Estabilización molecular del comportamiento de los lipoplejos aniónicos mediante las fuerzas de Martini

Abstract

This degree work aimed to study and stabilise the molecular behaviour of the anionic lipoplex. The molecular simulation was performed with Martini coarse-grained (CG) aided by Visual Molecular Dynamics (VMD) and GROningen MAchine for Chemical Simulations (GROMACS). A box of 120x120x200 Angstroms was constructed, containing the cylinder representing the deoxyribonucleic acid (DNA) and the plane giving rise to the membrane with the lipid 1,2-dioleoyl-sn-glycero-3-phospho-L-serine sodium (DOPS), these were exposed in a primitive 1:1 model. The dielectric constant of the system was 15, the pressure 1 bar and its temperature 303 K; because DNA, DOPS lipid, membrane and salt ions (NaCl) are charged, charge-size correlation phenomena arise, i.e. they interact with each other by the effect of their charges. In the initial configuration, solvation, minimisation, and energy balance were practised, then values were added and changed in the variables to obtain the different systems. The distance values were 0, 15 and 3.5 nm in systems 1, 2 and 3 respectively. It was concluded that the addition of NaCl in one of them, managed to stabilise it at a certain point and to counteract the electrostatic interactions, the formalism of Ewald sums was used. This result is also due to the electric double layer model because the surface charge density increased, and the system became overcharged. With this, the cations and anions changed their behaviour, causing them to be attracted and giving rise to electrostatic interactions. The total energy value of the system was -5.62030e+05 kJ/mol, in your time of 1040.577 s. It is recommended to extend the investigation with a larger system for the study of DNA lipoflexion.