Edward Pimentel

All Publications

• Hyper-Expandable Cross-Linked Protein Crystals as Scaffolds for Catalytic Reactions ACS APPLIED MATERIALS & INTERFACES Chung, J. S., Hartman, E. M., Mertick-Sykes, E. J., Pimentel, E. B., Martell, J. D. 2024; 17 (1): 311-321

  Abstract

  Scaffolding catalytic reactions within porous materials is a powerful strategy to enhance the reaction rates of multicatalytic systems. However, it remains challenging to develop materials with high porosity, high diversity of functional groups within the pores, and guest-adaptive tunability. Furthermore, it is challenging to capture large catalysts such as enzymes within porous materials. Protein-based materials are promising candidates to overcome these limitations, owing to their large pore sizes and potential for stimuli-responsive adaptability. In this work, hydrogel beads were generated from cross-linked lysozyme crystals. These swellable lysozyme cross-linked crystals (SLCCs) expand more than 10 mL per gram of crystal following a simple treatment in ethanol, followed by the addition of water. SLCCs are sensitive to the solution environment and change their extent of swelling from adjusting the concentration and identity of the ions in the solution, or by changing the flexibility of the protein backbone, such as adding dithiothreitol to reduce the protein disulfide bonds. SLCCs can adsorb a wide range of catalysts ranging from transition metal complexes to large biomacromolecules, such as the 160 kDa enzyme glucose oxidase (GOx). Transition metal catalysts and enzymes captured within SLCCs maintained their catalytic activity and exhibited minimal leaching. We performed a cascade reaction by adsorbing GOx and the transition metal catalyst Fe-TAML into SLCCs, resulting in enhanced activity compared to a free-floating reaction. SLCCs offer a promising combination of attributes as scaffolds for multicatalytic reactions, including gram-scale batch preparation, tunable expansion to greater than 20-fold in volume, guest-responsive adaptable behavior, and facile capture of a wide array of small molecule and enzyme-catalysts.

  View details for DOI 10.1021/acsami.4c15051

  View details for Web of Science ID 001381626700001

  View details for PubMedID 39701958

• The 235-360 GHz Rotational Spectrum of 1-Oxaspiro[2.5]octa-4,7-dien-6-one─Analysis of the Ground Vibrational State and Its 10 Lowest-Energy Vibrationally Excited States. The journal of physical chemistry. A Esselman, B. J., Pimentel, E. B., Styers, W. H., Jean, D. R., Woods, R. C., McMahon, R. J. 2024; 128 (1): 191-203

  Abstract

  The millimeter-wave rotational spectrum of 1-oxaspiro[2.5]octa-4,7-dien-6-one (1) was collected from 235 to 360 GHz. With the rotational spectrum of this compound available for the first time, more than 5500 a- and c-type transitions were observed and assigned for the vibrational ground state. These transitions were least-squares fit to S- and A-reduced, sextic distorted-rotor Hamiltonians in the Ir representation (σfit = 37 kHz). Additionally, transitions of four fundamental states (ν22, ν21, ν39, and ν38), four overtone states (2ν22, 3ν22, 4ν22, and 5ν22), and two combination states (ν22 + ν21 and ν22 + ν39) were measured, assigned, and least-squares fit to single-state, S- and A-reduced, sextic distorted-rotor Hamiltonians in the Ir representation (σfit < 42 kHz). The computed vibration-rotation interaction constants (B0 - Bv) (MP2 and B3LYP/6-311+G(2d,p)) were compared to their corresponding experimental values, showing excellent agreement for all fundamental states. Based on the intensities of the transitions from six members of the v ν22 series, the fundamental frequency of ν22 was determined to be 79.0 (2.1) cm-1.

  View details for DOI 10.1021/acs.jpca.3c07049

  View details for PubMedID 38153243

• DNA-Compatible Copper/TEMPO Oxidation for DNA-Encoded Libraries. Bioconjugate chemistry Merrifield, J. L., Pimentel, E. B., Peters-Clarke, T. M., Nesbitt, D. J., Coon, J. J., Martell, J. D. 2023; 34 (8): 1380-1386

  Abstract

  Aldehydes are important synthons for DNA-encoded library (DEL) construction, but the development of a DNA-compatible method for the oxidation of alcohols to aldehydes remains a significant challenge in the field of DEL chemistry. We report that a copper/TEMPO catalyst system enables the solution-phase DNA-compatible oxidation of DNA-linked primary activated alcohols to aldehydes. The semiaqueous, room-temperature reaction conditions afford oxidation of benzylic, heterobenzylic, and allylic alcohols in high yield, with DNA compatibility verified by mass spectrometry, qPCR, Sanger sequencing, and ligation assays. Subsequent transformations of the resulting aldehydes demonstrate the potential of this method for robust library diversification.

  View details for DOI 10.1021/acs.bioconjchem.3c00254

  View details for PubMedID 37540561

  View details for PubMedCentralID PMC10831869

• DNA-Scaffolded Synergistic Catalysis. Journal of the American Chemical Society Pimentel, E. B., Peters-Clarke, T. M., Coon, J. J., Martell, J. D. 2021; 143 (50): 21402-21409

  Abstract

  We report DNA-scaffolded synergistic catalysis, a concept that combines the diverse reaction scope of synergistic catalysis with the ability of DNA to precisely preorganize abiotic groups and undergo stimuli-triggered conformational changes. As an initial demonstration of this concept, we focus on Cu-TEMPO-catalyzed aerobic alcohol oxidation, using DNA as a scaffold to hold a copper cocatalyst and an organic radical cocatalyst (TEMPO) in proximity. The DNA-scaffolded catalyst maintained a high turnover number upon dilution and exhibited 190-fold improvement in catalyst turnover number relative to the unscaffolded cocatalysts. By incorporating the cocatalysts into a DNA hairpin-containing scaffold, we demonstrate that the rate of the synergistic catalytic reaction can be controlled through a reversible DNA conformational change that alters the distance between the cocatalysts. This work demonstrates the compatibility of synergistic catalytic reactions with DNA scaffolding, opening future avenues in reaction discovery, sensing, responsive materials, and chemical biology.

  View details for DOI 10.1021/jacs.1c10757

  View details for PubMedID 34898209

  View details for PubMedCentralID PMC9101022