Samy Cecioni

Samy Cecioni
Université de Montréal | UdeM · Department of Chemistry

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46
Publications
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2,445
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Publications

Publications (46)
Article
Glycan recognition by glycan‐binding proteins is central to the biology of all living organisms. The efficient capture and characterization of relatively weak non‐covalent interactions remains an important challenge in various fields of research. Photoaffinity labeling strategies can create covalent bonds between interacting partners, and photoacti...
Article
Full-text available
Glycan recognition by glycan‐binding proteins is central to the biology of all living organisms. The efficient capture and characterization of relatively weak non‐covalent interactions remains an important challenge in various fields of research. Photoaffinity labeling strategies can create covalent bonds between interacting partners, and photoacti...
Article
Full-text available
Understanding the function and regulation of enzymes within their physiologically relevant milieu requires quality tools that report on their cellular activities. Here we describe a strategy for glycoside hydrolases that overcomes several limitations in the field, enabling quantitative monitoring of their activities within live cells. We detail the...
Article
Hundreds of nuclear, cytoplasmic, and mitochondrial proteins within multicellular eukaryotes have hydroxyl groups of specific serine and threonine residues modified by the monosaccharide N-acetylglucosamine (GlcNAc). This modification, known as O-GlcNAc, has emerged as a central regulator of both cell physiology and human health. A key emerging fun...
Article
Calix[4]arenes are unique macrocycles that through judicious functionalisation at the lower-rim can be either fixed in one of four conformations or remain conformationally flexible. Introduction of propynyl or propenyl groups unexpectedly provides a new possibility; a unidirectional conformational switch, with the 1,3-alternate and 1,2-alternate co...
Article
Full-text available
Cell active inhibitors of glycoside processing enzymes are valuable research tools that help us understand the physiological roles of this diverse class of enzymes. endo-N-Acetylglucosaminidases have gained increased attention for their important roles in both mammals and human pathogens; however, metabolically stable cell active inhibitors of thes...
Article
Tunable Förster resonance energy transfer (FRET)-quenched substrates are useful for monitoring the activity of various enzymes within their relevant physiological environments. Development of FRET-quenched substrates for exo-glycosidases, however, has been hindered by their constrained pocket-shaped active sites. Here we report the design of a new...
Article
N-Acetylglucosamine β-O-linked to nucleocytoplasmic proteins (O-GlcNAc) is implicated in the regulation of gene expression in organisms, from humans to Drosophila melanogaster. Within Drosophila, O-GlcNAc transferase (OGT) is one of the Polycomb group proteins (PcGs) that act through Polycomb group response elements (PREs) to silence homeotic (HOX)...
Article
O-GlcNAc transferase (OGT) catalyzes the installation of N-acetylglucosamine (GlcNAc) O-linked to nucleocytoplasmic proteins (O-GlcNAc) within multicellular eukaryotes. OGT shows surprising tolerance for structural changes in the sugar component of its nucleotide sugar donor substrate, uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). Here we f...
Article
Nucleocytoplasmic glycosylation of proteins with O‐linked N‐acetylglucosamine residues (O‐GlcNAc) is mediated by the glycosyltransferase O‐GlcNAc transferase (OGT). O‐GlcNAc is recognized as a common post‐translational modification and is found on hundreds of proteins within all metazoans studied to date. O‐GlcNAc has emerged as a regulator of dive...
Article
Full-text available
O-glycosylation of the nuclear pore complex (NPC) by O-linked N-acetylglucosamine (O-GlcNAc) is conserved within metazoans. Many nucleoporins (Nups) comprising the NPC are constitutively O-GlcNAcylated, but the functional role of this modification remains enigmatic. We show that loss of O-GlcNAc, induced by either inhibition of O-GlcNAc transferase...
Article
Full-text available
Cycloaddition between (+) or (-)-menthone-derived nitrones and N-benzyl-3-pyrroline afforded enantiopure spiro-fused heterocycles. The reaction occurred enantio- and diastereo-selectively on the less hindered side of the nitrone, the 3-pyrroline N-benzyl group being oriented outwards, thus controlling the configurations of three simultaneously crea...
Patent
Full-text available
The present invention relates to a calixarene-based glycosylated compound (I) having the formula: (I) wherein D is independently selected in the group comprising a —CH2-group, an oxygen atom, a sulphur atom, a sulfinyl group or a sulfonyl group, E is independently selected in the group comprising a hydrogen, an alkyl having from 1 to 10 carbon atom...
Article
Full-text available
Nucleocytoplasmic glycosylation of proteins with O-linked N-acetylglucosamine residues (O-GlcNAc) is recognized as a conserved post-translational modification found in all metazoans. O-GlcNAc has been proposed to regulate diverse cellular processes. Impaired cellular O-GlcNAcylation has been found to lead to decreases in the levels of various prote...
Article
Interacting biomolecules form complex and dynamic information networks that can be understood thanks to thermodynamic and kinetics fundamental principles. The simplest way to represent such an interaction is to consider two biomolecules in dynamic association following Fisher's lock-key concept, the resulting complex being more stable than the two...
Article
Design of multivalent glycoconjugates can find applications such as in anti-adhesive therapy against bacterial infections. Nevertheless, the access to such macromolecules requires functionalized building blocks prepared in a minimum number of steps and on a multi-gram scale at least for the laboratory. Fucose is a representative epitope used by sev...
Patent
The present invention relates to novel pyrrolidine derivatives of formula (I), where R1, R2, R3, R4, R5 and X are as defined in claim 1, optionally in zwitterionic form, in the form of a pure optical isomer, or in the form of a mixture of optical isomers in any proportion, or in a form enriched with an optical isomer, as well as to the pharmaceutic...
Article
Intracellular glycosylation of nuclear and cytoplasmic proteins involves the addition of N-acetylglucosamine (O-GlcNAc) to serine and threonine residues. This dynamic modification occurs on hundreds of proteins and is involved in various essential biological processes. Because O-GlcNAc is substoichiometric and labile, identifying proteins and sites...
Article
A family of fifteen glycoclusters based on a cyclic oligo-(1→6)-β-D-glucosamine core has been designed as potential inhibitors of the bacterial lectin LecA with various valencies (from 2 to 4) and linkers. Evaluation of their binding properties towards LecA has been performed by a combination of hemagglutination inhibition assays (HIA), enzyme-link...
Article
Pseudomonas aeruginosa (PA) is a Gram negative opportunistic pathogen and is the major pathogen encounter in the cystic fibrosis (CF) lung airways. It often leads to chronic respiratory infection despite aggressive antibiotic therapy due to the emergence of resistant strains and to the formation of biofilm. The lectin PA-IIL (LecB) is a fucose-spec...
Article
The design of multivalent glycoclusters requires the conjugation of biologically relevant carbohydrate epitopes functionalized with linker arms to multivalent core scaffolds. The multigram-scale syntheses of three structurally modified triethyleneglycol analogues that incorporate amide moiety(ies) and/or a phenyl ring offer convenient access to a s...
Article
Full-text available
Under microwave activation, the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) between an azido-functionalized lactoside and tetra-alkynylated core scaffolds (one porphyrin and three topological conformers of calix[4]arenes) afforded four lactosylated glycoclusters in high yields. The glycoclusters were then evaluated and compared to a monovale...
Patent
The present invention relates to a calixarene-based glycosylated compd. (I) having the formula : (I) wherein D is independently selected in the group comprising a -CH2 -group, an oxygen atom, a sulfur atom, a sulfinyl group or a sulfonyl group, E is independently selected in the group comprising a hydrogen, an alkyl having from 1 to 10 carbon atoms...
Article
We have used single-walled carbon nanotube field-effect transistor (SWNT-FET) and chemically converted graphene field-effect transistor (CCG-FET) devices to probe the interactions between carbohydrates and their recognition lectins. Porphyrin- and pyrene-based glycoconjugates were used as receptor molecules and the target lectins were two bacterial...
Article
As carbohydrates play a major role in numerous biological processes through their interactions with lectins and also appear as one of the most crucial post-translational modifications of proteins, chemists have developed several approaches for the design of glycoconjugates based on a series of conjugation methodologies. The recent development of co...
Article
Here we investigated the interactions between lectins and carbohydrates using field-effect transistor (FET) devices comprised of chemically converted graphene (CCG) and single-walled carbon nanotubes (SWNTs). Pyrene- and porphyrin-based glycoconjugates were functionalized noncovalently on the surface of CCG-FET and SWNT-FET devices, which were then...
Chapter
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Long gone are the days when synthetic publications included parallel preparative experiments to document reproducibility of the experimental protocols and when journals required such documentation. The new Proven Synthetic Methods Series addresses concerns to chemists regarding irreproducibility of synthetic protocols, lack of characterization data...
Article
Full-text available
Atomic force microscopy reveals that Pseudomonas aeruginosa LecA (PA-IL) and a tetra-galactosylated 1,3-alternate calix[4]arene-based glycocluster self-assemble according to an aggregative chelate binding mode to create monodimensional filaments. Lectin oligomers are identified along the filaments and defects in chelate binding generate branches an...
Article
Influenza neuraminidases hydrolyze the ketosidic linkage between N-acetylneuraminic acid and its adjacent galactose residue in sialosides. This enzyme is a tetrameric protein that plays a critical role in the release of progeny virions. Several methods have been described for the determination of neuraminidase activity, usually based on colorimetri...
Article
Full-text available
Synthetic multivalent glycoclusters show promise as anti-adhesives for the treatment of bacterial infections. Here we report the synthesis of a family of tetravalent galactose and lactose functionalised macrocycles based on the resorcin[4]arene core. The development of diastereoselective synthetic routes for the formation of lower-rim propargylated...
Article
Atomic force microscopy reveals that Pseudomonas aeruginosa LecA (PA-IL) and a tetra-galactosylated 1,3-alternate calix[4]arene-based glycocluster self-assemble according to an aggregative chelate binding mode to create monodimensional filaments. Lectin oligomers are identified along the filaments and defects in chelate binding generate branches an...
Article
Multivalency is playing a major role in biological processes and particularly in lectin-carbohydrate interactions. The design of high-affinity ligands of lectins should provide molecules capable of interfering with these biological processes and potentially inhibit bacterial or viral infections. Azide-alkyne "click" chemistry was applied to the syn...
Article
The design of multivalent glycoconjugates has been developed over the past decades to obtain high-affinity ligands for lectin receptors. While multivalency frequently increases the affinity of a ligand for its lectin through the so-called "glycoside cluster effect", the binding profiles towards different lectins have been much less investigated. We...
Article
We have used single-walled carbon nanotube field-effect transistor (NTFET) devices to probe the interactions between carbohydrates and their recognition proteins called lectins. These interactions are involved in a wide range of biological processes, such as cell-cell recognition, cell-matrix interaction as well as viral and bacterial infections. I...
Article
Following Fischer's "lock-key" concept, non-covalent interactions between a ligand and its receptor is one of the most fundamental process of any biological system. The presence of multiple keys and locks at the surface of many biomolecules leads to multivalent interactions. Lectins are appropriate partners for the study of multivalent interactions...
Article
A novel series of regioregular bithiophene disubstituted with a carbonitrile group as electron acceptor and a hexyl or hexyloxy chain as electron donor, have been synthesized. The position and the regioregularity of substituents on bithiophene have been controlled via a head-to-head (HH) or head-to-tail (HT) coupling reaction to give four monomers:...
Article
Full-text available
Fullerene hexakis-adducts bearing 12 peripheral carbohydrate moieties have been prepared by grafting sugar derivatives onto the fullerene core through the copper mediated Huisgen 1,3-dipolar cycloaddition of azides and alkynes.
Article
A family of seven topologically isomeric calix[4]arene glycoconjugates was prepared through the synthesis of a series of alkyne-derivatised calix[4]arene precursors that are suitable for the attachment of sugar moieties by microwave-assisted copper(I)-catalysed azide-alkyne cycloaddition (CuAAC). The glycoconjugates thus synthesised comprised one m...
Article
Glycosidation of sugar peracetates (D-gluco, D-galacto) with SnCl(4) and CF(3)CO(2)Ag led to either 1,2-cis-, or 1,2-trans-glycosides, depending primarily on the alcohols used. In particular, 1,2-trans-glycosides, expected from acyl-protected glycosyl donors, were formed in high yields with alcohols sharing specific features such as bulkiness, pres...
Article
Full-text available
Glycogen phosphorylase is involved in the hepatic glucose production and appears an emerging biological target for the treatment of type 2 diabetes. Two distinct trivalent inhibitors of GP were synthesized either through Cu(i)-assisted 1,3-dipolar cycloaddition or through formation of a tris-oxadiazole derivative. A biological study of the inhibiti...
Article
Glycosidation of sugar peracetates (d-gluco, d-galacto) with SnCl4 and CF3CO2Ag led to either 1,2-cis-, or 1,2-trans-glycosides, depending primarily on the alcohols used. In particular, 1,2-trans-glycosides, expected from acyl-protected glycosyl donors, were formed in high yields with alcohols sharing specific features such as bulkiness, presence o...

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