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Computational estimation of specific side chain interaction energies in α helices
Author(s) -
Fisinger Samo,
Serrano Luis,
Lacroix Emmanuel
Publication year - 2001
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.34901
Subject(s) - side chain , pairwise comparison , chain (unit) , protein design , amino acid , protein structure , chemistry , biological system , physics , statistical physics , computational chemistry , computer science , biology , artificial intelligence , nuclear magnetic resonance , biochemistry , quantum mechanics , polymer
We have used a structure energy‐based computer program developed for protein design, Perla, to provide theoretical estimates of all specific side chain–side chain interaction energies occurring in α helices. The computed side chain–side chain interaction energies were used as substitutes for the corresponding values used by the helix/coil transition algorithm, AGADIR. Predictions of peptide helical contents were nearly as successful as those obtained with the originally calibrated set of parameters; a correlation to experimentally observed α‐helical populations of 0.91 proved that our theoretical estimates are reasonably correct for amino acid pairs that are frequent in our database of peptides. Furthermore, we have determined experimentally the previously uncharacterized interaction energies for Lys–Ile, Thr–Ile, and Phe–Ile amino acid pairs at i,i + 4 positions. The experimental values compare favorably with the computed theoretical estimates. Importantly, the computed values for Thr–Ile and Phe–Ile interactions are better than the energies based on chemical similarity, whereas for Lys–Ile they are similar. Thus, computational techniques can be used to provide precise energies for amino acid pairwise interactions, a fact that supports the development of structure energy–based computational tools for structure predictions and sequence design.