[Peptidyl transferase center of ribosomes. I. Difference in the substrate specificity of the acceptor and donor portions]. / Peptidiltransferaznyi tsentr ribosom. I. Razlichie v substratnoi spetsifichnosti aktseptornogo i donornogo uchastkov.

Some model substrates of the peptidyl transferase centre of E. coli MRE-600 ribosomes were synthesised and tested in a cell-free system without a template. In these substances the nucleic bases were linked covalently with the ribose residue or had a limited rotation about the glycosidic bond. 3'(2')-O-(N-formylmethionyl)-8-bromoadenosine 5'-phosphate and 3'(2')-O-phenylalanyl-8,5'-anhydro-8-mercaptoadenosine were shown to possess a high peptide donor and acceptor activity correspondingly. Contrary to that 3'(2')-O-phenylalanyl-8-bromoadenosine was practically inactive as a peptide acceptor and 3'(2')-O-(N-formylmethionyl)-8,5'-anhydro-8-mercaptoadenosine had no peptide donor activity at all. PMR and CD spectra of the compounds synthesised were investigated. The significance of conformation of the model substrates on their activity is discussed.

Synthesis of acylamino acid esters of nucleoside 5'-phosphates and their investigation with PMR and CD spectra.

The acylamino acid esters of nucleoside 5'-phosphates are synthesized via condensation of N-(N'-acylaminoacyl) imidazoles with nucleoside 5'-phosphates. The PMR and CD spectra of the esters obtained are studied. The 3'-isomers of the substances under study are observed to have a shift in the conformational N in equilibrium S equilibrium of the carbohydrate moiety in favour of the S-form as compared to the initial nucleosides and their 2'-acyl esters.