Papers by Laurence Menu-Bouaouiche
HAL (Le Centre pour la Communication Scientifique Directe), Apr 22, 2014
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Jun 20, 2014
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Jun 17, 2011
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), Jun 6, 2011
International audienc
Biochemical and Biophysical Research Communications, Aug 1, 2003
The lectin found in mycelium and sclerotes of the phytopathogenic fungus Sclerotinia sclerotiorum... more The lectin found in mycelium and sclerotes of the phytopathogenic fungus Sclerotinia sclerotiorum is a homodimer consisting of two identical non-covalently bound subunits of 16,000Da. CD spectra analysis revealed that the S. sclerotiorum agglutinin (SSA) contains predominantly β-sheet structures. SSA exhibits specificity towards GalNAc whereby the hydroxyls at positions 4 and 6 of the pyranose ring play a key role
HAL (Le Centre pour la Communication Scientifique Directe), Jun 4, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Jun 25, 2014
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Annals of Botany, Jul 6, 2016
Background and aims Potato (Solanum tuberosum) is an important food crop and is grown worldwide. ... more Background and aims Potato (Solanum tuberosum) is an important food crop and is grown worldwide. It is, however, significantly sensitive to a number of soil-borne pathogens that affect roots and tubers, causing considerable economic losses. So far, most research on potato has been dedicated to tubers and hence little attention has been paid to root structure and function. Methods In the present study we characterized root border cells using histochemical staining, immunofluorescence labelling of cell wall polysaccharides epitopes and observation using laser confocal microscopy. The monosaccharide composition of the secreted exudates was determined by gas chromatography of trimethylsilyl methylglycoside derivatives. The effects of root exudates and secreted arabinogalactan proteins on bacterial growth were investigated using in vitro bioassays. Key Results Root exudate from S. tuberosum was highly enriched in galactose-containing molecules including arabinogalactan proteins as major components. Treatment of the root with an elicitor derived from Pectobacterium atrosepticum, a soil-borne pathogen of potato, altered the composition of the exudates and arabinogalactan proteins. We found that the growth of the bacterium in vitro was differentially affected by exudates from elicited and nonelicited roots (i.e. inhibition versus stimulation). Conclusions Taken together, these findings indicate that galactose-containing polymers of potato root exudates play a central role in root-microbe interactions.
Biochimie, Feb 1, 2003
Fruit-specific thaumatin-like proteins were isolated from cherry, apple and banana, and their enz... more Fruit-specific thaumatin-like proteins were isolated from cherry, apple and banana, and their enzymatic and antifungal activities compared. Both the apple and cherry possess a moderate endo-β1,3-glucanase activity but are devoid of antifugal activity. In contrast, the banana thaumatin-like protein inhibits the in vitro hyphal growth of Verticillium albo-atrum but is virtually devoid of endo-β1,3-glucanase activity. Both structural and molecular modeling studies showed that all three thaumatin-like proteins possess an extended electronegatively charged cleft at their surface, which is believed to be a prerequisite for endo-β1,3-glucanase activity. Docking experiments showed that the positioning of linear (1,3)-β-D-glucans in the cleft of the apple and cherry proteins allows an interaction with the glutamic acid residues that are responsible for the hydrolytic cleavage of the glucan. Due to a different positioning in the cleft of the banana thaumatin-like protein, the linear β-glucans cannot properly interact with the catalytic glutamic acid residues and as a result the protein possesses no enzymatic activity. The possible function of the fruit-specific thaumatin-like proteins is discussed in view of the observed biological activities and structural features.
HAL (Le Centre pour la Communication Scientifique Directe), Apr 10, 2014
International audienc
Advances and applications in bioinformatics and chemistry, Jun 1, 2021
Background: O-GlcNAcylation is an essential post-translational modification (PTM) in mammalian ce... more Background: O-GlcNAcylation is an essential post-translational modification (PTM) in mammalian cells. It consists in the addition of a N-acetylglucosamine (GlcNAc) residue onto serines or threonines by an O-GlcNAc transferase (OGT). Inhibition of OGT is lethal, and misregulation of this PTM can lead to diverse pathologies including diabetes, Alzheimer's disease and cancers. Knowing the location of O-GlcNAcylation sites and the ability to accurately predict them is therefore of prime importance to a better understanding of this process and its related pathologies. Purpose: Here, we present an evaluation of the current predictors of O-GlcNAcylation sites based on a newly built dataset and an investigation to improve predictions. Methods: Several datasets of experimentally proven O-GlcNAcylated sites were combined, and the resulting meta-dataset was used to evaluate three prediction tools. We further defined a set of new features following the analysis of the primary to tertiary structures of experimentally proven O-GlcNAcylated sites in order to improve predictions by the use of different types of machine learning techniques. Results: Our results show the failure of currently available algorithms to predict O-GlcNAcylated sites with a precision exceeding 9%. Our efforts to improve the precision with new features using machine learning techniques do succeed for equal proportions of O-GlcNAcylated and non-O-GlcNAcylated sites but fail like the other tools for real-life proportions where ~1.4% of S/T are O-GlcNAcylated. Conclusion: Present-day algorithms for O-GlcNAcylation prediction narrowly outperform random prediction. The inclusion of additional features, in combination with machine learning algorithms, does not enhance these predictions, emphasizing a pressing need for further development. We hypothesize that the improvement of prediction algorithms requires characterization of OGT's partners.
Analytical Chemistry, May 27, 2015
Isotopic labeling is widely used in various fields like proteomics, metabolomics, fluxomics, as w... more Isotopic labeling is widely used in various fields like proteomics, metabolomics, fluxomics, as well as in NMR structural studies, but it requires an efficient determination of the isotopic enrichment. Mass spectrometry is the method of choice for such analysis. However, when complex expression systems like hairy roots are used for production, multiple populations of labeled proteins may be obtained. If the isotopic incorporation determination is actually well-known for unimodal distributions, the multimodal distributions have scarcely been investigated. Actually, only a few approaches allow the determination of the different labeled population proportions from multimodal distributions. Furthermore, they cannot be used when the number of the populations and their respective isotope ratios are unknown. The present study implements a new strategy to measure the (15)N labeled populations inside a multimodal distribution knowing only the peptide sequence and peak intensities from mass spectrometry analyses. Noteworthy, it could be applied to other elements, like carbon and hydrogen, and extended to a larger range of biomolecules.
Biochemical and Biophysical Research Communications, Apr 1, 2001
The lectin isolated from the phytopathogenic basidiomycete Rhizoctonia solani (RSA) is a homodime... more The lectin isolated from the phytopathogenic basidiomycete Rhizoctonia solani (RSA) is a homodimer of two noncovalently associated monomers of 15.5 kDa. RSA is a basic protein (pI > 9) which consists mainly of -sheets. A presumed relationship with ricin-B is supported by the sequence similarity between the N-terminus of RSA and the N-terminal subdomain of ricin-B. Hydrophobic cluster analysis confirms that the N-terminus of both proteins has a comparable folding. RSA exhibits specificity towards Gal/GalNAc whereby the hydroxyls at the C3, C4, and C6 positions of the pyranose ring play a key role in the interaction with simple sugars. The carbohydrate-binding site of RSA apparently accommodates only a single sugar unit. Our results demonstrate an obvious evolutionary relationship between some fungal and plant lectins, but also provide evidence for the occurrence of a lectin consisting of subunits corresponding to a single subdomain of ricin-B.
Biochimie, 2006
The structure of a thaumatin-like protein from banana (Musa acuminata) fruit, an allergen with an... more The structure of a thaumatin-like protein from banana (Musa acuminata) fruit, an allergen with antifungal properties, was solved at 1.7-A-resolution, by X-ray crystallography. Though the banana protein exhibits a very similar overall fold as thaumatin it markedly differs from the sweet-tasting protein by the presence of a surface exposed electronegative cleft. Due to the presence of this electronegative cleft, the banana thaumatin-like protein (Ban-TLP) acquires a strong (local) electronegative character that eventually explains the observed antifungal activity. Our structural analysis also revealed the presence of conserved residues of exposed epitopic determinants that are presumably responsible for the allergenic properties of banana fruit towards susceptible individuals, and provided evidence that the Ban-TLP shares some structurally highly conserved IgE-binding epitopes with thaumatin-like proteins from fruits or pollen from other plants. In addition, some overlap was detected between the predicted IgE-binding epitopes of the Ban-TLP and IgE-binding epitopes previously identified in the mountain cedar Jun a 3 TLP aeroallergen. The presence of these common epitopes offers a molecular basis for the cross-reactivity between aeroallergens and fruit allergens.
Biochemical Journal, May 8, 2002
Evidence is presented that the specificity of jacalin, the seed lectin from jack fruit (Artocarpu... more Evidence is presented that the specificity of jacalin, the seed lectin from jack fruit (Artocarpus integrifolia), is not directed exclusively against the T-antigen disaccharide Galβ1,3GalNAc, lactose and galactose, but also against mannose and oligomannosides. Biochemical analyses based on surface-plasmon-resonance measurements, combined with the X-ray-crystallographic determination of the structure of a jacalin-α-methyl-mannose complex at 2 A H resolution, demonstrated clearly that jacalin is fully capable of binding mannose. Besides mannose, jacalin also interacts readily with glucose, N-acetylneuraminic acid and N-acetylmuramic
HAL (Le Centre pour la Communication Scientifique Directe), Jun 17, 2011
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), May 16, 2014
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), May 17, 2015
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