Rational
design of peptides has become a powerful tool
to produce
self-assembled nanostructures with the ability to catalyze different
chemical reactions, paving the way to develop minimalistic enzyme-like
nanomaterials. Catalytic amyloid-like assemblies have emerged among
the most versatile and active, but they often require additional factors
for activity. Elucidating how these factors influence the structure
and activity is key for the design. Here, we showed that biologically
relevant metal ions can guide and modulate the self-assembly of a
small peptide into diverse amyloid architectures. The morphology and
catalytic activity of the resulting fibrils were tuned by the specific
metal ion decorating the surface, whereas X-ray structural analysis
of the amyloids showed ion-dependent shape sizes. Molecular dynamics
simulations showed that the metals can strongly affect the local conformational
space, which can trigger major rearrangements of the fibrils. Our
results demonstrate that the conformational landscape of catalytic
amyloids is broad and tunable by external factors, which can be critical
for future design strategies.