Molecular dynamics and small-angle neutron scattering of lysozyme aqueous solutions

Maria Concetta Abramo (1) , Carlo Caccamo (1) , Massimo Calvo (2) , Valeria Conti Nibali (3) , Dino Costa (1) , Rita Giordano (3) , Giuseppe Pellicane (4) , Romina Ruberto (1) , Ulderico Wanderlingh (3)

1 Fisica
2 Dip. di Fisica
3 Physics
4 School of Physics

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 and Linse model [J. Phys. Chem. B 105 (2001) p.9040], where in particular all residues carrying an appreciable amount of residual charge, as a function of the pH, are explicitly taken into account into the overall macromolecular interaction. Simulations reproduce qualitatively the experimental trend of the structure factor as, in particular, the observed change from a low-pH regime, dominated by repulsive interactions, to a behaviour mainly determined by attractive forces, at higher pH. Possible improvements of the model, toward a better reproduction of the structural properties of the real solution are proposed.

Mots clés: Physical Sciences

Domaines: Matière Condensée [cond-mat]

Maria Concetta Abramo, Carlo Caccamo, Massimo Calvo, Valeria Conti Nibali, Dino Costa, et al.. Molecular dynamics and small-angle neutron scattering of lysozyme aqueous solutions. Philosophical Magazine, 2011, 91 (13-15), pp.2066-2076. ⟨10.1080/14786435.2011.559485⟩. ⟨hal-00686170⟩