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

• Published in: Philosophical magazine (2003. Print) 2011-05, Vol.91 (13-15), p.2066-2076
• Main Authors: Abramo, M.C., Caccamo, C., Calvo, M., Conti Nibali, V., Costa, D., Giordano, R., Pellicane, G., Ruberto, R., Wanderlingh, U.
• Format: Article
• Language: English
• Subjects: Aqueous solutions; coarse-grained models; Computer simulation; Condensed Matter; Condensed matter: structure, mechanical and thermal properties; Crystalline state (including molecular motions in solids); Current carriers; Exact sciences and technology; Lysozyme; Mathematical models; Molecular dynamics; Neutron diffraction and scattering; Neutron scattering; Neutron scattering techniques (including small-angle scattering); Physics; proteins; SANS; Structure of solids and liquids; crystallography; Theory of crystal structure, crystal symmetry; calculations and modeling
• ISSN: 1478-6435; 1478-6443; 1478-6433
• DOI: 10.1080/14786435.2011.559485

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.