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Du Y, Lv X, Siebenmorgen T, Popowicz G, Feng C, Ma Y, Wang Y. Enhancing Catalytic Activity of a Baeyer-Villiger monooxygenase from Oceanicola granulosus: Simultaneous Engineering of the Distal Site and Active Site. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2025. [PMID: 40448641 DOI: 10.1021/acs.jafc.5c01791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2025]
Abstract
Enzymatic synthesis of δ-lactones using Baeyer-Villiger monooxygenases (BVMOs) has potential in the fragrance and flavor industries but is constrained by poor activity toward ortho-alkyl-substituted cyclopentanones, key δ-lactone precursors. We determined the crystal structure of a BVMO derived from Oceanicola granulosus (OgBVMO), uncovering a unique loop adjacent to key catalytic residue R335. Site-saturation mutagenesis of loop residues A338 and A339 identified the A339E variant, obtaining a 2.4- to 3-fold increase in catalytic activity toward ortho-alkyl-substituted cyclopentanones (2-methyl-, 2-ethyl-, 2-hexyl-, and 2-heptylcyclopentanone). Further engineering the substrate-binding pocket yielded the Q442N variant, improving activity by 2.7-3.8-fold. Remarkably, the combinatorial mutant A339E/Q442N achieved 3.3-5.2-fold higher activity than the wild-type. Molecular dynamics simulations indicated that these improvements were driven by more favorable nucleophilic attack distances, underscoring the synergistic effects of distal and active-site mutations. These findings offer valuable insights into enhancing the catalytic activity of BVMOs, supporting the green manufacturing of high-value flavor compounds.
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Affiliation(s)
- Yu Du
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
- School of Public Health, Qilu Medical University, Zibo 255300, China
| | - Xiang Lv
- Key Laboratory of Industrial Biotechnology, School of Biotechnology, Jiangnan University, Wuxi 214129, China
| | - Till Siebenmorgen
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Neuherberg 85764, Germany
- TUM School of Natural Sciences, Bavarian NMR Center and Department of Bioscience, Technical University of Munich, Munich 80539, Germany
| | - Grzegorz Popowicz
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Neuherberg 85764, Germany
- TUM School of Natural Sciences, Bavarian NMR Center and Department of Bioscience, Technical University of Munich, Munich 80539, Germany
| | - Chenhao Feng
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yunjian Ma
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yonghua Wang
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
- Guangdong Youmei Institute of Intelligent Bio-Manufacturing Co. Ltd, Foshan 528012, China
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Madubuike H, Ferry N. Characterisation of a Novel Acetyl Xylan Esterase (BaAXE) Screened from the Gut Microbiota of the Common Black Slug ( Arion ater). Molecules 2022; 27:2999. [PMID: 35566348 PMCID: PMC9104356 DOI: 10.3390/molecules27092999] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/29/2022] [Accepted: 05/03/2022] [Indexed: 11/24/2022] Open
Abstract
Acetyl xylan esterases (AXEs) are enzymes capable of hydrolysing the acetyl bonds in acetylated xylan, allowing for enhanced activity of backbone-depolymerizing enzymes. Bioprospecting novel AXE is essential in designing enzyme cocktails with desired characteristics targeting the complete breakdown of lignocellulose. In this article, we report the characterisation of a novel AXE identified as Gene_id_40363 in the metagenomic library analysed from the gut microbiota of the common black slug. The conserved domain description was identified with an NCBI BLASTp search using the translated nucleotide sequence as a query. The activity of the recombinant enzyme was tested on various synthetic substrates and acetylated substrates. The protein sequence matched the conserved domain described as putative hydrolase and aligned closely to an uncharacterized esterase from Buttiauxella agrestis, hence the designation as BaAXE. BaAXE showed low sequence similarity among characterized CE family proteins with an available 3D structure. BaAXE was active on 4-nitrophenyl acetate, reporting a specific activity of 78.12 U/mg and a Km value of 0.43 mM. The enzyme showed optimal activity at 40 °C and pH 8 and showed high thermal stability, retaining over 40% activity after 2 h of incubation from 40 °C to 100 °C. BaAXE hydrolysed acetyl bonds, releasing acetic acid from acetylated xylan and β-D-glucose pentaacetate. BaAXE has great potential for biotechnological applications harnessing its unique characteristics. In addition, this proves the possibility of bioprospecting novel enzymes from understudied environments.
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Affiliation(s)
- Henry Madubuike
- School of Science, Engineering and Environment, University of Salford, Manchester M5 4WT, UK
| | - Natalie Ferry
- School of Science, Engineering and Environment, University of Salford, Manchester M5 4WT, UK
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