Nucleic Acids Research, 1982, Vol. 10, No. 6 1995-2006
© 1982
MOLECULAR BIOLOGY |
A ribonucleoprotein fragment of the 30 S ribosome of E. coli: evidence for long range RNA-RNA interactions
Biochemistry Department, The Weizmann Institute of Science Rehovot 76100, Israel
Received December 21, 1981. Revised March 4, 1982. Accepted March 4, 1982.
A stable homogeneous ribonucleoprotein fragment of the 30 S ribosomal subunit of E. coli has been prepared by mild nuclease digestion and heating in a constant ionic environment. The fragment contains about half of the 16 S ribosomal RNA and six proteins: S4, S7, S9, S13, S16 and S19. The RNA moiety contains the reported binding sites of all six proteins. After deproteinization, 80% of the RNA migrated as two major electrophoretic bands, which were isolated and sequenced. Each band contained sequences from the 5' and 3' thirds of the 16 S RNA but none from the central third. That these two noncontiguous RNA domains migrated together electrophoretically in Mg++-containing gels after deproteinization constitutes direct evidence that the 16 S RNA is folded in the intact ribosome so as to bring the two domains close together and that there are RNA-RNA interactions between them in the presence of Mg++.