Biocatalysts immobilization with nanomaterials has promoted the development of biocatalysis significantly and made it an indispensable part of catalysis industries nowadays. Metal–organic frameworks (MOFs), constructed from organic linkers and metal ions or clusters, have raised significant interests for biocatalysts immobilization in recent years. The diversity of building units, molecular‐scale tunability, and modular synthetic routes of MOFs greatly expand its ability as the host to integrate with biocatalysts. In this review, the general synthetic strategies of MOFs with biocatalysts are first summarized. Then, the recent progress of MOFs as a versatile host for a series of biocatalysts, including natural enzymes, nanozymes, and organism‐based biocatalysts, followed by the introduction of MOFs themselves as biocatalysts, is discussed. Furthermore, the stimuli‐responsive properties of MOFs themselves or the additional functionalization of protein, polymer, and peptide within/on MOF that enable the biocatalysts with the controllable and tunable behavior are also summarized, which could unlock new potentials in biocatalysis. Finally, a perspective of the upcoming challenges, potential impacts, and future directions of biocatalytic MOFs is provided.
Advances in artificial/synthetic cells have drawn a new era of nanobiotechnology, which have shown broad prospects in biomedical applications. The rational nanoengineering of synthetic cells that can closely substitute the systematic biological functions of cells is a next grand challenge. Here, a genetically encoded synthetic beta cell, which can sense hyperglycemic conditions to initiate programmed biosynthesis and secretion of insulin is reported. By encapsulating different metal–organic framework‐based artificial organelles with distinctive bifunctionalities, the synthetic cell can undergo programmed, sequential subcellular events, including glucose sensing, initiation of insulin gene transcription and translation, and finally excretion of functional insulin, under hyperglycemic conditions. Glucose uptake assay suggests that the insulin produced by the synthetic cells can successfully promote glucose uptake into mammalian cells. The construction of a higher‐order cell cluster by ligand‐mediated super‐assembly of the synthetic cells is further demonstrated. Such a robust and smart synthetic system that closely mimics the cellular activities of beta cells in response to glucose levels is promising for improving clinical outcomes in diabetes treatment.
Regulating gene expression is an important goal for the development of artificial cells that have the ability to replicate the functions of living cells. Despite that, it remains a critical challenge to the engineering of artificial cells that can self‐regulate genetic expression in response to the “extracellular” environments. Herein, the gene transcription and translation engineered into metal–organic framework (MOF)‐based artificial cells using extracellular pH as a versatile gate to control green fluorescence protein (GFP) expression is reported for the first time. The results show that the artificial cells can metabolize biological molecules through an engineered multistep process of biocatalytic reactions, and importantly, sense acidic pH in the extracellular environment to initiate gene expression, mimicking natural cells. Moreover, co‐culturing with living cells further prove the adaptive cellular responses in the artificial cells when the target proteins can be produced in response to the change in local cell environments. The versatility of the gene expression regulation mechanism and the sensing of external stimuli by artificial cells supports the goal to bring protocells one step closer to native cells and suggests the potential of the artificial systems in biosensing and therapy applications.
Rapeseed (Brassica napus L.) with substantial lipid and oleic acid content is of great interest to rapeseed breeders. Overexpression of Glycine max transcription factors Dof4 and Dof11 increased lipid accumulation in Arabidopsis and microalgae, in addition to modifying the quantity of certain fatty acid components. Here, we report the involvement of GmDof4 and GmDof11 in regulating fatty acid composition in rapeseeds. Overexpression of GmDof4 and GmDof11 in rapeseed increased oleic acid content and reduced linoleic acid and linolenic acid. Both qPCR and the yeast one-hybrid assay indicated that GmDof4 activated the expression of FAB2 by directly binding to the cis-DNA element on its promoters, while GmDof11 directly inhibited the expression of FAD2. Thus, GmDof4 and GmDof11 might modify the oleic acid content in rapeseed by directly regulating the genes that are associated with fatty acid biosynthesis.
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