Binding of misacylated tRNAs to the ribosomal A site.
To test whether the ribosome displays specificity for the esterified amino acid and the tRNA body of an aminoacyl-tRNA (aa-tRNA), the stabilities of 4 correctly acylated and 12 misacylated tRNAs in the ribosomal A site were determined. By introducing the GAC (valine) anticodon into each tRNA, a constant anticodon.codon interaction was maintained, thus removing concern that different anticodon.codon strengths might affect the binding of the different aa-tRNAs to the A site. Surprisingly, all 16 aa-tRNAs displayed similar dissociation rate constants from the A site. These results suggest that either the ribosome is not specific for different amino acids and tRNA bodies when intact aa-tRNAs are used or the specificity for the amino acid side chain and tRNA body is masked by a conformational change upon aa-tRNA release.
Dale
Taraka
T
Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, IL 60208, USA.
Uhlenbeck
Olke C
OC
D000215:Acylation; D000926:Anticodon / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D003062:Codon / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010444:Peptide Elongation Factor Tu / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D046249:Transfer RNA Aminoacylation
D000926:Anticodon; D003062:Codon; D012333:RNA, Messenger; D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu