Identification and Sequence Analysis of Contact Sites between Ribosomal Proteins and rRNA in Escherichia coli 30 S Subunits by a New Approach Using Matrix-assisted Laser Desorption/Ionization-Mass Spectrometry Combined with N-terminal Microsequencing (1997)

Cross-linked peptide-oligoribonucleotide complexes derived from distinct regions of the rRNA and individual ribosomal proteins of the 30 S ribosomal subunits fromEscherichia coli were isolated and purified. Cross-linking sites at the amino acid and nucleotide level were determined by N-terminal amino acid sequence analysis in combination with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). MALDI-MS analysis performed subsequent to a partial alkaline hydrolysis of cross-linked peptide-oligoribonucleotide complexes allowed for the first time the cross-linked rRNA moiety to be sequenced by this technique. In this manner Lys-44 in S4 was determined to be cross-linked to the oligoribonucleotide at positions 1531–1542 on the 16 S RNA (whereby either U-1541 or A-1542 is the actual cross-link site), Lys-75 in S7 to positions 1374–1379 (C-1378 cross-linked), Met-114 in S7 to 1234–1241 (U-1240 cross-linked), Lys-55 in S8 to 651–654 (U-653 cross-linked), and Lys-29 in S17 to 629–633 (U-632 cross-linked). The novel approach applied here promises to be useful for similar studies on other known protein·RNA complexes. Cross-linked peptide-oligoribonucleotide complexes derived from distinct regions of the rRNA and individual ribosomal proteins of the 30 S ribosomal subunits fromEscherichia coli were isolated and purified. Cross-linking sites at the amino acid and nucleotide level were determined by N-terminal amino acid sequence analysis in combination with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). MALDI-MS analysis performed subsequent to a partial alkaline hydrolysis of cross-linked peptide-oligoribonucleotide complexes allowed for the first time the cross-linked rRNA moiety to be sequenced by this technique. In this manner Lys-44 in S4 was determined to be cross-linked to the oligoribonucleotide at positions 1531–1542 on the 16 S RNA (whereby either U-1541 or A-1542 is the actual cross-link site), Lys-75 in S7 to positions 1374–1379 (C-1378 cross-linked), Met-114 in S7 to 1234–1241 (U-1240 cross-linked), Lys-55 in S8 to 651–654 (U-653 cross-linked), and Lys-29 in S17 to 629–633 (U-632 cross-linked). The novel approach applied here promises to be useful for similar studies on other known protein·RNA complexes. The quarternary structure of the ribosome from the eubacteriumEscherichia coli has been studied intensively for many years, and several individual models concerning either the protein composition and the arrangement of proteins (e.g. Refs.1Wittmann-Liebold B. Köpke A.K.E. Arndt E. Krömer W. Hatakeyama T. Wittmann H.G. Hill W.E. Dahlberg A. Garret R.A. Moore P.B Schlessinger D. Warner J.R. The Ribosome: Structure, Function and Evolution. American Society for Microbiology, Washington, D. C.1990: 598-616Google Scholar, 2Traut R.R. Tewari D.S. Sommer A. Gavino G.R. Olson H.M. Glitz D. Hardesty B. Kramer G. Structure, Function and Genetics of Ribosomes. Springer-Verlag, Berlin1986: 286-308Google Scholar, 3Capel M.S. Engelman D.M. Freeborn B.R. Kjeldgaard M. Moore Scholar, D. M. G. Scholar, M. G. Hill W.E. Dahlberg A. Garret R.A. Moore P.B Schlessinger D. Warner J.R. The Ribosome: Structure, Function and Evolution. American Society for Microbiology, Washington, D. C.1990: or the of 16 S RNA the (e.g. A. T. G. Hill W.E. Dahlberg A. Garret R.A. Moore P.B Schlessinger D. Warner J.R. The Ribosome: Structure, Function and Evolution. American Society for Microbiology, Washington, D. C.1990: Scholar, T. Scholar, A. Scholar, been the of models at the level is the sites proteins and proteins and rRNA known at the amino acid level with a of cross-linked protein (e.g. G. Scholar, B. Scholar, B. a of protein sites been at the nucleotide level studies at the level B. in combination with of isolated ribosomal proteins (e.g. Scholar, Scholar, Scholar, the and the of the rRNA in ribosomal has to the of several proteins the 30 S G. A. A. T. R.R. B. Scholar, RNA regions of individual ribosomal proteins in to the rRNA been B. the analysis of the sites on the rRNA has a of ribosomal of and sites at the amino acid and nucleotide the of the of ribosomal proteins be models of the and models be to the of the ribosome derived from A. M. M. T. M. this a approach to the sites at the at the nucleotide level cross-linked peptide-oligoribonucleotide complexes isolated from ribosomal The is on N-terminal sequence analysis with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). laser S ribosomal from E. from M. has been applied for the of and Scholar, G. A. Scholar, of MALDI-MS for of (e.g. B. D. Scholar, Scholar, B. B. M. E. and of (e.g. E. A. M. and been for the first time the of by MALDI-MS cross-linked to The applied here be a for in in other protein·RNA of 30 S ribosomal subunits from E. of ribosomal subunits with and of cross-linked were performed to B. rRNA derived from cross-linked ribosomal subunits with and B. was to a with or of the cross-linked peptide-oligoribonucleotide complexes was by B. at and were and cross-linked peptide-oligoribonucleotide complexes were with of in the of of and of for at at at for at the was in and protein and were in the in B. a with for and for with at and were and cross-linked complexes were in for studies and at of the cross-linked to of cross-linked peptide-oligoribonucleotide in acid was sequenced in a protein The was for with the known E. coli protein by the A. of cross-linked peptide-oligoribonucleotide complexes were in the of a time of with a laser to B. B. M. E. The was and the were either in the or in the by laser mass of cross-linked a in acid of cross-linked peptide-oligoribonucleotide and of of acid in were on the and the was with by E. M. for 30 at were for of the was with the of the cross-linked were determined from the mass of by the alkaline hydrolysis of the cross-linked was by of with at for at The was and in of were were in of and with by E. A. M. and by mass analysis were and sequence the cross-linked to in 30 S ribosomal applied similar studies MALDI-MS been on cross-linked complexes sequence novel for and of peptide-oligoribonucleotide complexes derived from cross-linked ribosomal subunits was to the of from ribosomal proteins cross-linked either to the 16 S or the S RNA B. in this the sites the the cross-linked be subsequent to the rRNA to cross-linked complexes in to be to and by N-terminal amino acid and were to the cross-linked oligoribonucleotide moiety distinct regions of the ribosomal proteins and S17 from E. the sites be at the acid the and the oligoribonucleotide by the to a of complexes be by MALDI-MS for by acid a B. B. M. E. MALDI-MS has the of to the B. B. M. E. Scholar, E. A. M. Scholar, G.R. D.M. and of to the cross-linked complexes be by MALDI-MS partial hydrolysis with or with mass of and with or protein mass In a of with the of the or mass of the with of is a known from MALDI-MS analysis of E. M. In the of the complexes derived from ribosomal proteins S7 cross-linked to Lys-75 cross-linked to and S4 cross-linked to U-1541 or the mass of cross-linked be determined to E. M. mass of the complexes was the were with G.R. D.M. The nucleotide of the cross-linked complexes were from the mass the sequenced in the of the S7 cross-linked Met-114 to the 16 S and the mass of the complexes. with to the and were to the mass of the the be in the of the mass has a in with the the composition of cross-linked oligoribonucleotide moiety was for of the positions in the 16 S the mass a partial alkaline hydrolysis of the complexes by MALDI-MS analysis to sequence of the cross-linked oligoribonucleotide for a of the positions in the 16 S this Met-114 in S7 cross-linked to on the 16 S by determined Met-114 to be cross-linked to the oligoribonucleotide for S7 and the 16 S were to a cross-linked peptide-oligoribonucleotide in Lys-75 in S7 was cross-linked to in the 16 S been cross-linked with in studies to the S7 protein of the cross-linked The sites in S7 and were cross-linked to and with the of in in and here and in the the of The sites to the cross-linked oligoribonucleotide regions 1234–1241 and and the of S7 to the S4 sites cross-linked to the 16 S RNA been the with cross-linked B. and with Lys-44 cross-linked MALDI-MS analysis of the partial alkaline hydrolysis of the cross-linked peptide-oligoribonucleotide sequence of the cross-linked oligoribonucleotide The to Lys-44 in S4 was to be the of the 16 S Cross-linking studies with a B. M. G. studies with T. and or G. A. A. T. R.R. B. Scholar, T. RNA of S4 with of and of the 16 S the of a has been by the of derived from ribosomal proteins of cross-linked to the 16 S RNA B. the of the 16 S is known to be is to the ribosomal protein analysis of the S17 of the 16 S RNA to be to be cross-linked to Lys-29 in positions or The of was to be either or to the of the with studies on the 16 S of the 16 S RNA 629–633 is cross-linked to Lys-29 in the was to be cross-linked with to the S17 protein A. B. G. studies with B. M. G. and T. to of the 16 S RNA a to In the structure of S17 from regions and were to with the the 16 S RNA in the cross-linked in B. to B. with the of on the 16 S RNA for a of and in the 16 S RNA the S8 the sequence of the cross-linked oligoribonucleotide moiety be determined to be or with either or to the the actual cross-linked of with derived from T. Scholar, B. M. G. cross-linked studies at the rRNA level and studies with S8 R.A. Scholar, M. E. B. either positions or 651–654 the cross-linked in the 16 S RNA to Lys-55 in regions or to and the is in with to be cross-linked to the S8 protein is the is cross-linked to Lys-55 in the structure of S8 has been The cross-linked amino acid (whereby Lys-55 in E. to in B. is a structure of the protein has been to be of a RNA in S8 with the S17 the cross-linked nucleotide in the S8 and to a of the 16 S RNA ribosomal proteins with or the rRNA for in B. Scholar, B. M. A. similar to other complexes (e.g. be regions to the by the to The of regions in proteins S8 and S17 with is with a of proteins in the 30 S M.S. Engelman D.M. Freeborn B.R. Kjeldgaard M. Moore The here be useful in combination with the of ribosomal proteins S8 and S17 and the models of the 16 S RNA and the 30 S ribosomal A. M. M. T. M. for a S RNA The quarternary structure of the ribosome from the eubacteriumEscherichia coli has been studied intensively for many years, and several individual models concerning either the protein composition and the arrangement of proteins (e.g. Refs.1Wittmann-Liebold B. Köpke A.K.E. Arndt E. Krömer W. Hatakeyama T. Wittmann H.G. Hill W.E. Dahlberg A. Garret R.A. Moore P.B Schlessinger D. Warner J.R. The Ribosome: Structure, Function and Evolution. American Society for Microbiology, Washington, D. C.1990: 598-616Google Scholar, 2Traut R.R. Tewari D.S. Sommer A. Gavino G.R. Olson H.M. Glitz D. Hardesty B. Kramer G. Structure, Function and Genetics of Ribosomes. Springer-Verlag, Berlin1986: 286-308Google Scholar, 3Capel M.S. Engelman D.M. Freeborn B.R. Kjeldgaard M. Moore Scholar, D. M. G. Scholar, M. G. Hill W.E. Dahlberg A. Garret R.A. Moore P.B Schlessinger D. Warner J.R. The Ribosome: Structure, Function and Evolution. American Society for Microbiology, Washington, D. C.1990: or the of 16 S RNA the (e.g. A. T. G. Hill W.E. Dahlberg A. Garret R.A. Moore P.B Schlessinger D. Warner J.R. The Ribosome: Structure, Function and Evolution. American Society for Microbiology, Washington, D. C.1990: Scholar, T. Scholar, A. Scholar, been the of models at the level is the sites proteins and proteins and rRNA known at the amino acid level with a of cross-linked protein (e.g. G. Scholar, B. Scholar, B. a of protein sites been at the nucleotide level studies at the level B. in combination with of isolated ribosomal proteins (e.g. Scholar, Scholar, Scholar, the and the of the rRNA in ribosomal has to the of several proteins the 30 S G. A. A. T. R.R. B. Scholar, RNA regions of individual ribosomal proteins in to the rRNA been B. the analysis of the sites on the rRNA has a of ribosomal of and sites at the amino acid and nucleotide the of the of ribosomal proteins be models of the and models be to the of the ribosome derived from A. M. M. T. M. this a approach to the sites at the at the nucleotide level cross-linked peptide-oligoribonucleotide complexes isolated from ribosomal The is on N-terminal sequence analysis with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). laser S ribosomal from E. from matrix-assisted laser spectrometry 30 S ribosomal from E. coli from MALDI-MS M. has been applied for the of and Scholar, G. A. Scholar, of MALDI-MS for of (e.g. B. D. Scholar, Scholar, B. B. M. E. and of (e.g. E. A. M. and been for the first time the of by MALDI-MS cross-linked to The applied here be a for in in other protein·RNA complexes. of 30 S ribosomal subunits from E. of ribosomal subunits with and of cross-linked were performed to B. rRNA derived from cross-linked ribosomal subunits with and B. was to a with or of the cross-linked peptide-oligoribonucleotide complexes was by B. at and were and cross-linked peptide-oligoribonucleotide complexes were with of in the of of and of for at at at for at the was in and protein and were in the in B. a with for and for with at and were and cross-linked complexes were in for studies and at of the cross-linked to of cross-linked peptide-oligoribonucleotide in acid was sequenced in a protein The was for with the known E. coli protein by the A. of cross-linked peptide-oligoribonucleotide complexes were in the of a time of with a laser to B. B. M. E. The was and the were either in the or in the by laser mass of cross-linked a in acid of cross-linked peptide-oligoribonucleotide and of of acid in were on the and the was with by E. M. for 30 at were for of the was with the of the cross-linked were determined from the mass of by the alkaline hydrolysis of the cross-linked was by of with at for at The was and in of were were in of and with by E. A. M. and by mass analysis were of 30 S ribosomal subunits from E. of ribosomal subunits with and of cross-linked were performed to B. rRNA derived from cross-linked ribosomal subunits with and B. was to a with or of the cross-linked peptide-oligoribonucleotide complexes was by B. at and were and cross-linked peptide-oligoribonucleotide complexes were with of in the of of and of for at at at for at the was in and protein and were in the in B. a with for and for with at and were and cross-linked complexes were in for studies and at of the cross-linked to of cross-linked peptide-oligoribonucleotide in acid was sequenced in a protein The was for with the known E. coli protein by the A. of cross-linked peptide-oligoribonucleotide complexes were in the of a time of with a laser to B. B. M. E. The was and the were either in the or in the by laser mass of cross-linked a in acid of cross-linked peptide-oligoribonucleotide and of of acid in were on the and the was with by E. M. for 30 at were for of the was with the of the cross-linked were determined from the mass of by the alkaline hydrolysis of the cross-linked was by of with at for at The was and in of were were in of and with by E. A. M. and by mass analysis were rRNA derived from cross-linked ribosomal subunits with and B. was to a with or of the cross-linked peptide-oligoribonucleotide complexes was by B. at and were and cross-linked peptide-oligoribonucleotide complexes were with of in the of of and of for at at at for at the was in and protein and were in the in B. a with for and for with at and were and cross-linked complexes were in for studies and at of the cross-linked to of cross-linked peptide-oligoribonucleotide in acid was sequenced in a protein The was for with the known E. coli protein by the A. of cross-linked peptide-oligoribonucleotide complexes were in the of a time of with a laser to B. B. M. E. The was and the were either in the or in the by laser mass of cross-linked a in acid of cross-linked peptide-oligoribonucleotide and of of acid in were on the and the was with by E. M. for 30 at were for of the was with the of the cross-linked were determined from the mass of by the alkaline hydrolysis of the cross-linked was by of with at for at The was and in of were were in of and with by E. A. M. and by mass analysis were rRNA derived from cross-linked ribosomal subunits with and B. was to a with or of the cross-linked peptide-oligoribonucleotide complexes was by B. at and were and cross-linked peptide-oligoribonucleotide complexes were with of in the of of and of for at at at for at the was in and protein and were in the in B. a with for and for with at and were and cross-linked complexes were in for studies and at The rRNA derived from cross-linked ribosomal subunits with and B. was to a with or of the cross-linked peptide-oligoribonucleotide complexes was by B. at and were and cross-linked peptide-oligoribonucleotide complexes were with of in the of of and of for at at at for at the was in and protein and were in the in B. a with for and for with at and were and cross-linked complexes were in for studies and at N-terminal of the cross-linked to of cross-linked peptide-oligoribonucleotide in acid was sequenced in a protein The was for with the known E. coli protein by the A. of the cross-linked to of cross-linked peptide-oligoribonucleotide in acid was sequenced in a protein The was for with the known E. coli protein by the A. of cross-linked peptide-oligoribonucleotide complexes were in the of a time of with a laser to B. B. M. E. The was and the were either in the or in the by laser mass of cross-linked a in acid of cross-linked peptide-oligoribonucleotide and of of acid in were on the and the was with by E. M. for 30 at were for of the was with the of the cross-linked were determined from the mass of by the alkaline hydrolysis of the cross-linked was by of with at for at The was and in of were were in of and with by E. A. M. and by mass analysis were of cross-linked peptide-oligoribonucleotide complexes were in the of a time of with a laser to B. B. M. E. The was and the were either in the or in the by laser mass of cross-linked a in acid of cross-linked peptide-oligoribonucleotide and of of acid in were on the and the was with by E. M. for 30 at were for of the was with the of the cross-linked were determined from the mass of by the alkaline hydrolysis of the cross-linked was by of with at for at The was and in of were were in of and with by E. A. M. and by mass analysis were and sequence the cross-linked to in 30 S ribosomal applied similar studies MALDI-MS been on cross-linked complexes sequence novel for and of peptide-oligoribonucleotide complexes derived from cross-linked ribosomal subunits was to the of from ribosomal proteins cross-linked either to the 16 S or the S RNA B. in this the sites the the cross-linked be subsequent to the rRNA to cross-linked complexes in to be to and by N-terminal amino acid and were to the cross-linked oligoribonucleotide moiety distinct regions of the ribosomal proteins and S17 from E. the sites be at the acid the and the oligoribonucleotide by the to a of complexes be by MALDI-MS for by acid a B. B. M. E. MALDI-MS has the of to the B. B. M. E. Scholar, E. A. M. Scholar, G.R. D.M. and of to the cross-linked complexes be by MALDI-MS partial hydrolysis with or with mass of and with or protein mass In a of with the of the or mass of the with of is a known from MALDI-MS analysis of E. M. In the of the complexes derived from ribosomal proteins S7 cross-linked to Lys-75 cross-linked to and S4 cross-linked to U-1541 or the mass of cross-linked be determined to E. M. mass of the complexes was the were with G.R. D.M. The nucleotide of the cross-linked complexes were from the mass the sequenced in the of the S7 cross-linked Met-114 to the 16 S and the mass of the complexes. with to the and were to the mass of the the be in the of the mass has a in with the the composition of cross-linked oligoribonucleotide moiety was for of the positions in the 16 S the mass a partial alkaline hydrolysis of the complexes by MALDI-MS analysis to sequence of the cross-linked oligoribonucleotide for a of the positions in the 16 S this Met-114 in S7 cross-linked to on the 16 S by determined Met-114 to be cross-linked to the oligoribonucleotide for S7 and the 16 S were to a cross-linked peptide-oligoribonucleotide in Lys-75 in S7 was cross-linked to in the 16 S been cross-linked with in studies to the S7 protein of the cross-linked The sites in S7 and were cross-linked to and with the of in in and here and in the the of The sites to the cross-linked oligoribonucleotide regions 1234–1241 and and the of S7 to the S4 sites cross-linked to the 16 S RNA been the with cross-linked B. and with Lys-44 cross-linked MALDI-MS analysis of the partial alkaline hydrolysis of the cross-linked peptide-oligoribonucleotide sequence of the cross-linked oligoribonucleotide The to Lys-44 in S4 was to be the of the 16 S Cross-linking studies with a B. M. G. studies with T. and or G. A. A. T. R.R. B. Scholar, T. RNA of S4 with of and of the 16 S the of a has been by the of derived from ribosomal proteins of cross-linked to the 16 S RNA B. the of the 16 S is known to be is to the ribosomal protein analysis of the S17 of the 16 S RNA to be to be cross-linked to Lys-29 in positions or The of was to be either or to the of the with studies on the 16 S of the 16 S RNA 629–633 is cross-linked to Lys-29 in the was to be cross-linked with to the S17 protein A. B. G. studies with B. M. G. and T. to of the 16 S RNA a to In the structure of S17 from regions and were to with the the 16 S RNA in the cross-linked in B. to B. with the of on the 16 S RNA for a of and in the 16 S RNA the S8 the sequence of the cross-linked oligoribonucleotide moiety be determined to be or with either or to the the actual cross-linked of with derived from T. Scholar, B. M. G. cross-linked studies at the rRNA level and studies with S8 R.A. Scholar, M. E. B. either positions or 651–654 the cross-linked in the 16 S RNA to Lys-55 in regions or to and the is in with to be cross-linked to the S8 protein is the is cross-linked to Lys-55 in the structure of S8 has been The cross-linked amino acid (whereby Lys-55 in E. to in B. is a structure of the protein has been to be of a RNA in S8 with the S17 the cross-linked nucleotide in the S8 and to a of the 16 S RNA ribosomal proteins with or the rRNA for in B. Scholar, B. M. A. similar to other complexes (e.g. be regions to the by the to The of regions in proteins S8 and S17 with is with a of proteins in the 30 S M.S. Engelman D.M. Freeborn B.R. Kjeldgaard M. Moore The here be useful in combination with the of ribosomal proteins S8 and S17 and the models of the 16 S RNA and the 30 S ribosomal A. M. M. T. M. for a S RNA and sequence the cross-linked to in 30 S ribosomal applied similar studies MALDI-MS been on cross-linked complexes sequence novel for and of peptide-oligoribonucleotide complexes derived from cross-linked ribosomal subunits was to the of from ribosomal proteins cross-linked either to the 16 S or the S RNA B. in this the sites the the cross-linked be subsequent to the rRNA to cross-linked complexes in to be to and by N-terminal amino acid and were to the cross-linked oligoribonucleotide moiety distinct regions of the ribosomal proteins and S17 from E. the sites be at the acid The the and the oligoribonucleotide by the to a of complexes be by MALDI-MS for by acid a B. B. M. E. MALDI-MS has the of to the B. B. M. E. Scholar, E. A. M. Scholar, G.R. D.M. and of to the cross-linked complexes be by MALDI-MS partial hydrolysis with or with mass of and with or protein mass In a of with the of the or mass of the with of is a known from MALDI-MS analysis of E. M. In the of the complexes derived from ribosomal proteins S7 cross-linked to Lys-75 cross-linked to and S4 cross-linked to U-1541 or the mass of cross-linked be determined to E. M. mass of the complexes was the were with G.R. D.M. The nucleotide of the cross-linked complexes were from the mass the sequenced in the of the S7 cross-linked Met-114 to the 16 S and the mass of the complexes. with to the and were to the mass of the the be in the of the mass has a in with the the composition of cross-linked oligoribonucleotide moiety was for of the positions in the 16 S the mass a partial alkaline hydrolysis of the complexes by MALDI-MS analysis to sequence of the cross-linked oligoribonucleotide for a of the positions in the 16 S this Met-114 in S7 cross-linked to on the 16 S by determined Met-114 to be cross-linked to the oligoribonucleotide for S7 and the 16 S were to a cross-linked peptide-oligoribonucleotide in Lys-75 in S7 was cross-linked to in the 16 S been cross-linked with in studies to the S7 protein of the cross-linked The sites in S7 and were cross-linked to and with the of in in and here and in the the of The sites to the cross-linked oligoribonucleotide regions 1234–1241 and and the of S7 to the In S4 sites cross-linked to the 16 S RNA been the with cross-linked B. and with Lys-44 cross-linked MALDI-MS analysis of the partial alkaline hydrolysis of the cross-linked peptide-oligoribonucleotide sequence of the cross-linked oligoribonucleotide The to Lys-44 in S4 was to be the of the 16 S Cross-linking studies with a B. M. G. studies with T. and or G. A. A. T. R.R. B. Scholar, T. RNA of S4 with of and of the 16 S the of a has been by the of derived from ribosomal proteins of cross-linked to the 16 S RNA B. the of the 16 S is known to be is to the ribosomal protein MALDI-MS analysis of the S17 of the 16 S RNA to be to be cross-linked to Lys-29 in positions or The of was to be either or to the of the with studies on the 16 S of the 16 S RNA 629–633 is cross-linked to Lys-29 in the was to be cross-linked with to the S17 protein A. B. G. studies with B. M. G. and T. to of the 16 S RNA a to In the structure of S17 from regions and were to with the the 16 S RNA in the cross-linked in B. to B. with the of on the 16 S RNA for a of and in the 16 S RNA the S8 the sequence of the cross-linked oligoribonucleotide moiety be determined to be or with either or to the the actual cross-linked of with derived from T. Scholar, B. M. G. cross-linked studies at the rRNA level and studies with S8 R.A. Scholar, M. E. B. either positions or 651–654 the cross-linked in the 16 S RNA to Lys-55 in regions or to and the is in with to be cross-linked to the S8 protein is the is cross-linked to Lys-55 in the structure of S8 has been The cross-linked amino acid (whereby Lys-55 in E. to in B. is a structure of the protein has been to be of a RNA in S8 with the S17 the cross-linked nucleotide in the S8 and to a of the 16 S RNA ribosomal proteins with or the rRNA for in B. Scholar, B. M. A. similar to other complexes (e.g. be regions to the by the to The of regions in proteins S8 and S17 with is with a of proteins in the 30 S M.S. Engelman D.M. Freeborn B.R. Kjeldgaard M. Moore The here be useful in combination with the of ribosomal proteins S8 and S17 and the models of the 16 S RNA and the 30 S ribosomal A. M. M. T. M. for a S RNA to W. for the S8 and for