Open AccessRibosomal proteins S7 and L1 are located close to the decoding site ofE.coliribosome — affinity labeling studies with modified tRNAs carrying photoreactive probes attached adjacent to the 3′-end of the anticodon
Author(s) -
Jan Podkowiński,
Piotr Górnicki
Publication year - 1989
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/17.21.8767
Subject(s) - ribosome , transfer rna , biology , ribosomal protein , ribosomal rna , biochemistry , a site , p site , translation (biology) , escherichia coli , binding site , covalent bond , microbiology and biotechnology , rna , biophysics , chemistry , messenger rna , organic chemistry , gene
Two photoreactive azidonitrophenyl probes have been attached to Yeast methionine elongator tRNA by chemical modification of the N6-(threoninocarbonyl)adenosine located next to the 3'-end of the anticodon. The maximum distance between the purine ring and the azido group estimated for the two probes is 16-17 and 23-24A, respectively. Binding and cross-linking of the uncharged, modified tRNAs to E. coli ribosomes have been studied with and without poly(A,U,G) as a message, under conditions directing uncharged tRNAs preferentially to the P-site. The modified tRNAs retain their binding activity and upon irradiation bind covalently to the ribosome with very high yields. Protein S7 is the major cross-linking target for both modified tRNAs, in the presence or absence of poly(A,U,G). Protein L1 and to a lesser extent proteins L33 and L27 have been found to be cross-linked with the short probe. Cross-linking to 168 rRNA reaches significant levels only in the absence of the message.