title: Precise localization of the site of cross-linking between protein L4 and 23S ribonucleic acid induced by mild ultraviolet irradiation of Escherichia coli 50S ribosomal subunits.
abstract: Mild ultraviolet irradiation of Escherichia coli 50S ribosomal subunits causes a cross-linking reaction between protein and RNA, whose primary target is protein L4 [Möller, K., & Brimacombe, R. (1975) Mol. Gen. Genet. 141, 343]. Here we have determined the site of this cross-link both on L4 and on 23S RNA. For the site on the protein, a cross-linked protein-oligonucleotide complex was isolated and subjected to successive digestions with various proteases. In each case the peptide-oligonucleotide complexes formed were analyzed. It could clearly be shown that the cross-link site was contained within a characteristic peptide 16--20 amino acids long and that the amino acid concerned was the tyrosine residue at position 35 in the recently completed L4 sequence (M. Kimura and B. Wittmann-Liebold, personal communication). For the site on the RNA, a cross-linked L4--23S RNA complex was subjected to mild nuclease digestion, producing a range of L4--RNA fragments which were isolated with the help of a new two-dimensional gel electrophoresis system. Oligonucleotide analyses of these fragments, combined with successive nuclease digestions of the residual oligonucleotide attached to protein L4, established that the site of cross-linking was homogeneous, involving a uridine residue at position 615 in the recently determined 23S RNA sequence [Brosius, J., Dull, T. J., & Noller, H. F. (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 201].
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000528:radiation effects*; D046911:Macromolecular Substances; D009698:Nucleoproteins / Q000528:radiation effects*; D009843:Oligoribonucleotides / Q000032:analysis; D010446:Peptide Fragments / Q000032:analysis; D010447:Peptide Hydrolases; D011485:Protein Binding; D012335:RNA, Ribosomal / Q000528:radiation effects*; D012261:Ribonucleoproteins / Q000528:radiation effects*; D012269:Ribosomal Proteins / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D046911:Macromolecular Substances; D009698:Nucleoproteins; D009843:Oligoribonucleotides; D010446:Peptide Fragments; D012335:RNA, Ribosomal; D012261:Ribonucleoproteins; D012269:Ribosomal Proteins; D010447:Peptide Hydrolases