Enthalpy of helix-coil transition: missing link in rationalizing the thermodynamics of helix-forming propensities of the amino acid residues.

ABSTRACT: It is known that different amino acid residues have effects on the thermodynamic stability of an alpha-helix. The underlying mechanism for the thermodynamic helical propensity is not well understood. The major accepted hypothesis is the difference in the side-chain configurational entropy loss upon helix formation. However, the changes in the side-chain configurational entropy explain only part of the thermodynamic helical propensity, thus implying that there must be a difference in the enthalpy of helix-coil transition for different residues. This work provides an experimental test to this hypothesis. Direct calorimetric measurements of folding of a model host peptide in which the helix formation is induced by metal binding is applied to a wide range of residue types, both naturally occur

SUBMITTER: Richardson JM 

PROVIDER: S-EPMC547846 | biostudies-literature | 2005 Feb

REPOSITORIES: biostudies-literature