| Source: |
Escherichia coli. |
| Molecular Weight: |
Approximately 4.5 kDa, a single non-glycosylated polypeptide chain containing 41 amino acids. |
| AA Sequence: |
KKVYNAVSCM TNGGICWLKC SGTFREIGSC GTRQLKCCKK K |
| Purity: |
> 95% by SDS-PAGE and HPLC analyses. |
| Biological Activity: |
Fully biologically active when compared to standard. Measured by its antimicrobial activity against E. coli. The ED50 for this effect is typically 4-20 μg/mL. |
| Physical Appearance: |
Sterile filtered white lyophilized (freeze-dried) powder. |
| Formulation: |
Lyophilized from a 0.2 μm filtered concentrated solution in PBS, pH7.4. |
| Endotoxin: |
Less than 1 EU/μg of rRtBD-3 as determined by LAL method. |
| Reconstitution: |
Centrifuge the vial briefly before opening to ensure that the contents settle at the bottom. Reconstitute the vial with sterile distilled water or an aqueous buffer containing 0.1% BSA to achieve a concentration of 0.1-1.0 mg/mL. Divide the resulting stock solution into working aliquots and store them at or below -20°C. For further dilutions, use appropriate buffered solutions. |
| Stability & Storage: |
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70°C as supplied.
1 month, 2 to 8°C under sterile conditions after reconstitution.
3 months, -20 to -70°C under sterile conditions after reconstitution. |
| Synonyms: |
Defensin beta3 |
| Background: |
Defensins, comprising of alpha and beta types, are cationic peptides with antimicrobial properties against Gram-negative and Gram-positive bacteria, fungi and enveloped viruses. These proteins, weighing between 2-6 kDa, play vital roles in the innate immune system. Based on their size and the pattern of their disulfide bonding, mammalian defensins are categorized into alpha, beta, and theta classes. β-Defensins are found in certain leukocytes and on epithelial surfaces. They possess a six-cysteine motif that results in three intra-molecular disulfide bonds. As β-defensins are cationic peptides, they can interact with the membranes of invading microbes, which are negative due to lipopolysaccharides (LPS) and lipoteichoic acid (LTA) present in the cell membrane. Importantly, they bind to the site with higher affinity compared to Ca2+ and Mg2+ ions, impacting the stability of the membrane. In addition to fortifying the innate immune system, they can also boost the adaptive immune system by promoting chemotaxis of monocytes, T-lymphocytes, dendritic cells, and mast cells to the site of infection. |
