U-G-A suppressor of bacteriophage T4 associated with arginine transfer RNA.

A U-G-A suppressor of bacteriophage T4, designated psu4+op, has been isolated and characterized. The transfer RNA species previously shown to have an anticodon sequence complementary to arginine codons is affected by the psu4+op mutation. Wild type and psu4+op arginine tRNAs have the same sequence except for their anticodons, where U-C-U in the wild type species is mutated to U-C-A in the psu4+op species. This mutation is believed to confer U-G-A suppressor activity on the psu4+op arginine tRNA.