Personne : Biron, Éric
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Université Laval. Faculté de pharmacie
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- PublicationAccès libreToward solid-phase peptide fragment ligation by a traceless-Ugi multicomponent reaction approach(Royal Society of Chemistry, 2016-11-14) Biron, Éric; Jobin, Steve; Galindo, Sindy-Marcela; Vézina-Dawod, Simon; Fontaine, Alexia; Liang, XinxiaA new methodology to couple peptide fragments on solid support using a traceless isocyanide-based multicomponent reaction is described. The approach uses a microwave-assisted on-resin Ugi four-component reaction to attach a carboxyl free peptide to a supported peptide bearing a free N-terminal amine via the formation of an N-protected amide bond at the ligation site. Afterward, the generated backbone amide protecting group can be efficiently removed by microwave-assisted acidolysis with trifluoroacetic acid to afford a fully deprotected peptide. This straightforward Ugi reaction/deprotection approach was applied to condense various fragment lengths and provided a variety of oligopeptides.
- PublicationRestreintPractical ring-opening strategy for the sequence determination of cyclic peptides from one-bead-one-compound libraries(American Chemical Society, 2013-09-26) Girard, Anick; Biron, Éric; Liang, XinxiaThe use of cyclic peptides in one-bead-one-compound libraries is limited by difficulties in sequencing hit compounds. Lacking a free N-terminal amine, such peptides cannot be sequenced by the Edman degradation approach, and complex fragmentation patterns are obtained by tandem mass spectrometry. To overcome this problem, we designed an alternative approach introducing a methionine residue within the macrocycle and as a linker to allow simultaneous ring-opening and release from the resin upon treatment with cyanogen bromide. The methionine linker was inverted relative to the peptide chain to allow the synthesis of cyclic peptides anchored by a lysine side chain and to avoid the presence of two C-terminal homoserine lactones on the released linear peptides. After MALDI-TOF MS/MS analysis, the peptides released from a single bead were sequenced manually and with a de novo sequencing software. The strategy described herein is compatible with commonly used amino acids and allows sequencing of cyclic peptides in one-bead-one-compound libraries, thus reducing the need for encoding.
- PublicationAccès libreMachine learning assisted design of highly active peptides for drug discovery(Public Library of Science, 2015-04-07) Tremblay, Denise; Biron, Éric; Giguère, Sébastien; Moineau, Sylvain; Laviolette, François; Liang, Xinxia; Marchand, Mario; Corbeil, JacquesThe discovery of peptides possessing high biological activity is very challenging due to the enormous diversity for which only a minority have the desired properties. To lower cost and reduce the time to obtain promising peptides, machine learning approaches can greatly assist in the process and even partly replace expensive laboratory experiments by learning a predictor with existing data or with a smaller amount of data generation. Unfortunately, once the model is learned, selecting peptides having the greatest predicted bioactivity often requires a prohibitive amount of computational time. For this combinatorial problem, heuristics and stochastic optimization methods are not guaranteed to find adequate solutions. We focused on recent advances in kernel methods and machine learning to learn a predictive model with proven success. For this type of model, we propose an efficient algorithm based on graph theory, that is guaranteed to find the peptides for which the model predicts maximal bioactivity. We also present a second algorithm capable of sorting the peptides of maximal bioactivity. Extensive analyses demonstrate how these algorithms can be part of an iterative combinatorial chemistry procedure to speed up the discovery and the validation of peptide leads. Moreover, the proposed approach does not require the use of known ligands for the target protein since it can leverage recent multi-target machine learning predictors where ligands for similar targets can serve as initial training data. Finally, we validated the proposed approach in vitro with the discovery of new cationic antimicrobial peptides.
- PublicationAccès libreConvenient two-step synthesis of highly functionalized benzo-fused 1,4-diazepin-3-ones and 1,5-diazocin-4-ones by sequential Ugi and intramolecular SNAr reactions(Pergamon Press, 2017-09-18) Biron, Éric; Vézina-Dawod, Simon; Liang, Xinxia; Gerber, NicolasBenzodiazepinones are an important family of heterocycles with very attractive pharmacological properties and peptidomimetic abilities. We report herein a rapid and efficient two-step synthesis of polysubstituted 1,4-benzodiazepin-3-ones and 1,5-benzodiazocin-4-ones using a multicomponent condensation/cyclization strategy. The approach uses an Ugi four-component reaction to condense readily available Nα-Fmoc-amino acids, amines and isocyanides with a 2-fluorobenzaldehyde derivative followed by a one-pot Fmoc-group removal, intramolecular aromatic nucleophilic substitution for ring closure and side chain deprotection. The described method gives access to benzo-fused 7- and 8-membered rings bearing a wide variety of functionalized substituents and was applied to efficiently prepare tri- and tetrasubstituted 1,4-benzodiazepin-3-ones and 1,5-benzodiazocin-4-ones in high yields in two straightforward steps.
- PublicationAccès libreOne-pot photochemical ring-opening/cleavage approach for the synthesis and decoding of cyclic peptide libraries(American Chemical Society, 2016-02-25) Biron, Éric; Porte, Karine; Vézina-Dawod, Simon; Bédard, François; Liang, XinxiaA novel dual ring-opening/cleavage strategy to determine the sequence of cyclic peptides from one bead, one compound libraries is described. The approach uses a photolabile residue within the macrocycle and as a linker to allow a simultaneous ring opening and cleavage from the beads upon UV irradiation and provide linearized molecules. Cyclic peptides of five to nine residues were synthesized and the generated linear peptides successfully sequenced by tandem mass spectrometry.