Abstract
We have recently shown that 16S RNA can be extracted from 30S ribosomes by an acetic acid-urea precipitation procedure which yields RNA capable of binding 13 individual ribosomal proteins. This is in contrast to phenol extracted 16S RNA which can specifically associate with only 7 proteins2-7. In the experiments reported here, we demonstrate that the difference in protein binding capacities is due to a relatiely more "open" configuration possessed by the acetic acid-urea 16S RNA. Under identical conditions, acetic acid-urea 16S RNA is more susceptible to limited T1-RNase digestion than is phenol-16S RNA. In addition, acetic acid-urea RNA shows a relatively slower electrophoretic mobility. The observable difference in conformation between the two types of RNA is lost by storage at-70 degrees C. This loss is accompanied by a reduction in protein binding capacity of the acetic acid-urea 16S RNA.