Stabilized Wittig olefination for bioconjugation

Abstract

Stabilized Wittig olefination holds great potential as a bioconjugation reaction. We demonstrate that the reaction of stabilized phosphorus ylides (or phosphonium salts) with aryl aldehydes is sufficiently robust to be used for live cell affinity isolation and fluorescence tagging of a protein, FKBP12.

Chemoselective and site-selective peptide and native protein modification enabled by aldehyde auto-oxidation

“…Even though a complex combination of multiple parameters is involved, operationally simple front-end protocol would also excite the non-experts. The transformation is efficient in the modification of peptides and structurally diverse proteins with a wide range of Lys residues (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Interception of formylation of protein by a distinct electrophile confirms extended application of this chemical platform.…”

“…The preferential reaction of N α -NH 2 with aldehydes has established the later as a privileged electrophile. The examples include reductive amination, 8 Wittig olefination, 9 Pictet-Spengler ligation, 10 aldehyde capture ligation, 11 imidazolidinone formation, 5a and transamination. 12 On the other hand, it also highlights the extreme challenge involved in the site-selective N ε -NH 2 modification in preference over N α -NH 2 .…”

Advances in Chemical Protein Modification

“…Aside from the aforementioned reactions, the aldehyde moiety can also be used for selective protein modification, generating stable C–C bonds by the Wittig reaction . Moreover, the biocompatibility of such a reaction enables the application of stabilized phosphorus ylides in live cell affinity isolation and fluorescence labeling of proteins (Scheme f) …”

Site-selective incorporation and ligation of protein aldehydes

“…UV-vis analysis, CD analysis, and analysis of the proteins ability to store and release oxygen were performed on unmodified and modified myoglobin samples, confirming that the tertiary structure of the protein was unaffected. 77 Other applications of Wittig olefinations within a bioorthogonal context include the labeling of the FK506 macrolide in aqueous media with biotin and fluorophores (the modified macrolide can then be used to label F506-binding protein FKBP12 with biotin and fluorophores), 100 and the synthesis of alkenes in living tissue. 101…”