Protein L24, from the Escherichia coli ribosome, protects a large region of 23S RNA against ribonuclease digestion. This protected RNA consists of a series of non-contiguous subfragments encompassing about 480 nucleotides at the 5' -end of 23S RNA (1). The present work demonstrates that this RNA moiety remains intact, after removal of protein L24, indicating that the subfragments are maintained together by RNA-RNA interactions. Using a urea washing procedure, the weakly bound RNA subfragments were selectively removed leaving more strongly interacting subfragments that were identified, by gel electrophoresis and oligonucleotide fingerprinting, and shown to derive from widely separated sequence regions. VSports手机版.