Quantitative solubilization of nonhistone chromosomal proteins without denaturation using zwitterionic detergents

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Zwitterionic detergents are crucial tools in molecular biology for protein solubilization and extraction.
• Understanding the differential properties of detergents like SB 12 and Chaps is essential for optimizing nuclear protein studies.

Purpose of the Study:

• To compare the efficacy and selectivity of three commercial zwitterionic detergents (SB 12, SB 14, and Chaps) for nuclear protein extraction.
• To evaluate the impact of these detergents on protein solubility, enzyme activity, and histone/nonhistone protein extraction.

Main Methods:

• Comparative analysis of SB 12, SB 14, and Chaps for protein solubilization efficiency across a pH range (6-9).
• Quantification of total protein solubilization from rat liver nuclei at specific ionic strength (I=0.35) and detergent concentration (1%).
• Assessment of core histone and nonhistone protein extraction using Chaps versus SB 12.
• Evaluation of the effects of detergents on DNA-dependent RNA polymerase and isopeptidase activities.

Main Results:

• SB 12 and Chaps demonstrated higher utility than SB 14 due to solubility and assay compatibility.
• SB 12 exhibited greater protein solubilization efficiency (approx. 70%) compared to Chaps (approx. 47%) from rat liver nuclei at pH 9, I=0.35.
• Chaps extracted core histones to a lesser extent than SB 12.
• While 1% Chaps minimally affected DNA-dependent RNA polymerase and isopeptidase activities, 0.3% SB 12 inhibited isopeptidase activity.

Conclusions:

• SB 12 is highly effective for the comprehensive solubilization of whole nuclear proteins.
• Chaps is suitable for the selective extraction of nonhistone chromosomal proteins, preserving their native activity.
• The choice of zwitterionic detergent depends on the specific research objective: broad solubilization versus selective extraction of nuclear protein fractions.