<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Trovão, Filipa</style></author><author><style face="normal" font="default" size="100%">Correia, Viviana G.</style></author><author><style face="normal" font="default" size="100%">Lourenço, Frederico M.</style></author><author><style face="normal" font="default" size="100%">Ribeiro, Diana O.</style></author><author><style face="normal" font="default" size="100%">Carvalho, Ana Luísa</style></author><author><style face="normal" font="default" size="100%">Palma, Angelina S.</style></author><author><style face="normal" font="default" size="100%">Pinheiro, Benedita A.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The structure of a Bacteroides thetaiotaomicron carbohydrate-binding module provides new insight into the recognition of complex pectic polysaccharides by the human microbiome</style></title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Carbohydrate Binding Module</style></keyword><keyword><style  face="normal" font="default" size="100%">Carbohydrates</style></keyword><keyword><style  face="normal" font="default" size="100%">Human Gut Microbiota</style></keyword><keyword><style  face="normal" font="default" size="100%">Rhamnogalacturonan II</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2023</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2023</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.sciencedirect.com/science/article/pii/S2590152422000253</style></url></web-urls></urls><pages><style face="normal" font="default" size="100%">100084</style></pages><isbn><style face="normal" font="default" size="100%">2590-1524</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;TheBacteroides thetaiotaomicronhas developed a consortium of enzymes capable of overcoming steric constraints and degrading, in a sequential manner, the complex rhamnogalacturonan II (RG-II) polysaccharide. BT0996 protein acts in the initial stages of the RGII depolymerisation, where its two catalytic modules remove the terminal monosaccharides from RG-II side chains A and B. BT0996 is modular and has three putative carbohydrate-binding modules (CBMs) for which the roles in the RG-II degradation are unknown. Here, we present the characterisation of themoduleat the C-terminal domain, which we designated BT0996C. The high-resolution structure obtained by X-ray crystallography reveals that the protein displays a typical β-sandwich fold with structural similarity to CBMs assigned to families 6 and 35. The distinctive features are: 1) the presence of several charged residues at the BT0996-C surface creating a large, broad positive lysine-rich patch that encompasses the putative binding site; and 2) the absence of the highly conserved binding-site signatures observed in CBMs from families 6 and 35, such as region A tryptophan and region C asparagine. These findings hint at a binding mode of BT0996-C not yet observed in its homologues. In line with this, carbohydrate microarrays and microscale thermophoresis show the ability of BT0996-C to bind α1-4-linked polygalacturonic acid, and that electrostatic interactions are essential for the recognition of the anionic polysaccharide. The results support the hypothesis that BT0996-C may have evolved to potentiate the action of BT0996 catalytic modules on the complex structure of RG-II by binding to the polygalacturonic acid backbone sequence.&lt;/p&gt;
</style></abstract><notes><style face="normal" font="default" size="100%">&lt;p&gt;n/a&lt;/p&gt;
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