Identification of single-stranded regions in Torulopsis utilis 5S RNA was attempted by the use of Nuclease S1, a single-strand specific endonuclease. When T. utilis 5S RNA was subjected to prolonged incubation with Nuclease S1, about 50% of the substrate 5S RNA remained as large oligonucleotide "cores." Such Nuclease S1-resistant fragments were purified and sequenced by column chromatographic procedures. These analyses revealed that regions around positions 12, 40, 57, and 110 are in exposed single-stranded loops at 37 degrees C and that regions around positions 12 and 40 are most exposed at 20 degrees C. These results are compatible with our secondary structure model for T. utilis 5S RNA (Nishikawa & Takemura (1974) J. Biochem. 76, 935-947) except that the 5' part of the molecule (from the region around position 22 to that around position 57) might have a somewhat looser conformation than our secondary structure model suggests. The implications of such results are also discussed in relation to the presumed function of the sequence C-G-A-U-C (around position 40) as one of the recognition sites for initiator tRNA binding on ribosomes.
No takes yet. Share an insight, caveat, or question.
Nishikawa et al. (1977) studied this question.