Search PubMed⌕ Search

Biomedical subjects

C Zwieb

Publications and source records attributed to C Zwieb.

77 records · Page 5Linked to original sources
PubMed1980

Localisation of a series of intra-RNA cross-links in 16S RNA, induced by ultraviolet irradiation of Escherichia coli 30S ribosomal subunits.

Mild ultraviolet irradiation of E. coli ribosomal subunits leads to the formation of a number of intra-RNA cross-links, in addition to the RNA-protein cross-links already reported (see refs. 9, 10). After partial ribonuclease digestion of the RNA from irradiated subunits, complexes containing these intra-RNA cross-links can be isolated on a two-dimensional gel electrophoresis system, and subjected to sequence analysis. A series of these cross-linked complexes is described, and the cross-linked RNA regions are compared with the secondary structures derived for 16S RNA (see refs. 6, 7).

Base Sequence↗
PubMed1979

Max-Planck-Institut für Molekulare Genetik, Abteilung Wittmann, Berlin-Dahlem, GFR.

It is well established that when E. coli 30S ribosomal subunits are irradiated with ultraviolet light under mild conditions a specific cross-link is formed between protein S7 and the 16S RNA. Methodology is presented for the analysis of the single nucleotide residue concerned in this cross-link. Firstly, the identity of the ribonuclease T1 octanucleotide attached to S7 is confirmed by a new method, which involves isolation and analysis of S7-polynucleotide complexes containing 30 -- 40 nucleotides. Secondly, the isolated S7-octanucleotide complex is digested successively with ribonuclease A, proteinase K and ribonuclease T2, and the nucleotides liberated are identified. The results show unambiguously that uridine residue number 1239 in the 16S RNA sequence is cross-linked to protein S7.

Base Sequence↗
PubMed1978

RNA-protein cross-linking in Eschericia coli 30S ribosomal subunits: a method for the direct analysis of the RNA regions involved in the cross-links.

A prerequisite for topographical studies on ribosomal subunits involving RNA-protein cross-linking is that the cross-linking sites on the RNA should be determined. Methodology is presented which offers a solution to this problem, using as a test system 30S subunits in which protein S7 has been cross-linked to the 16S RNA by ultraviolet irradiation. The method is based on a gel separation system in the presence of a non-ionic detergent. When a ribonucleoprotein fragment containing RNA-protein cross-links is applied to this system, non-cross-linked protein is removed, and simultaneously the cross-linked RNA-protein complex is separated from non-cross-linked RNA. Oligonucleotide analysis of the S7-RNA complex isolated in this manner showed it to consist of a region of RNA from sections P-A of the 16S RNA. A single characteristic oligonucleotide was absent from this region, and it was tentatively concluded that this missing oligonucleotide contains the actual site of cross-linking.

Bacterial Proteins↗
PubMed1978

Evidence for RNA-RNA cross-link formation in Escherichia coli ribosomes.

Evidence is presented in three separate cases for the formation of RNA-RNA cross-links in intact E. coli ribosomes and ribosomal subunits. The first case is a cross-link between the 18S and 13S regions of the 23S RNA, induced by ultraviolet irradiation. The second is a cross-link at the subunit interface, generated by the bifunctional reagent bis-(2-chloroethyl)-amine. The third example is a cross-link between sections O'-D and P-A of the 16S RNA, induced as in the first case by ultraviolet irradiation. The RNA-RNA cross-links can be identified as such, despite the complications introduced by concomitant RNA-protein cross-linking reactions. The experiments represent a first attempt to introduce RNA-RNA cross-linking into studies of the topographical organization of the RNA within the ribosome.

Escherichia coli↗