Due to the associated computational efforts, simulations of atomistic structures were not considered in the present study. Especially, considering the system sizes (320 macromolecules each) and the equilibration time of such structures, particularly at lower water contents , modeling at an atomistic resolution becomes unfeasible. The relatively high number of molecules was used to achieve a higher degree of heterogeneity, reflecting an important property of SOM. However, given the size of the systems and the simulation of several microseconds, the densities could be obtained relatively easily using the coarse-grained approach.