@article{Hendrickx2020,

title = {Numerous severely twisted N-acetylglucosamine conformations found in the protein databank},

author = {Johann Hendrickx and Vinh Tran and Yves-Henri Sanejouand},

doi = {10.1002/prot.25957},

issn = {10970134},

year  = {2020},

date = {2020-01-01},

journal = {Proteins: Structure, Function and Bioinformatics},

volume = {88},

number = {10},

pages = {1376--1383},

abstract = {Taking advantage of the known planarity of the N-acetyl group of N-acetylglucosamine, an analysis of the quality of carbohydrate structures found in the protein databank was performed. Few obvious defects of the local geometry of the carbonyl group were observed. However, the N-acetyl group was often found in the less favorable cis conformation (12% of the cases). It was also found severely twisted in numerous instances, especially in structures with a resolution poorer than 1.9 Å determined between 2000 and 2015. Though the automated PDB-REDO procedure has proved able to improve nearly 85% of the structural models deposited to the PDB, and does prove able to cure most severely twisted conformations of the N-acetyl group, it fails to correct its high rate of cis conformations. More generally, for structures with a resolution poorer than 1.6 Å, it produces N-acetylglucosamine models in slightly poorer agreement with experimental data, as measured using real-space correlation coefficients. Significant improvements are thus still needed, at least as far as this carbohydrate structure is concerned.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Le-Bail2015,

title = {Trapping by amylose of the aliphatic chain grafted onto chlorogenic acid: Importance of the graft position},

author = {Patricia Le-Bail and C Lorentz and G Pencreac'h and S Soultani-Vigneron and B Pontoire and J.López L Giraldo and P Villeneuve and Johann Hendrickx and Vinh Tran},

url = {http://dx.doi.org/10.1016/j.carbpol.2014.10.029},

doi = {10.1016/j.carbpol.2014.10.029},

issn = {01448617},

year  = {2015},

date = {2015-01-01},

journal = {Carbohydrate Polymers},

volume = {117},

pages = {910--916},

publisher = {Elsevier Ltd.},

abstract = {5-Caffeoylquinic acid (chlorogenic acid), is classified in acid-phenols family and as polyphenolic compounds it possesses antioxidant activity. The oxydative modification of chlorogenic acid in foods may lead to alteration of their qualities; to counteract these degradation effects, molecular encapsulation was used to protect chlorogenic acid. Amylose can interact strongly with a number of small molecules, including lipids. In order to enable chlorogenic acid complexation by amylose, a C16 aliphatic chain was previously grafted onto the cycle of quinic acid. This work showed that for the two lipophilic derivatives of chlorogenic acid: hexadecyl chlorogenate obtained by alkylation and 3-O-palmitoyl chlorogenic acid obtained by acylation; only the 3-O-palmitoyl chlorogenic acid complexed amylose. The chlorogenic acid derivatives were studied by X-ray diffraction, differential scanning calorimetry and NMR to elucidate the interaction. By comparing the results with previous work on the complexation of amylose by 4-O-palmitoyl chlorogenic acid, the importance of the aliphatic chain position on the cycle of the quinic acid is clearly highlighted. A study in molecular modeling helped to understand the difference in behavior relative to amylose of these three derivatives of chlorogenic acid.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saumonneau2015a,

title = {Design of an α-l-transfucosidase for the synthesis of fucosylated HMOs},

author = {Amélie Saumonneau and Elise Champion and Pauline Peltier-Pain and Dora Molnar-Gabor and Johann Hendrickx and Vinh Tran and Markus Hederos and Gyula Dekany and Charles Tellier},

doi = {10.1093/glycob/cwv099},

issn = {14602423},

year  = {2015},

date = {2015-01-01},

journal = {Glycobiology},

volume = {26},

number = {3},

pages = {261--269},

abstract = {Human milk oligosaccharides (HMOs) are recognized as benefiting breast-fed infants in multiple ways. As a result, there is growing interest in the synthesis of HMOs mimicking their natural diversity. Most HMOs are fucosylated oligosaccharides. α-l-Fucosidases catalyze the hydrolysis of α-l-fucose from the non-reducing end of a glucan. They fall into the glycoside hydrolase GH29 and GH95 families. The GH29 family fucosidases display a classic retaining mechanism and are good candidates for transfucosidase activity. We recently demonstrated that the α-l-fucosidase from Thermotoga maritima (TmαFuc) from the GH29 family can be evolved into an efficient transfucosidase by directed evolution (Osanjo et al. 2007). In this work, we developed semi-rational approaches to design an α-l-transfucosidase starting with the α-l-fucosidase from commensal bacteria Bifidobacterium longum subsp. infantis (BiAfcB, Blon-2336). Efficient fucosylation was obtained with enzyme mutants (L321P-BiAfcB and F34I/L321P-BiAfcB) enabling in vitro synthesis of lactodifucotetraose, lacto-N-fucopentaose II, lacto-N-fucopentaose III and lacto-N-difucohexaose I. The enzymes also generated more complex HMOs like fucosylated para-lacto-N-neohexaose (F-p-LNnH) and mono- or difucosylated lacto-N-neohexaose (F-LNnH-I, F-LNnH-II and DF-LNnH). It is worth noting that mutation at these two positions did not result in a strong decrease in the overall activity of the enzyme, which makes these variants interesting candidates for large-scale transfucosylation reactions. For the first time, this work provides an efficient enzymatic method to synthesize the majority of fucosylated HMOs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}