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Ability of a salivary intrinsically unstructured protein to bind different tannin targets revealed by mass spectrometry
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Edité par CCSD ; Springer Verlag -
Anal. Bioanal. Chem. ISI Document Delivery No.: 650IL Times Cited: 10 Cited Reference Count: 58 Canon, Francis Giuliani, Alexandre Pate, Franck Sarni-Manchado, Pascale French Ministry of Research; French Agence Nationale de la Recherche (A.N.R.) [07-BLAN-0279] The authors thank Dr. Veronique Cheynier for helpful scientific discussions, Therese Marlin for protein purification, Jean-Paul Mazauric for tannin purification and Emmanuelle Meudec for mass spectrometry assistance. Francis Canon was supported by a grant of French Ministry of Research. This work is supported by grant 07-BLAN-0279 from the French Agence Nationale de la Recherche (A.N.R.). We acknowledge synchrotron SOLEIL and thank all staff for assistance in using beamline DISCO. AG thanks ABSciex (Les Ullis, France) for the loan of the IonCooler Guide. Springer heidelberg Heidelberg. International audience. Astringency is thought to result from the interaction between salivary proline-rich proteins (PRP) that belong to the intrinsically unstructured protein group (IUP), and tannins, which are phenolic compounds. IUPs have the ability to bind several and/or different targets. At the same time, tannins have different chemical features reported to contribute to the sensation of astringency. The ability of both electrospray ionization mass spectrometry and tandem mass spectrometry to investigate the noncovalent interaction occurring between a human salivary PRP, IB5, and a model tannin, epigallocatechin 3-O-gallate (EgCG), has been reported. Herein, we extend this method to study the effect of tannin chemical features on their interaction with IB5. We used five model tannins, epigallocatechin (EgC), epicatechin 3-O-gallate (ECG), epigallocatechin 3-O-gallate (EgCG), procyanidin dimer B2 and B2 3'-O-gallate, which cover the main tannin chemical features: presence of a gallate moiety (galloylation), the degree of polymerization, and the degree of B ring hydroxylation. We show the ability of IB5 to bind these tannins. We report differences in stoichiometries and in stability of the IB5aEuro cent 1 tannin complexes. These results demonstrate the main role of hydroxyl groups in these interactions and show the involvement of hydrogen bonds. Finally, these results are in line with sensory analysis, by Vidal et al. (J Sci Food Agric 83:564-573, 2003) pointing out that the chain length and the level of galloylation are the main factors affecting astringency perception.
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