Molecular dynamics simulations of a coarse-grained, embedded-charge model of lysozyme aqueous solutions are compared with small-angle neutron scattering experiments. Measures concern different solutions with a 10% by weight protein concentration and an increasing pH in the range 2–6. The model is based on a soft-core modification of the original Carlsson–Malmsten–Linse model, where in particular all residues carrying an appreciable amount of residual charge, as a function of the pH, are explicitly taken into account in the overall macromolecular interaction. Simulations reproduce qualitatively the experimental trend of the structure factor such as, in particular, the observed change from a low-pH regime, dominated by repulsive interactions, to behaviour mainly determined by attractive forces, at higher pH. Possible improvements of the model, towards a better reproduction of the structural properties of the real solution, are proposed.
Molecular dynamics and small-angle neutron scattering of lysozyme aqueous solutions
ABRAMO, Maria Concetta;CACCAMO, Carlo;CALVO, Massimo Rosario;Conti Nibali, V.;COSTA, Dino;GIORDANO, Rita;PELLICANE, Giuseppe;WANDERLINGH, Ulderico
2011-01-01
Abstract
Molecular dynamics simulations of a coarse-grained, embedded-charge model of lysozyme aqueous solutions are compared with small-angle neutron scattering experiments. Measures concern different solutions with a 10% by weight protein concentration and an increasing pH in the range 2–6. The model is based on a soft-core modification of the original Carlsson–Malmsten–Linse model, where in particular all residues carrying an appreciable amount of residual charge, as a function of the pH, are explicitly taken into account in the overall macromolecular interaction. Simulations reproduce qualitatively the experimental trend of the structure factor such as, in particular, the observed change from a low-pH regime, dominated by repulsive interactions, to behaviour mainly determined by attractive forces, at higher pH. Possible improvements of the model, towards a better reproduction of the structural properties of the real solution, are proposed.Pubblicazioni consigliate
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