Vibrons in alpha-helix proteins: influence of the inhomegenous mass distribution in the amino acid sequenceReport as inadecuate




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1 LPM - Laboratoire de Physique Moléculaire

Abstract : The influence of the inhomogeneous mass distribution in the amino acid sequence on the amide-I vibrons in protein is addressed within the small polaron approach. It is shown that inhomogeneities in the sequence favor a randomness in the polaron Hamiltonian via the dressing mechanism. The polaron dynamics is thus described by a 1D tight binding model with correlated off-diagonal disorder. At low temperature, the polaron hopping constants exhibit small fluctuations around a rather large average value so that the polaron Hamiltonian appears weakly disordered. Extended states occur over a wide range of energies around the band center whereas the states close to the band edges appear localized. By contrast, at biological temperature, a stronger disorder takes place which originates in a drastic decrease of the average hopping constant. The number of localized states increases but few states close to the band center exhibit a localization length about to or greater than the lattice size. The extended nature of the states at the band center is attributed to the existence of short range correlations in the random hopping constants.

keyword : protein vibration phonon polaron disorder localization





Author: Vincent Pouthier -

Source: https://hal.archives-ouvertes.fr/



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