Alternative binding proteins: affibody binding proteins developed from a small three-helix bundle scaffold

Area of Science:

• Biotechnology
• Protein Engineering

Background:

• Classical antibody-based affinity reagents face competition from novel engineered binding proteins.
• Affibody binding proteins, derived from a small three-helix bundle scaffold, represent a significant class of non-immunoglobulin binding proteins.

Purpose of the Study:

• To review the development and applications of affibody binding proteins.
• To highlight their advantages over traditional antibody reagents.

Main Methods:

• Functional selection from combinatorial libraries of a 6 kDa scaffold domain.
• Characterization of affibody binding proteins for high affinity and diverse target recognition.

Main Results:

• High-affinity affibody binding proteins have been developed for numerous targets over the past decade.
• Applications span bioseparation, diagnostics, functional inhibition, viral targeting, and in vivo tumor imaging/therapy.

Conclusions:

• The small size of affibody binding proteins facilitates chemical synthesis.
• This enables advantageous site-specific introduction of labels and radionuclide chelators for advanced applications.