Self‐Assembled Peptide Nano‐Superstructure towards Enzyme Mimicking Hydrolysis

Computation-Driven Rational Design of Self-Assembled Short Peptides for Catalytic Hydrogen Production

Self-assembling peptides represent a captivating area of study in nanotechnology and biomaterials. This interest is largely driven by their unique properties and the vast application potential across various fields such as catalytic functions. However, design complexities, including high-dimensional sequence space and structural diversity, pose significant challenges in the study of such systems. In this work, we explored the possibility of self-assembled peptides to catalyze the hydrolysis of hydrosilane for hydrogen production using ab initio calculations and carried out wet-lab experiments to confirm the feasibility of these catalytic reactions under ambient conditions. Further, we delved into the nuanced interplay between sequence, structural conformation, and catalytic activity by combining modeling with experimental techniques such as transmission electron microscopy and nuclear magnetic resonance and proposed a dual mode of the microstructure of the catalytic center. Our results reveal that although research in this area is still at an early stage, the development of self-assembled peptide catalysts for hydrogen production has the potential to provide a more sustainable and efficient alternative to conventional hydrogen production methods. In addition, this work also demonstrates that a computation-driven rational design supplemented by experimental validation is an effective protocol for conducting research on functional self-assembled peptides.

Hydrolase mimic via second coordination sphere engineering in metal-organic frameworks for environmental remediation

Enzymes achieve high catalytic activity with their elaborate arrangements of amino acid residues in confined optimized spaces. Nevertheless, when exposed to complicated environmental implementation scenarios, including high acidity, organic solvent and high ionic strength, enzymes exhibit low operational stability and poor activity. Here, we report a metal-organic frameworks (MOFs)-based artificial enzyme system via second coordination sphere engineering to achieve high hydrolytic activity under mild conditions. Experiments and theoretical calculations reveal that amide cleavage catalyzed by MOFs follows two distinct catalytic mechanisms, Lewis acid- and hydrogen bonding-mediated hydrolytic processes. The hydrogen bond formed in the secondary coordination sphere exhibits 11-fold higher hydrolytic activity than the Lewis acidic zinc ions. The MOFs exhibit satisfactory degradation performance of toxins and high stability under extreme working conditions, including complicated fermentation broth and high ethanol environments, and display broad substrate specificity. These findings hold great promise for designing artificial enzymes for environmental remediation.

Transesterification of RNA model induced by novel dinuclear copper (II) complexes with bis-tridentate imidazole derivatives

Two novel bis-tridentate imidazole derivatives were conveniently synthesized using a 'one-pot' method. Their dinuclear (Cu₂L¹Cl₄, Cu₂L²Cl₄) and mononuclear (CuL¹Cl₂, CuL²Cl₂∙H₂O) copper (II) complexes were synthesized to comparably evaluate their reactivities in the hydrolytic cleavage of 2-hydroxypropyl p-nitrophenyl phosphate (HPNP) as a classic RNA model. Single crystals of Cu₂L¹Cl₄ and Cu₂L²Cl₄ indicate that both of them are centrosymmetric, and each central copper ion is penta-coordinated. Regarding the transesterification of HPNP, both of dinuclear ones exhibited excess one order of magnitude rate enhancement in contrast with auto-hydrolysis reaction. Under comparable conditions, dinuclear complexes displayed no more than twofold increase in activity over their mononuclear analogues, which verifies the lack of binuclear cooperation effect due to long Cu-to-Cu space.

Two-Dimensional Metal-Organic Framework Incorporated Highly Polar PVDF for Dielectric Energy Storage and Mechanical Energy Harvesting

Here, we introduce a 2D metal-organic framework (MOF) into the poly(vinylidene fluoride) (PVDF) matrix, which has been comparatively less explored in this field. Highly 2D Ni-MOF has been synthesized in this regard via hydrothermal route and has been incorporated into PVDF matrix via solvent casting technique with ultralow filler (0.5 wt%) loading. The polar phase percentage of 0.5 wt% Ni-MOF loaded PVDF film (NPVDF) has been found to be increased to ~85% from a value of ~55% for neat PVDF. The ultralow filler loading has inhibited the easy breakdown path along with increased dielectric permittivity and hence has enhanced the energy storage performance. On the other hand, significantly enriched polarity and Young's Modulus has helped in improving its mechanical energy harvesting performance, thereby enhancing the human motion interactive sensing activities. The piezoelectric and piezo-tribo hybrid devices made up of NPVDF film have shown improved output power density of ~3.26 and 31 μW/cm² compared to those of the piezoelectric and piezo-tribo hybrid devices comprising of neat PVDF (output power density ~0.6 and 17 μW/cm², respectively). The developed composite can thus be considered an excellent candidate for multifunctional applications.

Tailored Cross-β Assemblies Establish Peptide "Dominos" Structures for Anchoring Undruggable Pharmacophores

β-sheets have the ability to hierarchically stack into assemblies, and much effort has been spent on designing different peptides to regulate their assembly behaviors. Although the progress is remarkable, it remains challenging to manipulate them in a controllable way for achieving both tailored structures and specific functions. In this study, we obtained bola-like peptides using de novo design and combinatorial chemical screening. By regulating the solvent-accessible surface area of the peptide chain, a series of assemblies with different tilt angles and active sites of the β-sheet were obtained, resembling collapsed dominos. The structure-activity relationship of the optimized peptide NQ40 system was established and its ability to target the PD-L1 was demonstrated. This study successfully established the structure-function relationship of β-sheets assemblies and has positive implications on the rational design of peptide assemblies that possess recognition abilities.

Easy Handling and Cost-Efficient Processing of a Tb3+-MOF: The Emissive Capacity of the Membrane-Immobilized Material, Water Vapour Adsorption and Proton Conductivity

The development of convenient, non-complicated, and cost-efficient processing techniques for packing low-density MOF powders for industry implementation is essential nowadays. To increase MOFs' availability in industrial settings, we propose the synthesis of a novel 3D Tb-MOF (1) and a simple and non-expensive method for its immobilization in the form of pellets and membranes in polymethacrylate (PMMA) and polysulphone (PSF). The photoluminescent properties of the processed materials were investigated. To simulate industrial conditions, stability towards temperature and humidity have been explored in the pelletized material. Water-adsorption studies have been carried out in bulk and processed materials, and because of the considerable capacity to adsorb water, proton-conduction studies have been investigated for 1.

Coordination-Induced Self-Assembly of a Dipeptide into Multifunctional Chiral Nanostructures

Short peptides could be used as chiral motifs to self-assemble into various artificial nanostructures with supramolecular or nanoscale chirality, but their applications still need to be expanded. Here, under the mediation of metal ions, the ferrocene-diphenylalanine (Fc-^LF^LF) peptide can self-assemble into various chiral nanostructures, including right-handed helical microflowers mediated by Cu²⁺, left-handed nanofibers mediated by Ag⁺, and right-handed nanofibers mediated by Zn²⁺ and Cd²⁺. Meanwhile, the gold nanoparticles could be mineralized and deposited on Cu²⁺/Fc-^LF^LF microflowers to form AuNPs@Cu²⁺/Fc-^LF^LF, which showed significantly improved catalytic activity. The Ag⁺ could be further mineralized on the peptide nanofibers to form AgNPs@Fc-^LF^LF, showing an excellent antibacterial effect. Overall, this study provides new insights into the chiral self-assembly of short peptides and demonstrates that the chiral peptide-metal assemblies may have broad prospects in the fields of biocatalysis and antimicrobials.

An artificial self-assembling peptide with carboxylesterase activity and substrate specificity restricted to short-chain acid p-nitrophenyl esters

Natural enzymes possess remarkable catalytic activity and high substrate specificity. Many efforts have been dedicated to construct artificial enzymes with high catalytic activity. However, how to mimic the exquisite substrate specificity of a natural enzyme remains challenging because of the complexity of the enzyme structure. Here, we report artificial carboxylesterases that are specific for short chain fatty acids and were constructed via peptide self-assembly. These artificial systems have esterase-like activity rather than lipase-like activity towards p-nitrophenyl esters. The designer peptides self-assembled into nanofibers with strong β-sheet character. The extending histidine units and the hydrophobic edge of the fibrillar structure collectively form the active center of the artificial esterase. These artificial esterases show substrate specificity for short-chain acids esters. Moreover, 1-isopropoxy-4-nitrobenzene could function as a competitive inhibitor of hydrolysis of p-nitrophenyl acetate for an artificial esterase.