Streptavidin Antibodies

Structure of Streptavidin

Streptavidin is a monomeric protein composed of 159 amino acids, forming a typical β -barrel-shaped three-dimensional structure through 8 reverse-parallel β -folded sheets (β1-β8), among which the β3-β4 ring region constitutes a specific biotin binding site. This site is composed of key residues such as Trp79, Trp92 and Asp128. Particularly, Trp120 forms a stable hydrophobic interaction with the biotin-imidazolone ring, endowing it with an extremely strong binding ability. The protein surface is rich in hydrophilic groups, which endows it with good water solubility. The tetramer subunits maintain structural stability through the hydrogen bond network between β -folded sheets, demonstrating excellent heat resistance (able to withstand temperatures up to 80 °C) and resistance to protease degradation. This unique structural feature makes it an indispensable tool protein in the field of biotechnology.

Fig. 1 Apo-SFX structure of streptavidin.¹

Key structural properties of Streptavidin:

• Tetramer β -barrel folded structure
• Each subunit contains a specific biotin binding site
• High-temperature resistant (Tm > 70℃) and extreme pH
• Surface charged residues affect solubility

Functions of Streptavidin

Streptavidin is a tetramer protein with a molecular weight of approximately 52-60kDa, and its monomer molecular weight is about 13-15kDa. This protein shows structural differences among different sources:

Compared with antibody-antigen interactions, the streptavidin-biotin system exhibits unique binding kinetic characteristics: a rapid binding rate and an extremely slow dissociation rate, making it a model of irreversible binding. This characteristic gives it an irreplaceable advantage in molecular immobilization applications that require long-lasting stability.

Applications of Streptavidin and Streptavidin Antibody in Literature

1. Ayan, Esra, et al. "Cooperative allostery and structural dynamics of streptavidin at cryogenic-and ambient-temperature." Communications biology 5.1 (2022): 73. https://doi.org/10.1038/s42003-021-02903-7

This study resolved the high-resolution crystal structures of two non-bound (Apo) states of streptavidin (1.7 A at room temperature SFX and 1.1 A at low temperature freezing). Combined with computational analysis, it reveals that it forms a cooperative allosteric mechanism that simulates biotin binding through a water molecule network, providing new insights into the dynamic structure of this naturally strongest affinity system.

2. Suganuma, Masatoshi, et al. "Mirror-image streptavidin with specific binding to L-biotin, the unnatural enantiomer." Scientific Reports 12.1 (2022): 9568. https://doi.org/10.1038/s41598-022-13763-4

The research team successfully synthesized D-type streptavidin enantiomers, which can specifically bind to L-biotin. This artificial protein was prepared through the synthesis of all-D-amino acid peptides and in vitro folding, maintaining stability and structural characteristics comparable to those of natural streptavidin. This new type of streptavidin can effectively eliminate the interference of D-biotin in serum detection and shows superior performance in detection systems such as Biacore and ELISA, providing an innovative alternative to the biotin-streptavidin system.

3. Pähler, A., et al. "Characterization and crystallization of core streptavidin." Journal of Biological Chemistry 262.29 (1987): 13933-13937.https://doi.org/10.1016/S0021-9258(18)47884-2

The core streptavidin retains its complete biotin-binding activity after being truncated, its solubility is enhanced, and its crystal structure shows a D2-symmetric tetramer. Conformational changes occur when binding to biotin. Currently, the three-dimensional structure of its complex with selenobiotin is being resolved.

4. Zhang, Min, et al. "The crystal structure of monovalent streptavidin." Scientific reports 6.1 (2016): 35915. https://doi.org/10.1038/srep35915

This paper analyzed the 1.7A crystal structure of monovalent streptavidin (a single-site high-affinity binding biotin), and found that the L3,4 loops of its three failed subunits were in an "open state", and the hydrogen bond network involving S52 was stable. Mutations at key sites (N23A/S27D/S45A) further reduce biotin binding capacity by stabilizing the open state, providing a structural basis for rational design.

5. Nödling, Alexander R., et al. "The role of streptavidin and its variants in catalysis by biotinylated secondary amines." Organic & biomolecular chemistry 19.47 (2021): 10424-10431. https://doi.org/10.1039/D1OB01947C

This study combined host screening, crystallography and QM/MM simulation to explore the influence of streptavidin protein structure on the 1, 4-conjugated addition reaction catalyzed by biotinylated secondary amines. It was found that the tetramer T-Sav significantly enhanced the stereoselectivity of the reaction through subunit interface residues, among which Lys121 played a key role in controlling stereoselectivity and reactivity. Although the asymmetric dimer D-Sav has a relatively low conversion rate, it is more suitable for subsequent protein engineering optimization.

Creative Biolabs: Streptavidin Antibodies for Research

Creative Biolabs specializes in the production of high-quality Streptavidin antibodies for research and industrial applications. Our portfolio includes monoclonal antibodies tailored for ELISA, Flow Cytometry, Western blot, immunohistochemistry, and other diagnostic methodologies.

• Custom Streptavidin Antibody Development: Tailor-made solutions to meet specific research requirements.
• Bulk Production: Large-scale antibody manufacturing for industry partners.
• Technical Support: Expert consultation for protocol optimization and troubleshooting.
• Aliquoting Services: Conveniently sized aliquots for long-term storage and consistent experimental outcomes.

For more details on our Streptavidin antibodies, custom preparations, or technical support, please contact us.