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Phienluphon A, Kondo K, Mikami B, Nagata T, Katahira M. Structural insights into the molecular mechanisms of substrate recognition and hydrolysis by feruloyl esterase from Aspergillus sydowii. Int J Biol Macromol 2023; 253:127188. [PMID: 37783244 DOI: 10.1016/j.ijbiomac.2023.127188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 09/06/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
The depolymerization of lignocellulosic biomass is facilitated by feruloyl esterases (FAEs), which hydrolyze ester bonds between lignin and polysaccharides. Fungal FAEs belonging to subfamily (SF) 6 release precursors such as ferulic acid derivatives, attractive for biochemical production. Among these, Aspergillus sydowii FAE (AsFaeE), an SF6 FAE, exhibits remarkable activity across various substrates. In this study, we conducted X-ray crystallography and kinetic analysis to unravel the molecular mechanisms governing substrate recognition and catalysis by AsFaeE. AsFaeE exhibits a typical α/β-hydrolase fold, characterized by a catalytic triad of serine, aspartate, and histidine. Comparative analysis of substrate-free, ferulic acid-bound, and sinapic acid-bound forms of AsFaeE suggests a conformational change in the loop covering the substrate-binding pocket upon binding. Notably, Pro158 and Phe159 within this loop cover the phenolic part of the substrate, forming three layers of planar rings. Our structure-based functional mutagenesis clarifies the roles of the residues involved in substrate binding and catalytic activity. Furthermore, distinct substrate-binding mechanisms between AsFaeE and other studied FAEs are identified. This investigation offers the initial structural insights into substrate recognition by SF6 FAEs, equipping us with structural knowledge that might facilitate the design of FAE variants capable of efficiently processing a wider range of substrate sizes.
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Affiliation(s)
- Apisan Phienluphon
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Keiko Kondo
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Integrated Research Center for Carbon Negative Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Biomass Product Tree Industry-Academia Collaborative Research Laboratory, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Bunzo Mikami
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takashi Nagata
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Integrated Research Center for Carbon Negative Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Biomass Product Tree Industry-Academia Collaborative Research Laboratory, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
| | - Masato Katahira
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Integrated Research Center for Carbon Negative Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; Biomass Product Tree Industry-Academia Collaborative Research Laboratory, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
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