Oral Presentation 11th Australian Peptide Conference 2015

 Labeling and conjugation of furan modified peptides and proteins under physiological conditions  (#21)

Eirini Antonatou 1 , Willem Vannecke 1 , Kurt Hoogewijs 1 , Annemieke Madder 1
  1. Department of Organic and Macromolecular Chemistry / Organic and Biomimetic Chemistry Research Group, Ghent University, Ghent, Belgium

Site-specific chemical modification of proteins is crucial for understanding protein structure and interactions as well as providing insights into cellular events.[1] In continuation of previous work conducted in our lab in the area of furan-mediated nucleic acid crosslinking,[2] and solid phase-based peptide labeling,[3] in this study, we investigated singlet oxygen (1O2) mediated furan-based peptide labeling in physiological aqueous solutions. Furan-containing peptides were subjected to standard oxidative conditions (air, light, photosensitiser) so that the reactive electrophilic species were generated. These reactive intermediates were intercepted by α-effect nucleophiles to form stable conjugates. Incorporation of nucleophilic fluorophores through a cascade reaction sequence, led to the efficient construction of site-selectively labeled fluorescent peptides.[4]

Furan-peptides bearing sensitive residues such as tryptophan, methionine and histidine as well as a cell-penetrating peptide were subjected to the newly developed oxidation and labeling protocol. Fluorophores of different properties in terms of water solubility, pH sensitivity and fluororescence intensity were tested for their capacity to efficiently label model peptides and proteins. Labeling with Alexa dye proclaims that our methodology could be suitable for biological applications. In summary, a novel methodology has been developed which transforms furan-modified peptides and proteins to fluorescent probes in a single operation in solution, thus enlarging the toolbox of bio-orthogonal conjugations.

We further demonstrate the application of the furan-oxidation chemistry in target identification of peptide ligands recognized by cell-surface receptors.[5]

  1. E. M. Sletten, C. R. Bertozzi, Angew. Chem. Int. Ed. 2009, 48, 6974 .
  2. a) K. Stevens, A. Madder, Nucleic Acids Research 2009, 1555; b) M. Op de Beeck, A. Madder, J. Amer. Chem. Soc. 2011, 796; c) M. Op de Beeck, A. Madder, J. Amer. Chem. Soc. 2012, 10737.
  3. a) A. Deceuninck, A. Madder, Chem. Commun. 2009, 340; b) K. Hoogewijs, D. Buyst, J.M. Winne, J.C. Martins, A. Madder, Chem. Comm. 2012, 2927.
  4. E. Antonatou, K. Hoogewijs, A. Baudot, D. Kalaitzakis, G. Vassilikogiannakis, A.Madder, manuscript submitted.
  5. W. Vannecke, M. Van Troys, C. Ampe, A. Madder, manuscript submitted.