NUCLEOTIDES OF 18S RIBOSOMAL-RNA SURROUNDING MESSENGER-RNA AT THE DECODING SITE OF TRANSLATING HUMAN RIBOSOME AS REVEALED FROM THE CROSS-LINKING DATA

mRNA analogs, l-N-methylamino)benzylmethyl-[5'-P-32]-phosphamide deriv atives of oligoribonucleotides pAUGU(n) (n = 0, 3 or 6), were used for affinity labelling of human 80S ribosomes in complexes with codon-ant icodon interaction at the P-site. These complexes were obtained in the presence of fractionated lysate from rabbit reticulocytes deprived of endogenous ribosomes and mRNAs. In all cases, 40S subunits were label led preferentially. Within the subunits, both ribosomal proteins and 1 8S rRNA were modified. Ribosomal proteins cross-linked to pAUGU(n) der ivatives were identified earlier. In this paper, nucleotides G-1010, G -1029, G-1033, G-1051, G-1054 and G-1059 of 18S rRNA cross-linked to b oth pAUG and pAUGU(3) derivatives were identified by reverse transcrip tion analysis. (C) 1995 Elsevier Science B.V.