Ringer D, Quiggle K, Chládek S
Biochemistry. 1975 Feb 11;14(3):514-20. doi: 10.1021/bi00674a009.
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.
利用以下氨基酰寡核苷酸作为氨酰 - tRNA 3'末端的模型，研究了2'-和3'-O-氨基酰 - tRNA的3'末端与大肠杆菌核糖体肽基转移酶A位点的相互作用：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和C-A(2'H)Gly。C-A-Phe、C-A(2'Phe)H、C-A(2'H)Phe、C-A(2'Gly)H和C-A(2'H)Gly抑制了Ac-(14C)Phe从Ac-(14C)Phe-tRNA-oly(U)-70S核糖体复合物向嘌呤霉素（10-4和10-5 M）的转移。对C-A(2'Phe)H抑制Ac(14C)Phe-嘌呤霉素形成的动力学分析未能显示出简单的竞争性抑制。在过量脱酰基tRNA存在下，C-A-C-C-A-(14C)Phe与70S核糖体的结合也受到C-A-Phe、C-A(2'Phe)H、C-A(2'H)Phe、C-A(2'Phe)Me和C-A(2'Me)Phe的抑制。似乎肽基转移酶的受体位点可以识别2'-或3'-O-AA-tRNA的3'末端，对2'异构体更偏好。因此可以推断，2'-O-AA-tRNA可能在肽键形成之前就与核糖体结合，并且肽基转移酶专门用作受体的3'-O-AA-tRNA是由2'导致3'转酰基作用在肽基转移酶A位点发生而提供的。
