Chemical CLICK-functionalization of recombinant proteins

CLICK-functionalized NHS Ester or Maleimides enable the introduction of an azide-, alkyne-, DBCO-, tetrazine- or trans-cyclooctene-group into recombinant proteins via targeting of lysine groups (NHS Ester-based Amine Labeling) or cysteine groups (Maleimide-based Thiol Labeling) (Tab. 1). The resulting randomly CLICK-functionalized protein can subsequently be processed via Cu(I)-catalyzed (azide-alkyne) or Cu(I)-free (azide-DBCO /tetrazine/TCO) click chemistry that offers the choice

• to introduce a Biotin group for subsequent purification tasks (via Azides of Biotin, Alkynes of Biotin or DBCO-containing Biotinylation reagents)
• to introduce a fluorescent group for subsequent microscopic imaging (via fluorescent Azides, fluorescent Alkynes, DBCO-containing fluorescent dyes or Tetrazine-containing fluorescent dyes)
• to crosslink the protein to complementary CLICK-functionalized biomolecules e.g. DNA

Table 1: Overview of CLICK-functionalized NHS ester and Maleimides for Amino & Thiol Labeling, respectively.