Expression and purification of human calbindin D28k

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Chemistry

Background:

• Calbindin D28k is a vital calcium-binding protein found in the mammalian central nervous system and epithelial tissues.
• Its role in calcium transport highlights the need for reliable sources for research.

Purpose of the Study:

• To develop an efficient and scalable protocol for the expression and purification of human calbindin D28k.
• To obtain pure, homogeneous, calcium-loaded calbindin D28k for further studies.

Main Methods:

• Human calbindin D28k was cloned into a Pet3a vector and expressed in Escherichia coli.
• Purification involved heat precipitation, DEAE-cellulose chromatography (with calcium), and DEAE-Sephacel chromatography (with EDTA).
• Protein identity and purity were confirmed using immunoblotting, SDS-PAGE, agarose gel electrophoresis, and 1H NMR spectroscopy.

Main Results:

• A yield of 20-50 mg of pure, homogeneous calcium-loaded calbindin D28k per liter of bacterial culture was achieved.
• The entire expression and purification process was completed in just 3 days.
• The protocol was designed to minimize protein degradation and deamidation.

Conclusions:

• A robust, rapid, and scalable method for producing high-purity human calbindin D28k has been established.
• This protocol facilitates the availability of calbindin D28k for research into its biological functions.
• The method's efficiency and ease of scale-up make it valuable for biochemical and molecular biology applications.