F-19 NMR investigation of F-1-ATPase of Escherichia coli using fluorotryptophan labeling

Growth of Escherichia coli in the presence of glyphosate, an inhibitor of a romatic amino acid biosynthesis, has permitted the production of proton-dis locating ATPase that is specifically labeled with 5-fluorotryptophan. Five sets of F-19 resonances could be assigned to each tryptophan residue by lau ryldimethylamine oxide and carboxypeptidase treatment. On labeling with 4-c hloro-7-nitro-benzofurazan, the label attached to beta 155Lys, which is kno wn to be in the catalytic site, which caused one of the residues, beta 108T rp, to become nonequivalent, F-19 NMR spectroscopic investigation of intern ally fluorotryptophan-labeled F-1-ATPase will provide valuable information about the asymmetric nature of F-1-ATPase and the conformational changes in duced by ligand binding.