Discovery of new chemoselective ligation reactions by High Throughput Screening – ClickScreen

Reactions are conducted in only 20 microliters in 96-well microtiter plates. Each crude reactions are then tested thanks to an immunoassay method that allows for rapid yield calculation of reactions.

Using the above described approach, more than 6000 reactions have already been carried out and screened. Among the discovered reactions 6 are particularly interesting: 5 for synthetic methodology development and a sixth which present a high potential not only for organic synthesis but also for bioconjugation application.

Current work concerns applications of the discovered chemoselective reaction. We are also preparing a new screening campain.

J. Quinton, S. Kolodych, M. Chaumontet, V. Bevilacqua, M-C. Nevers, H. Volland, S. Gabillet, P. Thuéry, C. Créminon, F. Taran. Angew. Chem. Int. Ed. 2012, 51, 6144-6148. (VIP paper)
PROCÉDÉ DE FABRICATION DE PYRAZOLES, NOUVEAUX PYRAZOLES ET LEURS APPLICATIONS. F. Taran, M. Chaumontet, S. Kolodych, E. Rasolofonjatovo. Fr. Demande N°1351146. February 2013
Discovery of chemoselective and biocompatible reactions using a high-throughput immunoassay screening. Sergii Kolodych, Evelia Rasolofonjatovo, Manon Chaumontet, Marie-Claire Nevers, Christophe Créminon, Frédéric Taran*. Angew. Chem. Int. Ed., 2013, 52(46), 12056–12060. VIP paper

The main goal of the proposed research project is to discover new “click” reactions through the use of a high-throughput screening method, called “sandwich immunoassay”, developed in the laboratory. This technique allows the fast evaluation of both reaction efficiencies and chemoselectivities. Indeed we already proved that this technique is a general tool and allows not only to monitor any kind of cross-coupling reaction but also to identify new chemical reactions. The project will essentially be focused on metal-catalyzed cycloaddition reactions. Research efforts are still needed to find new interesting cycloaddition reactions displaying high chemoselectivity and metal catalysts provide new opportunities for high selective cycloadditions. Thus, libraries of dipoles and dipolarophiles will be combined in the presence of putative catalysts, each reactions will be systematically screened for their effectiveness and for their chemoselectivity by our sandwich immunoassay screening method. This immuno-analytical technique is based on the selective binding of two antibodies for particular structural motifs used as tags for reactive functions. Both antibodies can bind simultaneously the coupling product by recognizing two distinct tags previously introduced into the substrates structures. In the first place, we will synthese the tagged reactants by using classical, described procedures. The library of tagged functions will then be used to run a high number of reactions in parallel which will be systematically screened for their ability to form cross-coupling products. After the first screening and identification of the active combinations leading to coupling products, reactions will be run again in the presence of numerous non-tagged chemical functions. This second screening performed again with the sandwich immunoassay will thus select reactions that are unaffected by the presence of other functionalities therefore revealing chemoselective transformations. We will first studied the best systems highlighted by the second high-throughput screening. After LC/MS, GC/MS analysis, each active combination will be reproduced on a larger scale using non tagged reactants for further characterization of reaction products. In addition, and after optimization, we will study the biocompatibility and bioorthogonality of the new chemoselective cycloaddition reactions. The selected bioorthogonal ligation reactions will then be applied to real examples of protein-protein or protein-enzyme ligations.
The approach described in this research project should provide a high number of results allowing a rapid readout of the true potential of new reactions highlighted.