title: Neutral sugar side chains of pectins limit interactions with procyanidins.
abstract: Interactions between seven hairy regions of pectins, rhamnogalacturonans II and arabinogalactan-proteins and procyanidins with different average degrees of polymerization, low (DP9) and high (DP30), were investigated by isothermal titration calorimetry and absorption analysis to study the impact of neutral sugar side chains of pectins on these associations. Associations between pectic fractions and procyanidins involved hydrophobic interactions and hydrogen bonds. No difference in association constants between various hairy regions and procyanidins DP9 was found. Nevertheless, arabinan chains showed lower association constants, and hairy regions of pectins with only monomeric side chains showed higher association with procyanidin DP30. Only very low affinities were obtained with rhamnogalacturonans II and arabinogalactan-proteins. Aggregation could be observed only with the procyanidins of DP30 and the protein-rich arabinogalactan-protein. Associations were obtained at both degrees of polymerization of the procyanidins, but differed depending on neutral sugar composition and the structure of pectic fractions.
authors.affiliation: INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, F-84000 Avignon, France; Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, F-84000 Avignon, France. Electronic address: watrelotaude@yahoo.fr.
authors.forename: Aude A
authors.initials: AA
authors.lastname: Watrelot
authors.forename: Carine
authors.initials: C
authors.lastname: Le Bourvellec
authors.forename: Anne
authors.initials: A
authors.lastname: Imberty
authors.forename: Catherine M G C
authors.initials: CM
authors.lastname: Renard
mesh_terms: D002151:Calorimetry; D005638:Fruit / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D027845:Malus / Q000737:chemistry*; D009088:Mucoproteins / Q000737:chemistry*; D010368:Pectins / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry; D058105:Polymerization; D044945:Proanthocyanidins / Q000737:chemistry*; D011485:Protein Binding; D013053:Spectrophotometry; D013816:Thermodynamics
chemical_list: D009088:Mucoproteins; D010940:Plant Proteins; D044945:Proanthocyanidins; C006619:arabinogalactan proteins; C042492:rhamnogalacturonan II; D010368:Pectins
keywords: Association; Condensed tannins; ITC; Polyphenol; Polysaccharide; Rhamnogalacturonan