Unique properties of a Dictyostelium discoideum carbohydrate-binding module expand our understanding of CBM-ligand interactions.

Autor:	Liberato MV; Programa de Processos Tecnológicos e Ambientais, Universidade de Sorocaba (UNISO), Sorocaba, SP, Brazil., Campos BM; Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brazil., Tomazetto G; Department of Biological and Chemical Engineering (BCE), Aarhus University, Aarhus, Denmark., Crouch LI; Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom., Garcia W; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC (UFABC), Santo André, São Paulo, Brazil., Zeri ACM; Laboratório Nacional de Luz Sincrotron (LNLS), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brazil., Bolam DN; Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle, United Kingdom., Squina FM; Programa de Processos Tecnológicos e Ambientais, Universidade de Sorocaba (UNISO), Sorocaba, SP, Brazil. Electronic address: fabio.squina@gmail.com.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2022 May; Vol. 298 (5), pp. 101891. Date of Electronic Publication: 2022 Apr 01.
DOI:	10.1016/j.jbc.2022.101891
Abstrakt:	Deciphering how enzymes interact, modify, and recognize carbohydrates has long been a topic of interest in academic, pharmaceutical, and industrial research. Carbohydrate-binding modules (CBMs) are noncatalytic globular protein domains attached to carbohydrate-active enzymes that strengthen enzyme affinity to substrates and increase enzymatic efficiency via targeting and proximity effects. CBMs are considered auspicious for various biotechnological purposes in textile, food, and feed industries, representing valuable tools in basic science research and biomedicine. Here, we present the first crystallographic structure of a CBM8 family member (CBM8), DdCBM8, from the slime mold Dictyostelium discoideum, which was identified attached to an endo-β-1,4-glucanase (glycoside hydrolase family 9). We show that the planar carbohydrate-binding site of DdCBM8, composed of aromatic residues, is similar to type A CBMs that are specific for crystalline (multichain) polysaccharides. Accordingly, pull-down assays indicated that DdCBM8 was able to bind insoluble forms of cellulose. However, affinity gel electrophoresis demonstrated that DdCBM8 also bound to soluble (single chain) polysaccharides, especially glucomannan, similar to type B CBMs, although it had no apparent affinity for oligosaccharides. Therefore, the structural characteristics and broad specificity of DdCBM8 represent exceptions to the canonical CBM classification. In addition, mutational analysis identified specific amino acid residues involved in ligand recognition, which are conserved throughout the CBM8 family. This advancement in the structural and functional characterization of CBMs contributes to our understanding of carbohydrate-active enzymes and protein-carbohydrate interactions, pushing forward protein engineering strategies and enhancing the potential biotechnological applications of glycoside hydrolase accessory modules. Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article. (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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