34 / 92
- 33 -
Polymers and Self Assembly: From Biology to Nanomaterials
Wednesday Speaker Abstracts
Short Peptides Self-Assemble in the Presence of Metals to Produce Catalytic Nanomaterials
Caroline Rufo
1
, Yurii Moroz
1
, Olga Makhlynets
1
, Jan Stoehr
2
, Jenny Hu
2
, William DeGrado
2
,
Ivan Korendovych
1
.
1
Syracuse University, Syracuse, USA,
2
UCSF, San Francisco, CA, USA.
Enzymes fold into unique three-dimensional structures, which underlie their remarkable catalytic
properties. The requirement that they be stably folded is a likely factor that contributes to their
relatively large size (> 10,000 Dalton). However, much shorter peptides can achieve well-
defined conformations through the formation of amyloid fibrils. To test whether short amyloid-
forming peptides might in fact be capable of enzyme-like catalysis, we designed a series of 7-
residue peptides that act as Zn
2+
-dependent esterases. Zn
2+
helps stabilize the fibril formation,
while also acting as a cofactor to catalyze acyl ester hydrolysis. The fibril activity is on par with
the most active to date zinc-protein complex. Such remarkable efficiency is due to the small size
of the active unit (likely a dimer of 7-residue peptides), while the protein is at least 15-fold larger
in molecular weight. The observed catalytic activity is not limited to ester hydrolysis. We have
designed copper binding peptides that are capable oxygen activation.
These results indicate that prion-like fibrils are able to not only catalyze their own formation –
they also can catalyze chemical reactions. Thus, they might have served as intermediates in the
evolution of modern-day metalloenzymes. These results also have implications for the design of
self-assembling nanostructured catalysts including ones containing a variety of biological and
nonbiological metal ions.