Excessive activation of the stimulator of the interferon gene (STING) pathway has been identified as a significant contributor to various autoimmune diseases, such as STINGassociated vasculopathy with infantile-onset (SAVI) and inflammatory bowel disease (IBD). However, discovering effective STING antagonists for treating STING-mediated autoimmune disorders remains challenging. Herein, we identified the natural product anhydrotuberosin (ATS) as a potent STING antagonist by a high-throughput chemical screen and follow-up biological validations. However, the limited supply from natural product isolation impeded the pharmacological evaluations of ATS. Accordingly, we developed a concise and scalable total synthesis of ATS in 6 steps. Enabled by total synthesis, we further extensively investigated ATS’s mode of action and evaluated its therapeutic potential. Remarkably, ATS inhibits STING signaling in PBMCs derived from three SAVI patients. ATS showed decent pharmacokinetic parameters and strongly alleviated tissue inflammation in DSS-induced IBD colitis and Trex1-/- autoimmune animal models with low toxicity. Collectively, this research lays the foundation for developing novel STING antagonists as an effective therapy for autoinflammatory and autoimmune diseases.
Chronic itch is a debilitating symptom profoundly impacting the quality of life in patients with liver diseases like cholestasis. Activation of the human G-protein coupled receptor, MRGPRX4 (hX4), by bile acids (BAs) is implicated in promoting cholestasis itch. However, the detailed underlying mechanisms remain elusive. Here, we identified 3-sulfated BAs that are elevated in cholestatic patients with itch symptoms. We solved the cryo-EM structure of hX4-Gq in a complex with 3-phosphated deoxycholic acid (DCA-3P), a mimic of the endogenous 3-sulfated deoxycholic acid (DCA-3S). This structure revealed an unprecedented ligand-binding pocket in MRGPR family proteins, highlighting the crucial role of the 3-hydroxyl (3-OH) group on BAs in activating hX4. Guided by this structural information, we designed and developed compound 7 (C7), a BA derivative lacking the 3-OH. Notably, C7 effectively alleviates hepatic injury and fibrosis in liver disease models while significantly mitigating the itch side effects.
Fusheng Guo, Fan Xiao, Hao Song, Xiaoyong Li, Yaxin Xiao, Yong Qin,* and Xiaoguang Lei*
ACS central science, 2024. DOI: 10.1021/acscentsci.4c01167
Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogenic bacterium that causes clinical infection and has become one of the most prominent antibiotic-resistant bacteria in the world. There is a pressing need to develop new antibiotics based on novel modes of action to combat increasingly severe MRSA infection. Marinopyrrole A (MA), a natural product extracted from marine Streptomyces in 2008, has a unique bipyrrole chemical skeleton and shows potent antibacterial activity against MRSA. However, its mode of action is still elusive. Herein, we developed an optimized MA derivative, MA-D1, and applied a chemoproteomic approach to reveal that MA-D1 performs its anti-MRSA activity by directly targeting 6-phosphoglucosamine synthetase (GlmS) to cause the breakdown of bacterial cell wall biosynthesis. Computational and experimental studies showed that MA-D1 interacts with the key R381 and E382 residues of GlmS in a novel binding pocket. Furthermore, MA-D1 showed a low resistance frequency for MRSA treatment and was also sensitive against the linezolid-, vancomycin-, or teicoplanin-resistant MRSA strains. MA-D1 also showed in vivo antibiotic efficacy in multiple animal models. This study demonstrates the promising potential of targeting GlmS to develop a new class of antibiotics to control MRSA pathogen infection.
Science, 25 Oct 2024 Vol 386, Issue 6720 DOI: 10.1126/science.adl0799
Tardigrades are captivating organisms known for their resilience in extreme environments, including ultra-high-dose radiation, but the underlying mechanisms of this resilience remain largely unknown. Using genome, transcriptome, and proteome analysis of Hypsibius henanensis sp. nov., we explored the molecular basis contributing to radiotolerance in this organism. A putatively horizontally transferred gene, DOPA dioxygenase 1 (DODA1), responds to radiation and confers radiotolerance by synthesizing betalain —a type of plant pigment with free radical-scavenging properties. A tardigrade-specific radiation-induced disordered protein, TRID1, facilitates DNA damage repair through a mechanism involving phase separation. Two mitochondrial respiratory chain complex assembly proteins, BCS1 and NDUFB8, accumulate to accelerate nicotinamide adenine dinucleotide (NAD+) regeneration for poly (adenosine diphosphate–ribosyl)ation (PARylation) and subsequent poly(adenosine diphosphate–ribose) polymerase 1 (PARP1)–mediated DNA damage repair. These three observations expand our understanding of mechanisms of tardigrade radiotolerance.
Jin Wang, Jianxiong Zhao, Zhenyang Yu, Siyuan Wang, Fusheng Guo, Jun Yang, Lei Gao, Xiaoguang Lei*
Angew. Chem. Int. Ed. 2024, e202414340
The bisbenzylisoquinoline alkaloids (bisBIAs) have attracted tremendous attention from the synthetic community due to their diverse and intriguing biological activities. Herein, we report the convergent and modular chemoenzymatic syntheses of eight bisBIAs bearing various substitutes and linkages in 5-7 steps. The gram-scale synthesis of various well-designed enantiopure benzylisoquinoline monomers was accomplished via an enzymatic stereoselective Pictet–Spengler reaction, followed by regioselective enzymatic methylation or chemical functionalizations in a sequential one-pot process. A modified intermolecular copper-mediated Ullmann coupling enabled the concise and efficient total synthesis of five different linear bisBIAs with either head-to-tail or tail-to-tail linkage. A biomimetic oxidative phenol dimerization selectively formed the sterically hindered, electron-rich diaryl ether bond, and subsequent intramolecular Suzuki–Miyaura domino reaction or Ullmann coupling facilitated the first enantioselective total synthesis of three macrocyclic bisBIAs, including ent-isogranjine, tetrandrine and O-methylrepandine. This study highlights the great potential of chemoenzymatic strategies in the total synthesis of diverse bisBIAs and paves the way to further explore the biological functions of these natural products.
Junping Fan, Han Ke, Jing Lei, Jin Wang, Makoto Tominaga & Xiaoguang Lei.
Nature Communications, 2024, 15, 6689.
Transient Receptor Potential Vanilloid 1 (TRPV1) plays a central role in pain sensation and is thus an attractive pharmacological drug target. SAF312 is a potent, selective, and non-competitive antagonist of TRPV1 and shows promising potential in treating ocular surface pain. However, the precise mechanism by which SAF312 inhibits TRPV1 remains poorly understood. Here, we present the cryo-EM structure of human TRPV1 in complex with SAF312, elucidating the structural foundation of its antagonistic effects on TRPV1. SAF312 binds to the vanilloid binding pocket, preventing conformational changes in S4 and S5 helices, which are essential for channel gating. Unexpectedly, a putative cholesterol was found to contribute to SAF312’s inhibition. Complemented by mutagenesis experiments and molecular dynamics simulations, our research offers substantial mechanistic insights into the regulation of TRPV1 by SAF312, highlighting the interplay between the antagonist and cholesterol in modulating TRPV1 function. This work not only expands our understanding of TRPV1 inhibition by SAF312 but also lays the groundwork for further developments in the design and optimization of TRPV1-related therapies.
The first total synthesis of (+)-epicolidine C has been accomplished via a late-stage HfCl4-mediated epoxide opening from (+)-PF1052. The 6/6/6/5 tetracyclic core of spylidone has also been constructed from (+)-AB4015-B via late-stage iodine(I)- or manganese(III)-mediated oxidative cyclization reactions, whose absolute stereostructure was unambiguously confirmed by X-ray crystallographic analysis.
Lei Gao, Qi Ding, Xiaoguang Lei* Accounts of Chemical Research, doi：10.1021/acs.accounts.4c00315
The Diels–Alder reaction is well known as a concerted [4 + 2] cycloaddition governed by the Woodward–Hoffmann rules. Since Prof. Otto Diels and his student Kurt Alder initially reported the intermolecular [4 + 2] cycloaddition between cyclopentadiene and quinone in 1928, it has been recognized as one of the most powerful chemical transformations to build C–C bonds and construct cyclic structures. This named reaction has been widely used in synthesizing natural products and drug molecules. Driven by the synthetic importance of the Diels–Alder reaction, identifying the enzyme that stereoselectively catalyzes the Diels–Alder reaction has become an intriguing research area in natural product biosynthesis and biocatalysis. With significant progress in sequencing and bioinformatics, dozens of Diels–Alderases have been characterized in microbial natural product biosynthesis. However, few are evolutionally dedicated to catalyzing an intermolecular Diels–Alder reaction with a concerted mechanism.
The nonselective calcium-permeable Transient Receptor Potential Cation Channel Subfamily V Member4 (TRPV4) channel regulates various physiological activities. Dysfunction of TRPV4 is linked to many severe diseases, including edema, pain, gastrointestinal disorders, lung diseases, and inherited neurodegeneration. Emerging TRPV4 antagonists show potential clinical benefits. However, the molecular mechanisms of TRPV4 antagonism remain poorly understood. Here, cryo-electron microscopy (cryo-EM) structures of human TRPV4 are presented in-complex with two potent antagonists, revealing the detailed binding pockets and regulatory mechanisms of TRPV4 gating. Both antagonists bind to the voltage-sensing-like domain (VSLD) and stabilize the channel in closed states. These two antagonists induce TRPV4 to undergo an apparent fourfold to twofold symmetry transition. Moreover, it is demonstrated that one of the antagonists binds to the VSLD extended pocket, which differs from the canonical VSLD pocket. Complemented with functional and molecular dynamics simulation results, this study provides crucial mechanistic insights into TRPV4 regulation by small-molecule antagonists, which may facilitate future drug discovery targeting TRPV4.
Haoran Dong, Nianxin Guo , Dachao Hu, Benke Hong, Daohong Liao, Hong Jie Zhu, Zhang Yuan Yan, Hui Ming Ge & Xiaoguang Lei
Nature Synthesis. Published online: 25 June 2024. doi: 10.1038/s44160-024-00577-7
Alchivemycin A belongs to a unique class of polyketide natural products isolated from plant-derived actinomycete Streptomyces. It shows potent antibacterial activity and anti-tumour activity. However, its inherent structural complexity and high oxidation state, especially the 2H-tetrahydro-4,6-dioxo-1,2-oxazine (TDO) ring system, present synthetic challenges. Here we report the total synthesis of alchivemycin A using a chemoenzymatic approach that combines de novo skeleton construction and late-stage enzymatic oxidation reactions. The convergent synthesis of the highly functionalized unnatural tetramic acid-bearing intermediate is achieved by boron-alkyl Suzuki−Miyaura cross-coupling, macrolactamization and Lacey–Dieckmann condensation reactions. Efficient enzymatic epoxidations using the redox enzymes AvmO3 and AvmO2 allow rapid access to the desired diepoxide product regio- and stereoselectively. Subsequently, a flavin adenine dinucleotide-dependent enzyme AvmO1 variant optimized via rational protein engineering, AvmO1-Y282R, was used to convert the tetramic acid ring into the TDO ring through a Baeyer–Villiger-type transformation, completing the chemoenzymatic synthesis of alchivemycin A. This work paves the way to further explore the biological functions of alchivemycin A and highlights the utility of chemoenzymatic strategies to tackle synthetic challenges in complex molecule synthesis.
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Discovery and Total Synthesis of Anhydrotuberosin as a STING Antagonist for Treating Autoimmune Diseases
Fusheng Guo, Jing Zhang, Yihui Gao, Zhou
Shu, Fei Sun, Jing Ma, Xu Zhou, Wenyang Li, Huawei
Mao*, Xiaoguang Lei*
Angew. Chem. Int. Ed. 2024, e202407641
Excessive activation of the stimulator of the interferon gene (STING) pathway has been identified as a significant contributor to various autoimmune diseases, such as STINGassociated vasculopathy with infantile-onset (SAVI) and inflammatory bowel disease (IBD). However, discovering effective STING antagonists for treating STING-mediated autoimmune disorders remains challenging. Herein, we identified the natural product anhydrotuberosin (ATS) as a potent STING antagonist by a high-throughput chemical screen and follow-up biological validations. However, the limited supply from natural product isolation impeded the pharmacological evaluations of ATS. Accordingly, we developed a concise and scalable total synthesis of ATS in 6 steps. Enabled by total synthesis, we further extensively investigated ATS’s mode of action and evaluated its therapeutic potential. Remarkably, ATS inhibits STING signaling in PBMCs derived from three SAVI patients. ATS showed decent pharmacokinetic parameters and strongly alleviated tissue inflammation in DSS-induced IBD colitis and Trex1-/- autoimmune animal models with low toxicity. Collectively, this research lays the foundation for developing novel STING antagonists as an effective therapy for autoinflammatory and autoimmune diseases.
Structure-guided discovery of bile acid derivatives for treating liver diseases without causing itch
Jun Yang, Tianjun Zhao, Junping Fan, Huaibin Zou, Guangyi Lan, Fusheng Guo, Yaocheng Shi, Han Ke, Huasheng Yu, Zongwei Yue, Xin Wang, Yingjie Bai, Shuai Li, Yingjun Liu, Xiaoming Wang, Yu Chen, Yulong Li, Xiaoguang Lei
Cell, October 29, 2024
Chronic itch is a debilitating symptom profoundly impacting the quality of life in patients with liver diseases like cholestasis. Activation of the human G-protein coupled receptor, MRGPRX4 (hX4), by bile acids (BAs) is implicated in promoting cholestasis itch. However, the detailed underlying mechanisms remain elusive. Here, we identified 3-sulfated BAs that are elevated in cholestatic patients with itch symptoms. We solved the cryo-EM structure of hX4-Gq in a complex with 3-phosphated deoxycholic acid (DCA-3P), a mimic of the endogenous 3-sulfated deoxycholic acid (DCA-3S). This structure revealed an unprecedented ligand-binding pocket in MRGPR family proteins, highlighting the crucial role of the 3-hydroxyl (3-OH) group on BAs in activating hX4. Guided by this structural information, we designed and developed compound 7 (C7), a BA derivative lacking the 3-OH. Notably, C7 effectively alleviates hepatic injury and fibrosis in liver disease models while significantly mitigating the itch side effects.
An Optimized Marinopyrrole A Derivative Targets 6‑Phosphoglucosamine Synthetase to Inhibit Methicillin-Resistant Staphylococcus aureus
Fusheng Guo, Fan Xiao, Hao Song, Xiaoyong Li, Yaxin Xiao, Yong Qin,* and Xiaoguang Lei*
ACS central science, 2024. DOI: 10.1021/acscentsci.4c01167
Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogenic bacterium that causes clinical infection and has become one of the most prominent antibiotic-resistant bacteria in the world. There is a pressing need to develop new antibiotics based on novel modes of action to combat increasingly severe MRSA infection. Marinopyrrole A (MA), a natural product extracted from marine Streptomyces in 2008, has a unique bipyrrole chemical skeleton and shows potent antibacterial activity against MRSA. However, its mode of action is still elusive. Herein, we developed an optimized MA derivative, MA-D1, and applied a chemoproteomic approach to reveal that MA-D1 performs its anti-MRSA activity by directly targeting 6-phosphoglucosamine synthetase (GlmS) to cause the breakdown of bacterial cell wall biosynthesis. Computational and experimental studies showed that MA-D1 interacts with the key R381 and E382 residues of GlmS in a novel binding pocket. Furthermore, MA-D1 showed a low resistance frequency for MRSA treatment and was also sensitive against the linezolid-, vancomycin-, or teicoplanin-resistant MRSA strains. MA-D1 also showed in vivo antibiotic efficacy in multiple animal models. This study demonstrates the promising potential of targeting GlmS to develop a new class of antibiotics to control MRSA pathogen infection.
Multi-omics landscape and molecular basis of radiation tolerance in a tardigrade
Lei Li, Zhengping Ge, Shihao Liu, Kun Zheng, Yaqi Li, Kaiqi Chen, Yesheng Fu, Xiaoguang Lei, Zeling Cui, Yifan Wang, Jin Huang, Yanyan Liu, Mingwang Duan, Zimei Sun, Jun Chen, Liangwei Li, Pan Shen, Guibin Wang, Junmiao Chen, Ruochong Li, Chaoran Li, Zhixiang Yang, Yifan Ning, Arong Luo, Baoyu Chen, Inge Seim, Xin Liu, Fei Wang, Yishan Yao, Fusheng Guo, Maojun Yang, Cui Hua Liu, Guangyi Fan, Lizhi Wang, Dong Yang, Lingqiang Zhang.
Science, 25 Oct 2024
Vol 386, Issue 6720
DOI: 10.1126/science.adl0799
Tardigrades are captivating organisms known for their resilience in extreme environments, including ultra-high-dose radiation, but the underlying mechanisms of this resilience remain largely unknown. Using genome, transcriptome, and proteome analysis of Hypsibius henanensis sp. nov., we explored the molecular basis contributing to radiotolerance in this organism. A putatively horizontally transferred gene, DOPA dioxygenase 1 (DODA1), responds to radiation and confers radiotolerance by synthesizing betalain —a type of plant pigment with free radical-scavenging properties. A tardigrade-specific radiation-induced disordered protein, TRID1, facilitates DNA damage repair through a mechanism involving phase separation. Two mitochondrial respiratory chain complex assembly proteins, BCS1 and NDUFB8, accumulate to accelerate nicotinamide adenine dinucleotide (NAD+) regeneration for poly (adenosine diphosphate–ribosyl)ation (PARylation) and subsequent poly(adenosine diphosphate–ribose) polymerase 1 (PARP1)–mediated DNA damage repair. These three observations expand our understanding of mechanisms of tardigrade radiotolerance.
Concise and Modular Chemoenzymatic Total Synthesis of Bisbenzylisoquinoline Alkaloids
Jin Wang, Jianxiong Zhao, Zhenyang Yu,
Siyuan Wang, Fusheng Guo, Jun Yang, Lei Gao, Xiaoguang Lei*
Angew. Chem. Int. Ed. 2024, e202414340
The bisbenzylisoquinoline alkaloids (bisBIAs) have attracted tremendous attention from the synthetic community due to their diverse and intriguing biological activities. Herein, we report the convergent and modular chemoenzymatic syntheses of eight bisBIAs bearing various substitutes and linkages in 5-7 steps. The gram-scale synthesis of various well-designed enantiopure benzylisoquinoline monomers was accomplished via an enzymatic stereoselective Pictet–Spengler reaction, followed by regioselective enzymatic methylation or chemical functionalizations in a sequential one-pot process. A modified intermolecular copper-mediated Ullmann coupling enabled the concise and efficient total synthesis of five different linear bisBIAs with either head-to-tail or tail-to-tail linkage. A biomimetic oxidative phenol dimerization selectively formed the sterically hindered, electron-rich diaryl ether bond, and subsequent intramolecular Suzuki–Miyaura domino reaction or Ullmann coupling facilitated the first enantioselective total synthesis of three macrocyclic bisBIAs, including ent-isogranjine, tetrandrine and O-methylrepandine. This study highlights the great potential of chemoenzymatic strategies in the total synthesis of diverse bisBIAs and paves the way to further explore the biological functions of these natural products.
Structural basis of TRPV1 inhibition by SAF312 and cholesterol
Junping Fan, Han Ke, Jing Lei, Jin Wang, Makoto Tominaga & Xiaoguang Lei.
Nature Communications, 2024, 15, 6689.
Transient Receptor Potential Vanilloid 1 (TRPV1) plays a central role in pain sensation and is thus an attractive pharmacological drug target. SAF312 is a potent, selective, and non-competitive antagonist of TRPV1 and shows promising potential in treating ocular surface pain. However, the precise mechanism by which SAF312 inhibits TRPV1 remains poorly understood. Here, we present the cryo-EM structure of human TRPV1 in complex with SAF312, elucidating the structural foundation of its antagonistic effects on TRPV1. SAF312 binds to the vanilloid binding pocket, preventing conformational changes in S4 and S5 helices, which are essential for channel gating. Unexpectedly, a putative cholesterol was found to contribute to SAF312’s inhibition. Complemented by mutagenesis experiments and molecular dynamics simulations, our research offers substantial mechanistic insights into the regulation of TRPV1 by SAF312, highlighting the interplay between the antagonist and cholesterol in modulating TRPV1 function. This work not only expands our understanding of TRPV1 inhibition by SAF312 but also lays the groundwork for further developments in the design and optimization of TRPV1-related therapies.
Synthesis of (+)-epicolidine C and the 6/6/6/5 tetracyclic core of spylidone
Haoran Dong, Xiaoguang Lei
Tetrahedron Letters, 2024, 146, 155181.
The first total synthesis of (+)-epicolidine C has been accomplished via a late-stage HfCl4-mediated epoxide opening from (+)-PF1052. The 6/6/6/5 tetracyclic core of spylidone has also been constructed from (+)-AB4015-B via late-stage iodine(I)- or manganese(III)-mediated oxidative cyclization reactions, whose absolute stereostructure was unambiguously confirmed by X-ray crystallographic analysis.
Hunting for the Intermolecular Diels−Alderase
Lei Gao, Qi Ding, Xiaoguang Lei*
Accounts of Chemical Research, doi：10.1021/acs.accounts.4c00315
The Diels–Alder reaction is well known as a concerted [4 + 2] cycloaddition governed by the Woodward–Hoffmann rules. Since Prof. Otto Diels and his student Kurt Alder initially reported the intermolecular [4 + 2] cycloaddition between cyclopentadiene and quinone in 1928, it has been recognized as one of the most powerful chemical transformations to build C–C bonds and construct cyclic structures. This named reaction has been widely used in synthesizing natural products and drug molecules. Driven by the synthetic importance of the Diels–Alder reaction, identifying the enzyme that stereoselectively catalyzes the Diels–Alder reaction has become an intriguing research area in natural product biosynthesis and biocatalysis. With significant progress in sequencing and bioinformatics, dozens of Diels–Alderases have been characterized in microbial natural product biosynthesis. However, few are evolutionally dedicated to catalyzing an intermolecular Diels–Alder reaction with a concerted mechanism.
Structural Pharmacology of TRPV4 Antagonists
Junping Fan, Chang Guo, Daohong Liao, Han Ke, Jing Lei, Wenjun Xie, Yuliang Tang, Makoto Tominaga, Zhuo Huang, Xiaoguang Lei
Advanced Science 2024, e2401583. doi: 10.1002/advs.202401583
The nonselective calcium-permeable Transient Receptor Potential Cation Channel Subfamily V Member4 (TRPV4) channel regulates various physiological activities. Dysfunction of TRPV4 is linked to many severe diseases, including edema, pain, gastrointestinal disorders, lung diseases, and inherited neurodegeneration. Emerging TRPV4 antagonists show potential clinical benefits. However, the molecular mechanisms of TRPV4 antagonism remain poorly understood. Here, cryo-electron microscopy (cryo-EM) structures of human TRPV4 are presented in-complex with two potent antagonists, revealing the detailed binding pockets and regulatory mechanisms of TRPV4 gating. Both antagonists bind to the voltage-sensing-like domain (VSLD) and stabilize the channel in closed states. These two antagonists induce TRPV4 to undergo an apparent fourfold to twofold symmetry transition. Moreover, it is demonstrated that one of the antagonists binds to the VSLD extended pocket, which differs from the canonical VSLD pocket. Complemented with functional and molecular dynamics simulation results, this study provides crucial mechanistic insights into TRPV4 regulation by small-molecule antagonists, which may facilitate future drug discovery targeting TRPV4.
Chemoenzymatic total synthesis of alchivemycin A
Haoran Dong, Nianxin Guo , Dachao Hu, Benke Hong, Daohong Liao, Hong Jie Zhu, Zhang Yuan Yan, Hui Ming Ge & Xiaoguang Lei
Nature Synthesis. Published online: 25 June 2024.
doi: 10.1038/s44160-024-00577-7
Alchivemycin A belongs to a unique class of polyketide natural products isolated from plant-derived actinomycete Streptomyces. It shows potent antibacterial activity and anti-tumour activity. However, its inherent structural complexity and high oxidation state, especially the 2H-tetrahydro-4,6-dioxo-1,2-oxazine (TDO) ring system, present synthetic challenges. Here we report the total synthesis of alchivemycin A using a chemoenzymatic approach that combines de novo skeleton construction and late-stage enzymatic oxidation reactions. The convergent synthesis of the highly functionalized unnatural tetramic acid-bearing intermediate is achieved by boron-alkyl Suzuki−Miyaura cross-coupling, macrolactamization and Lacey–Dieckmann condensation reactions. Efficient enzymatic epoxidations using the redox enzymes AvmO3 and AvmO2 allow rapid access to the desired diepoxide product regio- and stereoselectively. Subsequently, a flavin adenine dinucleotide-dependent enzyme AvmO1 variant optimized via rational protein engineering, AvmO1-Y282R, was used to convert the tetramic acid ring into the TDO ring through a Baeyer–Villiger-type transformation, completing the chemoenzymatic synthesis of alchivemycin A. This work paves the way to further explore the biological functions of alchivemycin A and highlights the utility of chemoenzymatic strategies to tackle synthetic challenges in complex molecule synthesis.