Iterative In Situ Click Chemistry Creates Antibody-like Protein-Capture Agents

摘要

Most protein-detection methods rely upon antibody-based capture agents. A high-quality antibody exhibits high affinity and selectivity for its cognate protein. However, antibodies are expensive and can be unstable towards dehydration, pH variation, thermal shock, and many other chemical and biochemical processes. Several alternative protein-capture agents, including oligonucleotide aptamers and phage-display peptides, have been reported, each of which has advantages as well as significant limitations. A further alternative is the use of one-bead-one-compound (OBOC) peptide or peptide-mimetic libraries. An advantage of OBOC libraries is that chemical stability, water solubility, and other desired properties may be designed into the compounds. However, OBOC libraries contain typically only 10~4-10~6 elements, and so significant trade-offs are made between peptide length and library chemical diversity. Herein we report the use of in situ click chemistry as a screening approach towards the construction of multi-ligand protein-capture agents (Scheme 1). We harnessed the method to produce a triligand capture agent against human and bovine carbonic anhydrase II (h(b)CAII) as a model system.