6YGZ 6YGZ 6ygz tRNA Guanine Transglycosylase (TGT) labelled with 5-fluoro-tryptophan in co-crystallized complex with 6-Amino-4-(2-phenylethyl)-1,7-dihydro-8H-imidazo[4,5-g]quinazolin-8-one 6YGZ-noatom