Recognition of the 3' terminus of 2'-O-aminoacyl transfer ribonucleic acid by the acceptor site of ribosomal peptidyltransferase.
The interaction of the 3' terminus of 2'- and 3'-O-aminoacyl-tRNA with the peptidyltransferase A site of Escherichia coli ribosomes has been studied using the following aminoacyl oligonucleotides as models of the 3' terminus of AA-tRNA: C-A-Phe, C-A(2'Phe)H, C-A(2'H)Phe, C-A(2'Phe)Me, C-A(2'Me)Phe, C-A(2'Gly)H, and C-A(2'H)Gly. The transfer of Ac-(14C)Phe from the Ac-(14C)Phe-tRNA-oly(U)-70S ribosome complex to puromycin (10-4 and 10-5 M) was inhibited by C-A-Phe, C-A(2'Phe)H, C-A(2'H)Phe, C-A(2'Gly)H, and C-A(2'H)Gly. Kinetic analysis of the inhibition of Ac(14C)Phe-puromycin formation by C-A(2'Phe)H failed to show simple competitive inhibition. Binding of C-A-C-C-A-(14C)Phe to 70S ribosomes in the presence of an excess of deacylated tRNA was also inhibited by C-A-Phe, C-A(2'Phe)H, C-A(2'H)Phe, C-A(2'Phe)Me, and C-A(2'Me)Phe. It appears that the acceptor site of peptidyltransferase can recognize the 3' terminus of either 2'- or 3'-O-AA-tRNA, with preference for the 2' isomer. It therefore follows that 2'-O-AA-tRNA amy be bound to ribosomes prior to peptide bone formation and that 3'-O-AA-tRNA, which is used exclusively by peptidyltransferase as an acceptor, is supplied by 2' leads to 3' transacylation occuring at the peptidyltransferase A site.
D000217:Acyltransferases / Q000378:metabolism*; D001665:Binding Sites; D004926:Escherichia coli / Q000378:metabolism; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000494:pharmacology; D010452:Peptide Biosynthesis; D010445:Peptide Elongation Factors; D010649:Phenylalanine; D011072:Poly U; D011691:Puromycin; D012343:RNA, Transfer / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D046249:Transfer RNA Aminoacylation
D009841:Oligonucleotides; D010445:Peptide Elongation Factors; D011072:Poly U; D010649:Phenylalanine; D011691:Puromycin; D012343:RNA, Transfer; D000217:Acyltransferases