Thermodynamics of transfer ribonucleic acids: The effect of sodium on the thermal unfolding of yeast tRNAPhe

Ernesto Freire, Rodney L. Biltonen

Research output: Contribution to journalArticle

Abstract

The thermal unfolding of yeast phenylalanine‐specific tRNA (tRNAPhe) has been calorimetrically investigated at several salt concentrations in the absence of magnesium. Application of the deconvolution theory of macromolecular conformational transitions allows calculation of the thermodynamic parameters of unfolding. It is demonstrated that the unfolding of tRNAPhe occurs in a sequential fashion and that four separate transitions or five macromolecular thermodynamic states exist in the temperature range 8–72°C under the experimental conditions of these studies (0.067–0.52M Na+). The enthalpy and entropy changes between states and the relative population of each state as a function of temperature and salt concentration have been obtained. Sodium stabilizes the low‐temperature conformations of tRNAPhe. The increase in the melting temperatures of each transition is shown to be linearly dependent on the logarithm of sodium concentration. These results allow calculation of the “phase” diagram for the transitions as a function of salt concentration.

Original languageEnglish (US)
Pages (from-to)1257-1272
Number of pages16
JournalBiopolymers
Volume17
Issue number5
DOIs
StatePublished - May 1978

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Biomaterials
  • Organic Chemistry

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