Crystal structure of streptavidin-biotin complex at pH 2.40, illustration - stock illustration

Illustration of the X-ray structure of streptavidin bound to biotin at pH 2.4. Streptavidin is a tetrameric protein known for its extraordinarily strong binding to biotin, a vitamin. The structure reveals how the four subunits are stabilised and resist dissociation even under highly acidic conditions. Biotin sits snugly within each subunit, forming extensive interactions that lock it in place. Understanding this structure helps explain streptavidin’s remarkable stability and its widespread use in biotechnology applications, such as molecular labelling, purification and detection techniques