Demonstration of the UAA Ochre Codon in Bakers' Yeast by Amino Acid Replacements in Iso-1-cytochrome c

摘要

When acting to revert the cyl-9 UAA nonsense lesion, x-rays, some alkylating chemicals, and spontaneous events cause substitutions of A.T pairs with no apparent selectivity, whereas ultraviolet irradiation and nitrous acid selectively induce A.T->G.C. Single substitutions account for all 45 reversions either obtained spontaneously or induced by eight different mutagenic treatments.nReinitiating past the nonsense codon at position 2 fails to occur at a detectable level, although an efficient translation initiation site is accessible by mutation of the AAG, lysine 4 codon to AUG, in other mutant strains that lack the normal initiation codon.