteria control the production of proteins needed to cause infection. E. coli TGT is nearly identical to the one found in Shigella, which causes the intestinal infectio n shigellosis. Traditionally, scientists have used E. coli TGT as a primary model to understand how TGT works; however, they have struggled to visualize the atomic structure of E. coli TGT because the protein is difficult to crystallize, limiting their ability to learn more about the enzyme. ...read more read less