IDENTIFICATION OF A SITE ON 18-S RIBOSOMAL-RNA OF HUMAN PLACENTA RIBOSOMES IN THE REGION OF THE MESSENGER-RNA BINDING CENTER

The affinity labeling of human placenta 80 S ribosomes by 4-(N-2-chloroethyl-N-methylamino) benzyl-5′-phosphamide of hexauridylate was studied. This mRNA analog has normal coding properties because its binding to placenta ribosomes significantly increases in the presence of cognate tRNAPhe. Incubation of the mRNA analog in the complex with the ribosomes and Phe-tRNAPhe leads to its covalent attachment exclusively to the small subunit (mainly to 18 S rRNA). The site of the reaction has been identified by hybridization experiments to be located within positions 975 to 1055 of 18 S rRNA. The identified fragment is located in a highly conserved part of the small subunit rRNA domain II. © 1990 Academic Press Limited.