Streptavidin

Streptavidin
Monomeric streptavidin (ribbon diagram) with bound biotin (spheres); PDB: 1STP
Identifiers
OrganismStreptomyces avidinii
Symbol?
UniProtP22629
Search for
StructuresSwiss-model
DomainsInterPro

Streptavidin /ˌstrɛpˈtævɪdɪn/ is a 52 kDa protein (tetramer) purified from the bacterium Streptomyces avidinii. Streptavidin homo-tetramers have an extraordinarily high affinity for biotin (also known as vitamin B7 or vitamin H). With a dissociation constant (Kd) on the order of ≈10−14 mol/L,[1] the binding of biotin to streptavidin is one of the strongest non-covalent interactions known in nature. Streptavidin is used extensively in molecular biology and bionanotechnology due to the streptavidin-biotin complex's resistance to organic solvents, denaturants (e.g. guanidinium chloride), detergents (e.g. SDS, Triton X-100), proteolytic enzymes, and extremes of temperature and pH.

  1. ^ Green NM (1975). "Avidin". Advances in Protein Chemistry. 29: 85–133. doi:10.1016/s0065-3233(08)60411-8. ISBN 9780120342297. PMID 237414.