Lac repressor purification without inactivation of DNA binding activity

Area of Science:

• Molecular Biology
• Protein Biochemistry

Background:

• The lac repressor protein is crucial for regulating gene expression in bacteria.
• Purification of the lac repressor often leads to loss of its DNA binding activity, hindering research.
• Maintaining the functional integrity of purified proteins is essential for biochemical studies.

Purpose of the Study:

• To develop a purification procedure that prevents inactivation of the lac repressor's DNA binding activity.
• To ensure the lac repressor retains its operator binding affinity after purification.
• To establish a method for long-term storage of active lac repressor.

Main Methods:

• A novel purification protocol was designed to mitigate common causes of lac repressor inactivation.
• Operator binding activity was quantified to assess the efficacy of the new procedure.
• Stability of the purified repressor during frozen storage was evaluated.

Main Results:

• The developed procedure successfully eliminated the inactivation of DNA binding activity.
• The purified lac repressor exhibited 100 +/- 10% operator binding activity.
• The repressor remained stable with no loss of DNA affinity during indefinite frozen storage.

Conclusions:

• A robust method for purifying active lac repressor has been established.
• This procedure overcomes a significant limitation in working with lac repressor.
• The findings facilitate reliable and long-term use of lac repressor in molecular biology applications.