Mao Xuanxiang, Qiu Dehui, Wei Shijiong, Zhang Xiaobo, Lei Jianping, Mergny Jean-Louis, Ju Huangxian, Zhou Jun
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P.R. China.
Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France.
ACS Appl Mater Interfaces. 2022 Dec 14;14(49):54598-54606. doi: 10.1021/acsami.2c18473. Epub 2022 Dec 2.
Biocatalytic transformations in living cells, such as enzymatic cascades, function effectively in spatially confined microenvironments. However, mimicking enzyme catalytic cascade processes is challenging. Herein, we report a new dual-Hemin-G-quadruplex (dHemin-G4) DNAzyme with high catalytic activity over noncovalent G4/Hemin and monocovalent counterparts (G4-Hemin and Hemin-G4) by covalently linking hemin to both ends of an intramolecular G4. We use MAF-7, a hydrophilic metal-organic framework (MOF), as the protecting scaffold to integrate a biocatalytic cascade consisting of dHemin-G4 DNAzyme and glucose oxidase (GOx), by a simple and mild method with a single-step encapsulation of both enzymes. Such a MAF-7-confined cascade system shows superior activity over not only traditional G4/Hemin but also other MOFs (ZIF-8 and ZIF-90), which was mainly attributed to high-payload enzyme packaging. Notably, the introduction of hydrophilic G4 allows to avoid the accumulation of hydrophobic hemin on the surface of MAF-7, which decreases cascade biocatalytic activity. Furthermore, MAF-7 as protective coatings endowed the enzyme with excellent recyclability and good operational stability in harsh environments, including elevated temperature, urea, protease, and organic solvents, extending its practical application in biocatalysis. In addition, the incorporated enzymes can be replaced on demand to broaden the scope of catalytic substrates. Taking advantages of these features, the feasibility of dHemin-G4/GOx@MAF-7 systems for biosensing was demonstrated. This study is conducive to devise efficient and stable enzyme catalytic cascades to facilitate applications in biosensing and industrial processes.
活细胞中的生物催化转化，如酶级联反应，在空间受限的微环境中能有效发挥作用。然而，模拟酶催化级联反应过程具有挑战性。在此，我们报道了一种新型双血红素 - G - 四链体（dHemin - G4）脱氧核酶，通过将血红素共价连接到分子内G4的两端，其催化活性高于非共价G4/血红素和单共价对应物（G4 - 血红素和血红素 - G4）。我们使用亲水性金属有机框架（MOF）MAF - 7作为保护支架，通过一种简单温和的方法，一步封装两种酶，整合了由dHemin - G4脱氧核酶和葡萄糖氧化酶（GOx）组成的生物催化级联反应。这种MAF - 7限制的级联系统不仅比传统的G4/血红素表现出更高的活性，而且优于其他MOF（ZIF - 8和ZIF - 90），这主要归因于高负载量的酶封装。值得注意的是，亲水性G4的引入避免了疏水性血红素在MAF - 7表面的积累，这会降低级联生物催化活性。此外，MAF - 7作为保护涂层赋予了酶在包括高温、尿素、蛋白酶和有机溶剂等恶劣环境下优异的可回收性和良好的操作稳定性，扩展了其在生物催化中的实际应用。此外，可以根据需要替换掺入的酶，以扩大催化底物的范围。利用这些特性，证明了dHemin - G4/GOx@MAF - 7系统用于生物传感的可行性。这项研究有助于设计高效稳定的酶催化级联反应，以促进在生物传感和工业过程中的应用。
