Engineering enzyme microenvironments for enhanced biocatalysis

Lancaster, Louis; Abdallah, Walaa; Banta, Scott; Wheeldon, Ian

doi:10.1039/c8cs00085a

Cited by 139 publications

(101 citation statements)

References 55 publications

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“…One objective of this work was to evaluate to which extent the hypothesis and main conclusions made on planar surfaces can be extended to porous carbon nanotube networks 15,45 . Local variation of pH occurs in the course of electrocatalysis, and the effect on enzyme conformation, stability or orientation in the immobilized state require in-depth investigations, using combination of techniques [46][47] . This will open avenues towards new material and architecture design to protect enzymes against local pH variation.…”

Section: Resultsmentioning

confidence: 99%

Electrostatic-Driven Activity, Loading, Dynamics, and Stability of a Redox Enzyme on Functionalized-Gold Electrodes for Bioelectrocatalysis

et al. 2018

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Oxygen reduction reaction is the limiting step in fuel cells, and many works are in progress to find efficient cathode catalysts. Among them, bilirubin oxidases are copper-based enzymes that reduce oxygen into water with low overpotentials. The factors that ensure electrocatalytic efficiency of the enzyme in the immobilized state are not well understood, however. In this work, we use a multiple methodological approach on a wide range of pH for protein adsorption and for electrocatalysis, to demonstrate the effect of electrostatic interactions on the electrical wiring, dynamics and stability of a bilirubin oxidase adsorbed on self-assembled-monolayers on gold. We show on one hand that the global charge of the enzyme controls the loading on the interface, and that the specific activity of the immobilized enzyme decreases with the enzyme coverage. On the other hand, we show that the dipole moment of the protein and the charge in the vicinity of the Cu site acting as the entry point of electrons, drive the enzyme orientation. In case of weak electrostatic interactions, we demonstrate that local pH variation affects the 2 electron transfer rate as a result of protein mobility on the surface. On the contrary, stronger electrostatic interactions destabilize the protein structure and affect the stability of the catalytic signal. These data illustrate the interplay between immobilized protein dynamics and local environment that control the efficiency of bioelectrocatalysis.

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Section: Resultsmentioning

confidence: 99%

Electrostatic-Driven Activity, Loading, Dynamics, and Stability of a Redox Enzyme on Functionalized-Gold Electrodes for Bioelectrocatalysis

et al. 2018

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“…Our approach is one of an increasing number of strategies designed to enhance enzyme catalysis by engineering the enzyme microenvironment (Lancaster, Abdallah, Banta, & Wheeldon, 2018). For example, a series of recent studies developed and optimized a PTE‐DNA‐Au nanoparticle system that enhances k cat by altering the reaction mechanism (Breger et al, 2015; Breger et al, 2017; Samanta et al, 2018).…”

Section: Resultsmentioning

confidence: 99%

Molecular binding scaffolds increase local substrate concentration enhancing the enzymatic hydrolysis of VX nerve agent

Lang

Hong

Baker

et al. 2020

Biotech & Bioengineering

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Kinetic enhancement of organophosphate hydrolysis is a long‐standing challenge in catalysis. For prophylactic treatment against organophosphate exposure, enzymatic hydrolysis needs to occur at high rates in the presence of low substrate concentrations and enzymatic activity should persist over days and weeks. Here, the conjugation of small DNA scaffolds was used to introduce substrate binding sites with micromolar affinity to VX, paraoxon, and methyl‐parathion in close proximity to the enzyme phosphotriesterase (PTE). The result was a decrease in KM and increase in the rate at low substrate concentrations. An optimized system for paraoxon hydrolysis decreased KM by 11‐fold, with a corresponding increase in second‐order rate constant. The initial rates of VX and methyl‐parathion hydrolysis were also increased by 3.1‐ and 6.7‐fold, respectively. The designed scaffolds not only increased the local substrate concentration, but they also resulted in increased stability and PTE‐DNA particle size tuning between 25 and ~150 nm. The scaffold engineering approach taken here is focused on altering the local chemical and physical microenvironment around the enzyme and is therefore compatible with active site engineering via combinatorial and computational approaches.

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“…The resultant hybrid organic−inorganic composite can thus be regarded as a model system for synthetic cavity-based heterogeneous electrocatalysts. Notably, a plethora of different research fields spanning from metal−organic frameworks 80,81 and covalent−organic frameworks 82 to molecular catalysis 83−86 and synthetic biology 87 are also heavily focused on tuning the local environment and coordination spheres around a catalytic active site. The development of such model systems and analytical methodology as presented here may help us to gain insight in this complex and important field of research.…”

Section: ■ Conclusionmentioning

confidence: 99%

1 Host-guest Chemistry Meets Electrocatalysis: Cucurbit[6]uril on a Au Surface as Hybrid System in CO2 Reduction

Wagner

Reisner

Heidary

et al. 2019

Proceedings of the nanoGe Fall Meeting 2019

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The rational control of forming and stabilizing reaction intermediates to guide specific reaction pathways remains to be a major challenge in electrocatalysis. In this work, we report a surface active-site engineering approach for modulating electrocatalytic CO 2 reduction using the macrocycle cucurbit[6]uril (CB[6]). A pristine gold surface functionalized with CB[6] nanocavities was studied as a hybrid organic−inorganic model system that utilizes host−guest chemistry to influence the heterogeneous electrocatalytic reaction. The combination of surface-enhanced infrared absorption (SEIRA) spectroscopy and electrocatalytic experiments in conjunction with theoretical calculations supports capture and reduction of CO 2 inside the hydrophobic cavity of CB[6] on the gold surface in aqueous KHCO 3 at negative potentials. SEIRA spectroscopic experiments show that the decoration of gold with the supramolecular host CB[6] leads to an increased local CO 2 concentration close to the metal interface. Electrocatalytic CO 2 reduction on a CB[6]-coated gold electrode indicates differences in the specific interactions between CO 2 reduction intermediates within and outside the CB[6] molecular cavity, illustrated by a decrease in current density from CO generation, but almost invariant H 2 production compared to unfunctionalized gold. The presented methodology and mechanistic insight can guide future design of molecularly engineered catalytic environments through interfacial host−guest chemistry.

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Engineering enzyme microenvironments for enhanced biocatalysis

Cited by 139 publications

References 55 publications

Electrostatic-Driven Activity, Loading, Dynamics, and Stability of a Redox Enzyme on Functionalized-Gold Electrodes for Bioelectrocatalysis

Electrostatic-Driven Activity, Loading, Dynamics, and Stability of a Redox Enzyme on Functionalized-Gold Electrodes for Bioelectrocatalysis

Molecular binding scaffolds increase local substrate concentration enhancing the enzymatic hydrolysis of VX nerve agent

1 Host-guest Chemistry Meets Electrocatalysis: Cucurbit[6]uril on a Au Surface as Hybrid System in CO2 Reduction

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