Fig. 3. Computational nanomechanics characterization of the (LDLK)3 fibril. The number of β-interactions refers to the number of β-contacts detected among (LDLK)3 backbones. (a) UA-SMD axial stretching failure stress was 146 MPa. In GoMARTINI, the maximum stress was influenced by SS parameter assignments: (b) in the case of DSSP-derived SS parameters, the maximum stress was equal to 206 MPa, (c) whereas with extended SS parameters, it was 305 MPa. (d) UA-SMD axial bending failure stress was equal to 195 MPa. As expected, in GoMARTINI, the maximum stress was again heavily affected by SS assignment: (e) with DSSP it was equal to 306 MPa, (f) while with extended SS parameters it was 280 MPa. In the detected failure conformations in UA-SMD simulations, fibrils display multiple rupture points; this may be due to the enhanced stability of β-sheet structures when modeled with the Gromos force field. This was also demonstrated through Morphoscanner analysis (see Section 1.7 of the ESI for details†), which identified the same number of β-interactions throughout UA-SMD simulations. This feature was not reflected in GO-SMD simulations. Indeed, Morphoscanner identified small variations in the number of β-interactions.
