Two different aspects of natural multi-modular diversity within a xylan utilization locus to investigate catalytic synergism - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement
Conference Papers Year : 2022

Two different aspects of natural multi-modular diversity within a xylan utilization locus to investigate catalytic synergism

Abstract

Plant biomass acting enzymes (CAZYmes) are central components of biorefinery processes that aim to convert lignocelluloses into molecules of interest. Therefore, efforts to discover, characterize or design novel Cazymes are particularly relevant to valorize lignocellulosic biomass for industrial purposes. In Nature, microorganisms deploy different strategies to degrade plant cell wall including secretion of multi-modular enzymes, cellulosomes anchored at the surface of microbes or genetic organizations (polysaccharide utilization loci PUL) aiming to orchestrate the breakdown of a specific glycan. Thanks to functional metagenomics we discovered new enzymes from the gut microbiome of the termite Pseudacanthotermes militaris (1). This study highlighted an interesting hypothetical xylan PUL, encoding five glycoside hydrolases ( GH) and one carbohydrate esterase (CE) annotated from Bacteroidales. Among the GHs, a novel GH10 encoding sequence Pm25, showed details of an unusual domain organization. It consists of one catalytic domain, which is intercalated by two Carbohydrate Binding Modules (CBMs). This multi-modular organization was shown to be vastly distributed in different xylan PUL found in Bacteroidetes, demonstrating its importance in the glycan foraging for the gut microbiota (2). Therefore,36 the xylan PUL can serve as a model not only to explore the role of enzyme multimodularity but also as a basis to develop synergy between enzymes. In this work, we will present the detailed biochemical and structural characterization of Pm25 with or without its CBMs. The role of the CBMs was also investigated and quantification of their interactions towards carbohydrate led to better understand the specific role of these modules (3). Moreover, in order to explore the molecular basis of the enzymatic synergy, a crucial parameter for the valorization of lignocellulosic biomass, we have recently developed a coevolution strategy using a xylanase and a xylosidase from the PUL. We will present the development of the screening and preliminary biochemical characterization of the best arabinoxylan-active mutants. All these results contribute to a better understanding of the molecular determinants to design novel biotechnological tools for plant biomass valorization.
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Dates and versions

hal-04747254 , version 1 (21-10-2024)

Identifiers

  • HAL Id : hal-04747254 , version 1

Cite

Haiyang Wu, Ahmed Khamassi, Eleni Ioannou, Thomas Enjalbert, Sophie Bozonnet, et al.. Two different aspects of natural multi-modular diversity within a xylan utilization locus to investigate catalytic synergism. LignoBiotech, Aug 2022, Vancouver (BC), Canada. ⟨hal-04747254⟩
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