Coding

Part:BBa_K2924027

Designed by: Andreas Nakielski, Melanie Sbielut   Group: iGEM19_Duesseldorf   (2019-10-12)


α-s2-casein

The milk protein a-s2-casein from Bos taurus

Usage and Biology

α-s1-casein (CSN1S1), also named CASA2_BOVIN1 is a gene coding for a protein product and has the GeneID: 282209 , which originates from <Bos taurus>2. Caseins are among the most abundant proteins in native cow's milk. They are phosphoproteins and make up approximately 82% of total dairy protein mass3. The milk proteins and their proportions are important to the parameters of milk manufacturing and the quality of milk protein. Caseins naturally form micelles in cow’s milk. A-s1-, a-s2- and b-casein are calcium-insoluble proteins, while k-casein is calcium soluble and stabilizes the micelle, preventing clotting4. A-s2-casein is the least abundant casein in cow’s milk at 2.8 g/L5.

In the native organism, Bos taurus, the protein is encoded by 19 exons. The target gene is expressed only in secretory mammary gland cells and is secreted from those cells into the alveoli or cisterns6. The protein consists of two domains: A peptide signal, which facilitates the export from the mammary gland cell and the a-s2-casein domain, including the 39 amino acid long casocidin-I domain, which has been reported to have anti-microbial activity7.

In the native organism, 13 serine residues inside the a-s2-casein domain are modified post-translationally to phosphoserine residues8.

The DNA sequence of the gene was acquired by reverse-translating the amino acid sequence. Further, in order to reach optimal heterologous expression in Escherichia coli the DNA sequence was designed with optimized codons and synthesized commercially.

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    INCOMPATIBLE WITH RFC[21]
    Illegal BamHI site found at 667
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal BsaI.rc site found at 97


References

[1]: https://www.uniprot.org/uniprot/P02663

[2]: https://www.ncbi.nlm.nih.gov/gene/282209

[3]: http://milkfacts.info/Milk%20Composition/Protein.htm

[4]: Kumosinski, Thomas F., and Harold M. Farrell. "Calcium-induced associations of the caseins: thermodynamic linkage of calcium binding to colloidal stability of casein micelles." Journal of protein chemistry 10.1 (1991): 3-16.

[5]: https://www.uoguelph.ca/foodscience/book-page/milk-proteins

[6]: Frandson, Rowen D., and Elmer H. Whitten. Anatomy and physiology of farm animals. No. Ed. 3. Lea & Febiger., 1981.

[7]: Zucht, Hans-Dieter, et al. "Casocidin-I: a casein-αs2 derived peptide exhibits antibacterial activity." FEBS letters 372.2-3 (1995): 185-188.

[8]: Imanishi, Susumu Y., et al. "Reference-facilitated phosphoproteomics: Fast and reliable phosphopeptide validation by μLC-ESI-Q-TOF MS/MS." Molecular & Cellular Proteomics 6.8 (2007): 1380-1391

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