Streptavidin is a tetrameric structure, composed of four monomer units which binds firmly to biotin. Each monomer subunit consists of eight twisted antithetical beta strands, forming tertiary barrel structures. It is widely used in molecular biology due to its unique high affinity for the vitamin biotin. The dissociation constant of the biotin-streptavidin complex is approximately ~10^-15 mol/L.

Streptavidin is widely used as a linker in biotechnology as it forms a very stable bond under well-preserved biological conditions. It exhibits a high binding affinity for biotin. This feature makes streptavidin a very efficient and versatile tool for novel sensor development. The streptavidin-biotin system is also used in detection, labeling, and drug delivery.

Application:
Streptavidin exhibits a strong affinity for biotin, forming a non-covalent yet robust interaction—ideal for WB, ELISA, and IHC detection systems.