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Hydration of peptides. I. Calculation of accessible surface areas for several conformations of a cyclic dipeptide

1980; Elsevier BV; Volume: 87; Issue: 1 Linguagem: Inglês

10.1016/0022-5193(80)90220-9

1095-8541

M. Genest, F. Vovelle, Marius Ptak, Bernard Maigret, S. Prémilat,

Crystallography and molecular interactions

Abstract The concept of “static accessibility” to water has been used to determine the accessible surface area of a cyclic dipeptide: c ( l -Thr- l -His). Different calculated and experimental conformations of this model molecule have been examined, which allows us to analyse the variations of accessibility of the hydration sites localized on the peptide backbone and on the polar side chains. The maximum solvation criterion involves a large destabilization of conformations governed by intramolecular interactions. The variations of the amphiphilic character with the conformations are relatively small. Nevertheless, the experimental conformation seems to reflect such a behaviour, especially in the crystal, in which the amphiphilic character is compatible with intermolecular interactions. The accessibility studies must be regarded only as a preliminary step to a more quantitative analysis of peptide hydration.