Hydrodynamic changes accompanying the thermal denaturation of transfer ribonucleic acid.

Abstract

Sedimentation velocity, viscosity, density, and ultraviolet absorbance properties of yeast transfer RNA in dilute neutral salt solution have been studied over a wide temperature range. In this way it has been possible to follow thermally induced changes in both secondary structure and over-all shape of transfer of RNA. The results show that the denaturation of transfer RNA involves more than the loss of secondary structure. Thus, the highly ordered, compact, and symmetric structure, stable at 20[degree], undergoes, between 20 and 40[degree], a major shape change involving loss of asymmetry and molecular expansion with relatively little loss of secondary structure before commencing the major phase of the helix-coil transition above 50. Below 15, the data indicate a tendency for sRNA to aggregate.