Halogenases in Biocatalysis: Advances in Mechanism Elucidation， Directed Evolution， and Green Manufacturing Synthetic Biology Journal    DOI: 10.12211/2096-8280.2024-091

Fig. 3 Cofactors and catalytic mechanisms of different types of halogenase^[1,4,17-25]

Extracts from the Article

1959年，Shaw和Hager从真菌Caldariomyces fumago中发现了第一个卤化过氧化物酶［28］。随着科学技术的不断进步，科学家们利用基因组测序、蛋白质工程和生物信息学等技术成功地分离并鉴定出一系列具有重要生物学功能的卤化酶，并深入研究了其催化机制和结构特征［1，4，17-25］。由于催化机制不同，卤化酶可以分为三大类，并可根据其催化所需辅因子种类进一步细分。（1）亲电卤化酶（图3a）：催化卤素与底物的亲电结合，包括无辅因子卤素过氧化物酶（Haloperoxidase，HPO）、钒依赖型卤化酶（Vanadium-dependent haloperoxidases，VHPO）、血红素铁依赖型卤化酶（Heme iron-dependent haloperoxidase，HHPO）以及黄素依赖型卤化酶（FDHs）；（2）自由基卤化酶（图3b）：催化卤素对游离或连接特定载体底物的自由基攻击，多为非血红素铁/α-酮戊二酸依赖型卤化酶（Non-Heme iron/α-Ketoglutarate-dependent Halogenases，NHFe/αKGHs），成员包括BesD，WelO5等；（3）亲核卤化酶（图3c）：催化S-腺苷-L-甲硫氨酸（SAM）和卤化物通过双分子亲核取代反应（S_N2）产生5′-氟/氯脱氧腺苷（5′-FDA/5′-ClDA）和L-甲硫氨酸（L-Met），典型代表包括氟酶（Fluorinase，FlA）和氯酶（Chlorinase）。目前，发现及研究最多的卤化酶为亲电卤化酶，其次是自由基卤化酶，而亲核卤化酶仍然是最罕见的。

Other Images/Table from this Article

• Fig. 1  Halogens are the most common and important modification groups in pesticides and pharmaceutical products
• Fig. 2  Examples of halogenated natural products and the role of halogenases in molecular synthesis^[4,12,15-16]
• Fig. 4  Workflow of genome mining for halogenases and their application examples^[34]
• Table 1  Examples of halogenase discovered by genome mining
• Table 2  The uniqueness and superiority of the CLEAN algorithm framework
• Fig. 5  Overview of chloride depletion workflow for revealing cryptic halogenation^[59]
• Fig. 6  The typical structure and catalytic elements of flavin-dependent halogenases
• Fig. 7  The typical structure of single-component flavin-dependent halogenases
• Fig. 8  The proposed catalytic mechanism of PrnA by calculation and simulation^[69]
• Fig. 9  The typical structure of NHFe/αKGHs^[25,70-76]
• Fig. 10  The proposed catalytic mechanism of BesD by calculation and simulation^[80]
• Fig. 11  The action mode and engineering strategies of novel nucleotide halogenase ^[46]
• Fig.12  The structural, function and catalytic mechanism of copper-dependent halogenase ApnU^[81]
• Table 3  Typical engineering cases of natural halogenase in recent years
• Fig. 13  The typical structure SAM-dependent halogenase ^[84-91]The red lines indicate the residues that are crucial for fluorination activity; the yellow lines indicate the residues that can form hydrogen bonds with the modification groups at the C2′ position of adenine
• Fig. 14  Tunnel engineering improves the catalytic performance of Thal halogenase^[96]
• Fig. 15  Directed evolution enhances the fluorination activity of non-heme iron oxidase^[108-109]
• Fig. 16  Biocatalytic synthesis platform of halogenated tryptophan derivatives^[113]
• Tab. 4  Examples of FDHs catalyzing enantioselective reactions^[125-127]
• Tab. 5  Recent cases and key data related to the potential industrial application of halogenases
• Fig. 17  Representative research progress in the field of halogenase research
• Fig. 18  AI/ML drives the intelligent evolution of halogenase^[138-156]