Lijun Yang,Yi Tian,Yutong Wang,Wei Qi,Mengfan Wang
Recently, peptide-based artificial enzymes have attracted growing interest due to the similar composition of peptide assemblies to natural enzymes. However, low catalytic activity and stability are still the main challenges for these enzyme-like catalysts. In this study, a tyrosine strategy was developed to construct a peptide-based artificial glycosidase through engaging the Tyr residue into the peptide sequence. We found that the appropriate substitution of Tyr produced an enhanced catalytic ability, because the proximal Tyr residue around catalytic sites acts as a nucleophile, playing an important role in the substrate orientation and proton transfer. Moreover, inspired by the biological function of dityrosine bonds in structural proteins, a photo-crosslinking reaction between the phenolic side chains of Tyr was also employed to form intermolecular covalent bonds in peptide assemblies, which further improved the activity and stability of the artificial glycosidase. This work provides a simple avenue for the designing and construction of efficient glycosidase-like catalysts based on a peptide-based material platform.
Mingjie Zhu,Mengfan Wang,Wei Qi,Rongxin Su,Zhimin He
Peptide-based materials are promising building blocks for the fabrication of artificial enzymes due to their proteic nature and tailorable structure. However, it is still a big challenge to create artificial enzymes with designable selectivity. In this study, the molecular imprinting strategy was combined with the self-assembly of Fmoc-FFH to create an artificial hydrolase with specific selectivity. By using p-NPA as the imprinting template, we found that the imprinted polymer that was coated on the surface of the catalytic peptide nanofibers provided a specific binding site to p-NPA, hence enhancing the catalytic efficiency of the artificial hydrolase. Furthermore, we confirmed that the substrate selectivity of this artificial enzyme can be customized by changing the imprinting template. The obtained catalyst is recyclable and exhibits a higher catalytic activity at a wider reaction temperature and pH due to the introduction of the polymer. This study provides a new approach to constructing enzyme mimics with customized substrate selectivity based on the peptide-based material platform.
This study presents the development of three new chiral stationary phases. They are based on silica modified with peptides containing phenylalanine and proline. Successful analyses and characterizations were conducted using Fourier transform infrared spectra, elemental analysis, and thermogravimetric analysis. After this, the enantioselective performance of the three chiral peptide-based columns was evaluated. The evaluation used 11 racemic compounds under normal-phase high performance liquid chromatography mode. Optimized enantiomeric separation conditions were established. Under these conditions, the enantiomers of flurbiprofen and naproxen were successfully separated on CSP-1 column: the separation factor of these was 1.27 and 1.21, respectively. In addition, the reproducibility of the CSP-1 column was also investigated. The results of the investigation illustrated that the stationary phases have good reproducibility (RSD = 0.73%, n = 5).
Yao Wang,Ziqi Wang,Lujuan Yang,Ziyang Liu,Chunfang Zhang,Yanli Shang,Gang Ma
Understanding the nucleation mechanism of peptide self-assembly is fundamental for the design and application of peptide-based materials. To this end, we herein explored the self-assembly processes of three diphenylalanine (FF) derivatives, Boc-XF, Boc-FX, and Boc-FF, where X is p -cyanophenylalanine with the cyano group being an infrared (IR) probe. Using IR probe technique and scanning electron microscopy (SEM), we revealed that the self-assembly of Boc-XF followed a three-step non-classical nucleation mechanism. Such a complex mechanism involved the presence of metastable spherical and fibrillar intermediates towards the final mature fibril phase. We further compared the self-assembly mechanism of Boc-XF with that of Boc-FF and Boc-FX and explored the potential impact of side-chain mutation on the peptide self-assembly mechanism. Our research provided a nice example of how to use a combined approach of IR probe technique and SEM to reveal the complex nucleation mechanism of peptide self-assembly.
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