Laser Raman evidence for new cloverleaf secondary structures for eukaryotic 5.8S RNA and prokaryotic 5S RNA.

Neither of the two previously proposed secondary structures for eukaryotic 5.8S RNA is consistent with the present laser Raman results. A new, highly stable "cloverleaf" secondary structure not only fits the Raman data but also accounts for previously determined enzymatic partial cleavage patterns, base sequence and pairing homologies, and G-C and A-U base pair numbers and ratios. The new cloverleaf model also conserves several structural features (constant loops, bulges, and stems) consistent with known 5.8S RNA functions. Finally, we propose a similar new cloverleaf secondary structure for Escherichia coli 5S RNA, consonant with many known properties of prokaryotic 5S RNA.