Mutants of Su+7 tRNA include a functional tRNA with an altered T pseudo uracil CG sequence.
Su+7 tRNA, the amber-suppressing anticodon mutant of tRNA(Trp) (E. coli), also relaxes stringent control. Further mutant Su+7 tRNAs have been isolated that have lost this regulatory effect. The sequence changes we have observed are a unique set. They include partially active suppressor tRNAs with a C to A change in the T pseudo uracil CG common sequence and in the anticodon stem. The activity of the T pseudo uracil CG and anticodon-stem mutants suggests that neither sequence is essential for ribosomal function. The third mutated site, a D-stem alteration, dramatically disturbs tRNA maturation. The mutations add to our knowledge of tRNA function, particularly with regard to the dispensability of the T pseudo uracil CG sequence for activity at the ribosomal A site.
D001483:Base Sequence; D005786:Gene Expression Regulation; D006159:Guanosine Tetraphosphate / Q000378:metabolism; D009154:Mutation; D009694:Nucleic Acid Precursors / Q000378:metabolism; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000235:genetics*; D013329:Structure-Activity Relationship; D013489:Suppression, Genetic
D009694:Nucleic Acid Precursors; D006159:Guanosine Tetraphosphate; D012343:RNA, Transfer