Simulation of multicomponent biomolecular systems frequently requires the combination of parameters for different subsystems. For example, to study biomineralization processes, one needs to accurately describe the interactions between very different species in solution as well as with a (growing) mineral phase. The combination of forcefields is an inherently difficult problem – especially in the case of a combination of solution- and solid-phase components (e.g. ions in solution and in the mineral), since different approximations are made during the parametrization of the subsystems.<br/>Forcefield combination implies that parameters are not used exactly at the state point or system composition they were derived at, thus conceptually linking the forecfield-combination challenge to the phenomenon of limited transferability that is most prominently discussed in the field of coarse grained simulations. Here, “transferability” refers to the problem that model parameters are strictly-speaking only valid at the state point and system composition where they had been derived. The applicability to other state points/systems cannot be taken for granted and must be carefully assessed. Similarly, one finds that simulation models do not necessarily “represent” all physical-chemical properties of the system of interest equally well – a consequence of resolution reduction such as the neglect of electronic polarization in atomistic forcefields or the omission of atomistic dregrees of freedom in coarse grained models. Typically, transferability and representability problems increase with decreasing level of resolution, i.e. the coarser a model, the more limited is its applicabilty range. Consequently, these issues have been recognized as a particularly relevant challenge for coarse grained models. But the solution strategies developed there may very well benefit other areas such as classical atomistic forcefieds for multicomponent or multiphase biomolecular systems.<br/>Transferability and representability challenges are encountered almost everywhere in atomistic and coarse grained simulations of biomolecular systems, examples ranging from environment-induced conformational transitions to phase separation processes and interface systems. In this talk different examples and solution strategies will be discussed.

Transferability challenges in atomistic and coarse grained biomolecular simulation

251st National Meeting (2016)

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