RNA-protein cross-linking inEscherichia coli30S ribosomal subunits; determination of sites on 16S RNA that are cross-linked to proteins S3, S4, S5, S7, S8, S9, S11, S13, S19 and S21 by treatment with methyl p-azidophenyl acetimidate

Abstract

RNA-protein cross-links were introduced into E. coli 30S ribosomal subunits by treatment with methyl p-azidophenyl acet-imidate. After partial nuclease digestion of the RNA moiety, a number of cross-linked RNA-protein complexes were isolated by a new three-step procedure. Protein and RNA analysis of the individual complexes gave the following results: Proteins S3, S4, S5 and S8 are cross-linked to the 5'-terminal tetranucleotide of 16S RNA. S5 is also cross-linked to the 16S RNA within an oligonucle-otide encompassing positions 559–561. Proteins S11, S9, S19 and S7 are cross-linked to 16S RNA within oligonucleotides encompassing positions 702–705, 1130–1131, 1223–1231 and 1238–1240, respectively. Protein S13 is cross-linked to an oligonucleotide encompassing positions 1337–1338, and is also involved in an anomalous cross-link within positions 189–191. Protein S21 is cross-linked to the 3'-terminal dodecanucleotide of the 16S RNA.