Fig. 6. Control over the fibrillization yield by varying the oligomeric nucleation propensities of surfactant-like peptides.

a Potential of mean force (PMF) profiles of fibril (left) and oligomer (right) models along the reaction coordinate r derived from steered MD (SMD) simulations provides information on the thermodynamic stability of fibril and oligomer structures. Increasing the number of charges of the headgroups reduced structural stability of the fibrils, however, not in the oligomers. A representative SMD trajectory, during which an SLP monomer is dragged from the core of oligomer and fibril model for 90 Å along r, is shown under each graph. b Graphical representation of the proposed mechanism leading to the different yields of nanofibers between SLP1 and SLP4. The size distribution of the oligomeric intermediates is controlled by the number of headgroup charges, which the less charged SLPs form bigger-sized oligomer (two on the left) and the more charged SLPs form smaller-sized oligomers (two on the right). Between the SLPs with the same charges, the fibrillization propensity is modulated by the β-sheet propensities of the tail group, with the SLP of higher β-sheet propensities giving higher yields of fibrils, i.e., SLP1 > 2 and SLP3 > 4.