The aim of this work was to develop a comprehensive workflow to elucidate molecular features of artichoke pectic oligosaccharides (POS) contributing to high potential prebiotic activity. First, obtainment of artichoke POS by Pectinex® Ultra-Olio was optimised using an artificial neural network. Under optimal conditions (pH 6.86; 1.5 h; enzyme dose 520.5 U/g pectin) POS yield was 624 mg/g pectin. Oligosaccharide structures (Mw < 1.3 kDa) were characterised by MALDI-TOF-MS. Then, conformational analysis of glycosidic bonds was performed by replica exchange molecular dynamics simulations and interaction mechanisms between POS and several microbial glycosidases were proposed by molecular modelling. Chemical information was integrated in virtual simulations of colonic fermentation. Highest hydrolysis rate was obtained for GalA-Rha-GalA trisaccharide, while the presence of partial negative charges and high radius of gyration enhance short chain fatty acid formation in distal colon. Established structure-activity relationships could help the rational design of prebiotics and clinical trials.
Keywords: Artificial neural network; Butyrate (PubChem CID: 104775); Conformational analysis; Digalacturonic acid (PubChem CID: 439694); Endo-polygalacturonase (EC: 3.2.1.15); Galacturonic acid (PubChem CID: 439215); Molecular descriptors; Molecular docking; Molecular dynamics; POS; Pectin (PubChem CID: 441476); Rhamnogalacturonyl hydrolase (EC: 3.2.1.172); Tetragalacturonic acid (PubChem CID: 5459352); Trigalacturonic acid (PubChem CID: 4472903); α-l-arabinofuranosidase (EC: 3.2.1.55); β-Galactosidase (EC: 3.2.1.23).
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