Expanding the Scope of Protein Biosynthesis by Altering the Methionyl-tRNA Synthetase Activity of a Bacterial Expression Host Scott Ross was helpful in conducting the 1D TOCSY NMR experiments and Pratip Bhattachary is thanked for assistance in other NMR experiments. We are grateful to Yves Mechulam for a sample of plasmid pBSM547W305F and to Hieronim Jakubowski of UMDNJ-New Jersey Medical School, Newark, New Jersey, for plasmid pGG3. K.L.K. thanks the U.S. Department of Defense for a National Defense Science and Engineering Graduate Fellowship. This work was supported by grants from the Polymers and Genetics Programs of the National Science Foundation and from the U.S. Army Research Office.