59
Viktor Stein (ed.), Synthetic Protein Switches: Methods and Protocols, Methods in Molecular Biology, vol. 1596,
DOI 10.1007/978-1-4939-6940-1_4, © Springer Science+Business Media LLC 2017
Chapter 4
Catalytic Amyloid Fibrils That Bind Copper
to Activate Oxygen
Alex Sternisha and Olga Makhlynets
Abstract
Amyloid-like fibrils assembled from de novo designed peptides lock ligands in a conformation optimal for
metal binding and catalysis in a manner similar to how metalloenzymes provide proper coordination environment through fold. These supramolecular assemblies efficiently catalyze p-nitrophenyl ester hydrolysis
in the presence of zinc and phenol oxidation by dioxygen in the presence of copper. The resulting heterogeneous catalysts are inherently switchable, as addition and removal of the metal ions turns the catalytic
activity on and off, respectively. The ease of peptide preparation and self-assembly makes amyloid-like
fibrils an attractive platform for developing catalysts for a broad range of chemical reactions. Here, we present
a detailed protocol for the preparation of copper-containing fibrils and for kinetic characterization of their
abilities to oxidize phenols.
Key words Peptides, Fibrils, Catalysis, Dioxygen activation, Phenol oxidation
1 Introduction
Metalloenzymes utilize metal ions to catalyze some of the most
challenging chemical reactions, such as methane oxidation, lignin
degradation, and nitrogen fixation [1–5]. Even more impressive is
the fact that metalloenzymes are capable of performing these reactions in a very selective and stereospecific manner. The high efficiency and selectivity of natural metalloenzymes has inspired much
effort to (re)design catalytic metalloproteins to improve selectivity
for a substrate of choice and to catalyze novel chemical transformations [6]. Many of the current state-of-the-art catalyst design strategies take advantage of both existing and de novo designed proteins
to optimize the metal coordination sphere and to provide a binding site for the substrate. Recently, this approach was taken to the
next level by employing self-assembly of short peptides into fibrils.
The fibrils provide stability and the appropriate coordination
sphere for the metal ions necessary to facilitate chemical transformations [7–9]. Amyloid-like fibrils, assembled from short
Viktor Stein (ed.), Synthetic Protein Switches: Methods and Protocols, Methods in Molecular Biology, vol. 1596,
DOI 10.1007/978-1-4939-6940-1_4, © Springer Science+Business Media LLC 2017
Chapter 4
Catalytic Amyloid Fibrils That Bind Copper
to Activate Oxygen
Alex Sternisha and Olga Makhlynets
Abstract
Amyloid-like fibrils assembled from de novo designed peptides lock ligands in a conformation optimal for
metal binding and catalysis in a manner similar to how metalloenzymes provide proper coordination environment through fold. These supramolecular assemblies efficiently catalyze p-nitrophenyl ester hydrolysis
in the presence of zinc and phenol oxidation by dioxygen in the presence of copper. The resulting heterogeneous catalysts are inherently switchable, as addition and removal of the metal ions turns the catalytic
activity on and off, respectively. The ease of peptide preparation and self-assembly makes amyloid-like
fibrils an attractive platform for developing catalysts for a broad range of chemical reactions. Here, we present
a detailed protocol for the preparation of copper-containing fibrils and for kinetic characterization of their
abilities to oxidize phenols.
Key words Peptides, Fibrils, Catalysis, Dioxygen activation, Phenol oxidation
1 Introduction
Metalloenzymes utilize metal ions to catalyze some of the most
challenging chemical reactions, such as methane oxidation, lignin
degradation, and nitrogen fixation [1–5]. Even more impressive is
the fact that metalloenzymes are capable of performing these reactions in a very selective and stereospecific manner. The high efficiency and selectivity of natural metalloenzymes has inspired much
effort to (re)design catalytic metalloproteins to improve selectivity
for a substrate of choice and to catalyze novel chemical transformations [6]. Many of the current state-of-the-art catalyst design strategies take advantage of both existing and de novo designed proteins
to optimize the metal coordination sphere and to provide a binding site for the substrate. Recently, this approach was taken to the
next level by employing self-assembly of short peptides into fibrils.
The fibrils provide stability and the appropriate coordination
sphere for the metal ions necessary to facilitate chemical transformations [7–9]. Amyloid-like fibrils, assembled from short