Difference between revisions of "Part:BBa K2924029"

Revision as of 15:44, 19 October 2019

κ-casein

kappa-casein from Bos taurus

Usage and Biology

Kappa Casein (CSN3), also named CASK_BOVIN¹, is a gene coding for a protein product, has the GeneID: 281728 and originates from Bos taurus².

Caseins are among the most abundant proteins in native cow's milk. They are phosphoproteins and make up approximately 80% of total dairy protein mass. 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 clotting³. Kappa-casein thus seems to be a very important protein in milk, despite only being present at 3.1 g/L or 9.6% of total protein⁴.

In the native organism, B. taurus, the protein is encoded by 5 exons. The target gene is expressed only in secretory mammary gland cells and is secreted from those cells into the alveoli or cisterns. The protein consists of two domains: A peptide signal, which facilitates the export from the mammary gland cell and the k-casein domain when cleaved. In the native organism, k-casein has four phosphorylated amino acid residues, fewer than the other caseins. However, it also has eight glycosylated amino acid residues, and forms an internal disulfide bond, modifications which do not occur in the other casein proteins¹. These modifications might explain the different solubility of kappa-casein.

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 421
23
COMPATIBLE WITH RFC[23]
25
INCOMPATIBLE WITH RFC[25]
Illegal NgoMIV site found at 102
1000
INCOMPATIBLE WITH RFC[1000]
Illegal SapI.rc site found at 168

References

[1]: https://www.uniprot.org/uniprot/P02668

[2]: https://www.ncbi.nlm.nih.gov/gene/281728

[3]: 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.

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

@@ Line 7: / Line 7: @@
 ===Usage and Biology===
-Kappa Casein (CSN3), also named CASK_BOVIN<sub>1</sup>, is a gene coding for a protein product, has the GeneID: 281728 and originates from <i>Bos taurus</i><sup>2</sup>.
+Kappa Casein (CSN3), also named CASK_BOVIN<sup>1</sup>, is a gene coding for a protein product, has the GeneID: 281728 and originates from <i>Bos taurus</i><sup>2</sup>.
 Caseins are among the most abundant proteins in native cow's milk. They are phosphoproteins and make up approximately 80% of total dairy protein mass. 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 clotting<sup>3</sup>. Kappa-casein thus seems to be a very important protein in milk, despite only being present at 3.1 g/L or 9.6% of total protein<sup>4</sup>.