Fig. 2. Computational nanomechanics characterization of SAP fibril seeds. The number of β-interactions refers to the number of β-contacts among (LDLK)3 moieties identified through Morphoscanner (see Section 1.7 of the ESI†). (a) UA-SMD maximum stress of axial stretching was equal to 323 MPa (ε = 52%; t = 128 ps; no of β-interactions = 6). GoMARTINI maximum stress was influenced by SS assignment: in the case of DSSP SS assignment, the maximum stress was equal to 310 MPa (ε = 28%; t = 175 ps; no of β-interactions = 6), whereas with extended SS parameters, it was equal to 236 MPa (ε = 36%; t = 92 ps; no of β-interactions = 6). (b) UA-SMD axial bending maximum stress was equal to 163 MPa (ε = 250%; t = 106 ps; no of β-interactions = 6). Again, maximum stress in GoMARTINI was heavily affected by SS parameters: i.e. it was 200 MPa (ε = 250%) and 150 MPa (ε = 1000%) for respectively DSSP-assigned and extended SS parameters. (c) UA-SMD axial stretching test highlighted the failure conformation and stress value for FAQ-(LDLK)3 at 281 MPa (ε = 50%). Such a conformation was similar to the one identified through GoMARTINI (σ = 400 MPa; ε = 75%). In the case of FAQ-(LDLK)3, DSSP assigned the extended SS parameters to the (LDLK)3 self-assembling backbone, whereas it assigned random coil SS parameters to residues comprising the functional motif. (d) UA-SMD axial bending maximum stress was equal to 160 MPa (ε = 50%). Instead, GoMARTINI maximum stress was 247 MPa (ε = 220%).
