Sequence-Dependent Structure/Function Relationships of Catalytic Peptide-Enabled Gold Nanoparticles Generated under Ambient Synthetic Conditions

Abstract

Peptide-enabled nanoparticle (NP) synthesis routes can create and/or assemble functional nanomaterials under environmentally friendly conditions, with properties dictated by complex interactions at the biotic/abiotic interface. Manipulation of this interface through sequence modification can provide the capability for material properties to be tailored to create enhanced materials for energy, catalysis, and sensing applications. Fully realizing the potential of these materials requires a comprehensive understanding of sequence-dependent structure/function relationships that is presently lacking. In this work, the atomic-scale structures of a series of peptide-capped Au NPs are determined using a combination of atomic pair distribution function analysis of high-energy X-ray diffraction data and advanced molecular dynamics (MD) simulations. The Au NPs produced with different peptide sequences exhibit varying degrees of catalytic activity for the exemplar reaction 4-nitrophenol reduction. The experimentally derived atomic-scale NP configurations reveal sequence-dependent differences in structural order at the NP surface. Replica exchange with solute-tempering MD simulations are then used to predict the morphology of the peptide overlayer on these Au NPs and identify factors determining the structure/catalytic properties relationship. We show that the amount of exposed Au surface, the underlying surface structural disorder, and the interaction strength of the peptide with the Au surface all influence catalytic performance. A simplified computational prediction of catalytic performance is developed that can potentially serve as a screening tool for future studies. Our approach provides a platform for broadening the analysis of catalytic peptide-enabled metallic NP systems, potentially allowing for the development of rational design rules for property enhancement.

Peptide-Directed Assembly of Single-Helical Gold Nanoparticle Superstructures Exhibiting Intense Chiroptical Activity

“…In addition, methionine residues, which also bind strongly, could contribute to the overall binding interaction. 40 The inner surface of the helical ribbon is sterically hindered, which prevents particle binding.…”

Peptide-templated noble metal catalysts: syntheses and applications

“…89 This speculation of the relationship between the peptide sequence and catalytic activity of Au catalysts was later confirmed by molecular dynamic (MD) simulations. 90 After studying the influence of peptide sequences on the activity of Au catalysts, the role of reducing agents was discussed. 91 When using weak reductants like ascorbic acid, large and globular Au NPs with rough surfaces are fabricated.…”

Peptide-Directed PdAu Nanoscale Surface Segregation: Toward Controlled Bimetallic Architecture for Catalytic Materials

“…[21][22][23] Such observations suggest bio-inspired routes can be used to optimize catalytic properties for bimetallic systems, but can only be fully realized if sequencedependent structure/function relationships are better understood. We have recently reported on developing such relationships using atomic-scale structural methods for peptide-capped monometallic catalysts, 24,25 wherein the presence of strongly-adsorbing residues in the peptide sequence drive formation of disordered catalytic surfaces. Such strategies for monometallic systems are likely adaptable to bimetallic nanoparticles, while also providing a means to modulate surface composition through complex interactions at the biotic/abiotic interface.…”