Work

Biochemical and structural insights into pinoresinol hydroxylase from Pseudomonas sp

Year: 2024

Type: article

Abstract: The vanillyl alcohol oxidase/ p -cresol methylhydroxylase (VAO/PCMH) flavoprotein family comprises a broad spectrum of enzymes capable of catalyzing the oxidative bioconversions of various substrates. Among them, pinoresinol hydroxylase (PinH) from the 4-alkylphenol oxidizing subgroup initiates the oxidative degradation of (+)-pinoresinol, a lignan important for both lignin structure and plant defense. In this study, we present a detailed biochemical and structural characterization of PinH from Pseudomonas sp., with focus on its substrate specificity and product formation. PinH was expressed in E. coli and purified as FAD-containing, soluble protein. The flavoenzyme catalyzes the hydroxylation of both (+)-pinoresinol and eugenol. Structural analysis reveals its dimeric form, non-covalent flavin binding, and a large active site. AlphaFold models of the PinH-cytochrome complex demonstrate cytochrome's dual role in electron transfer and modulating PinH's conformation. A distinctive feature of PinH is a large cavity that hosts its multi-ring (+)-pinoresinol substrate. The capability of converting bulky lignans is particularly attractive for biotechnological applications aimed at producing high-value compounds from phenolic precursors. These insights expand our knowledge on the structure and mechanism of the VAO/PCMH flavoenzyme family members. • PinH exhibits several of the mechanistic and structural features typical of the VAO/PCMH flavoenzyme family. • Its characteristic property is a large active-site cavity accommodating multi-ring phenolic compounds. • AlphaFold modeling reveals how its cytochrome partner may induce conformational changes critical for electron transfer. • PinH can be explored for biotechnological applications aimed at the valorization of lignans or lignin-related compounds.

Source: Archives of Biochemistry and Biophysics

DOI: 10.1016/j.abb.2024.110247

Authors: Teresa Benedetta Guerriere, Marco W. Fraaije, Andrea Mattevi

Institutions: University of Pavia, University of Groningen

Language: English

Topic: Biochemical and biochemical processes

Subfield: Biotechnology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $2,940