AbstractThe structure of yeast tRNAAspin aqueous solutions has been analyzed in the light of results obtained from Raman spectra recorded at from 5 to 82°C and compared to those of tRNAPhe. Firm evidence is given of a reversible conformation transition for tRNAAspat 20°C. This transition is observed for the first time in the tRNA series. The low‐temperature conformation appears to have a more regular ribose–phosphate backbone and a more effective G base‐stacking. This conformational change, which occurs essentially in the D loop, could be connected to the existence of two (A and B) crystal forms obtained depending on crystallization conditions. The melting temperatures, which are different for each base stacking in tRNAAsp, lie in a range of about 70°C, much higher than for tRNAPhe. This fact is interpreted by a higher ratio of G‐C base pairs