title: A three-component Mannich-type reaction for selective tyrosine bioconjugation.
abstract: A new selective bioconjugation reaction is described for the modification of tyrosine residues on protein substrates. The reaction uses imines formed in situ from aldehydes and electron-rich anilines to modify phenolic side chains through a Mannich-type electrophilic aromatic substitution pathway. The reaction takes place under mild pH and temperature conditions and can modify protein substrates at concentrations as low as 20 muM. Using an efficient fluorescence-based assay, we demonstrated the reaction using a number of aldehydes and protein targets. Importantly, proteins lacking surface-accessible tyrosines remained unmodified. It was also demonstrated that enzymatic activity is preserved under the mild reaction conditions. This strategy represents one of the first carbon-carbon bond-forming reactions for protein modification and provides an important complement to more commonly used lysine- and cysteine-based methods.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
authors.forename: Neel S
authors.initials: NS
authors.lastname: Joshi
authors.forename: Leanna R
authors.initials: LR
authors.lastname: Whitaker
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Francis
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000814:Aniline Compounds / Q000737:chemistry*; D002919:Chymotrypsinogen / Q000737:chemistry; D005557:Formaldehyde / Q000737:chemistry; D009113:Muramidase / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D012260:Ribonucleases / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D000447:Aldehydes; D000814:Aniline Compounds; D009211:Myoglobin; D011506:Proteins; D005557:Formaldehyde; D014443:Tyrosine; D002919:Chymotrypsinogen; D012260:Ribonucleases; D009113:Muramidase