Three-helix-bundle Protein in a Ramachandran Model

Abstract

We study the thermodynamic behavior of a model protein with 54 amino acids that forms a three-helix bundle in its native state. The model contains three types of amino acids and five to six atoms per amino acid and has the Ramachandran torsional angles ${\varphi }_i$, ${\psi }_i$ as its degrees of freedom. The force field is based on hydrogen bonds and effective hydrophobicity forces. For a suitable choice of the relative strength of these interactions, we find that the three-helix-bundle protein undergoes an abrupt folding transition from an expanded state to the native state. Also shown is that the corresponding one- and two-helix segments are less stable than the three-helix sequence.

15 pages, 7 figures

References in corpus (1)

• Linking Rates of Folding in Lattice Models of Proteins with Underlying Thermodynamic Characteristics

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