Cysteine‐Selective Phosphonamidate Electrophiles for Modular Protein Bioconjugations

• Published in: Angewandte Chemie International Edition Vol. 58; no. 34; pp. 11625 - 11630
• Main Authors: Kasper, Marc‐André, Glanz, Maria, Stengl, Andreas, Penkert, Martin, Klenk, Simon, Sauer, Tom, Schumacher, Dominik, Helma, Jonas, Krause, Eberhard, Cardoso, M. Cristina, Leonhardt, Heinrich, Hackenberger, Christian P. R.
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 19.08.2019; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Adducts; Antibodies; bioconjugation; bioorganic chemistry; bioorthogonal chemistry; Chemistry; Chemistry, Multidisciplinary; Construction; Cysteine; cysteine-selective modification; Physical Sciences; Protein biosynthesis; protein modification; Protein synthesis; Proteins; Science & Technology; bioconjugation; cysteine-selective modification; REAGENTS; bioorganic chemistry; PHOSPHONITES; STABILITY; protein modification; CHEMISTRY; bioorthogonal chemistry; CHEMICAL-MODIFICATION; CONTAINING PEPTIDES
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201814715

We describe a new technique in protein synthesis that extends the existing repertoire of methods for protein modification: A chemoselective reaction that induces reactivity for a subsequent bioconjugation. An azide‐modified building block reacts first with an ethynylphosphonite through a Staudinger‐phosphonite reaction (SPhR) to give an ethynylphosphonamidate. The resulting electron‐deficient triple bond subsequently undergoes a cysteine‐selective reaction with proteins or antibodies. We demonstrate that ethynylphosphonamidates display excellent cysteine‐selective reactivity combined with superior stability of the thiol adducts, when compared to classical maleimide linkages. This turns our technique into a versatile and powerful tool for the facile construction of stable functional protein conjugates. Staudinger—Ready—Go! Ethynylphosphonamidates can be chemoselectively incorporated into a given molecule through a Staudinger‐phosphonite reaction, and they react specifically with cysteine residues on proteins to give thiol adducts that are stable under physiological conditions. This enables the facile fusion of complex molecules to proteins.