Intraresidual Correlated Motions in Peptide Chain
BastidaAdolfo
Carmona-GarcíaJavier
ZúñigaJosé
RequenaAlberto
CerezoJavier
2019
Conformational flexibility of polypeptide chains is mainly
driven by changes in the (phi, psi) dihedrals of each residue. Such motions, however,
are not completely independent, as certain (anti)correlated motions are
favored. In this work, we investigate the correlations between the dihedral
displacements of adjacent residues, (Δphi i, Δpsi i+1) and (Δphi i-1, Δpsi i), i.e. interresidual, and within the same residue, (Δphi i, Δpsi i), i.e. intraresidual, by analyzing extensive
Molecular Dynamics trajectories of initially extended polyalanine chains in
detail. Correlations are evaluated individually at different residue
conformations covering the whole (phi, psi)-space. From these we draw maps which clearly show
how the coupled motions strongly depend on the conformation, thus unveiling an
unprecedented strong intramolecular correlation displaying opposite
(correlated/anticorrelated) behaviors at different conformations. By developing
a tailored model, it is also demonstrated that both inter and intraresidual
correlations arise from the propensity of the peptide to minimize the overall
atomic displacements along the whole polypeptide chain.