Open AccessThe Effect of a Cytidine‐to‐Uridine Transition on the Stability of Escherichia coli A19 5‐S RNA
Author(s) -
DIGWEED Martin,
KUMAGAI Izumi,
PIELER Tomas,
ERDMANN Volker A.
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb06904.x
Subject(s) - rna , ribosomal rna , cytidine , escherichia coli , uridine , chemistry , gel electrophoresis , protein subunit , nuclease , base pair , protein secondary structure , biochemistry , dna , biology , microbiology and biotechnology , enzyme , gene
We have been able to isolate several species of 5‐S ribosomal RNA from Escherichia coli A19. These molecules were separated on the basis of their differing stabilities during electrophoresis on 12% polyacrylamide gels in 7 M urea. This differing stability is shown, in one case, to be due to a different primary sequence. We have determined the sequence of the least stable of these molecules and have found only one difference to the published sequence of E. coli A19 5‐S RNA, namely a uridine in place of a cytidine at position 92. The consequent G · U base pair, formed in a normally highly stable G · C‐rich region, is responsible for a drastic reduction in the stability of the molecule. This instability leads to a less constrained, more compact molecule which thus migrates faster in electrophoresis under denaturing conditions. This species of 5‐S RNA is shown to make up 30% of the total 5‐S RNA in the 50‐S ribosomal subunits in this organism. Further structural studies were carried out using S1 nuclease digestion, sodium bisulphite modification and thermal melting analysis. All these methods indicate a 5‐S RNA drastically destabilized in parts of its secondary and tertiary structure. Finally, the ability of the variant 5‐S RNA to recognize and form a complex with its 50‐S subunit binding proteins was examined and found to be impaired.