the requirement for ribothymidine and pseudouridine in the tpsicg loop of trna for its activity in the ribosome and trna-stimulated synthesis of guanosine 5'-triphosphate 3'-diphosphate ( pppgpp ) by stringent factor has been tested by the use of a purified trnaphe ( 883 pmol of phenylalanine incorporated/a260 unit ) in which 92 % of the pseudouridine , 98 % of the ribothymidine , 98 % of the dihydrouridine , and 88 % of the uridines were substituted by 5-fluorouridine .
C0033846
pseudouridine
C0041984
uridines