Assessing protein-lipid interactions with a low-cost, accessible centrifugation assay

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• Assessing protein insertion and membrane association is crucial for understanding protein folding, structure, and applications.
• Traditional ultracentrifugation methods for membrane protein analysis are time-consuming and not suitable for low-resource settings.

Purpose of the Study:

• To develop an accessible, cost-effective method for purifying vesicle-integrated cell-free expressed proteins.
• To separate proteoliposomes from unincorporated proteins and lysed membranes using a table-top microcentrifuge and sucrose gradient.

Main Methods:

• Utilized a table-top microcentrifuge (up to 21,130 × g) and sucrose gradient centrifugation.
• Developed a purification protocol to isolate vesicle-integrated proteins from cell-free expression mixtures.
• Validated the method for various protein types, including peripheral, transmembrane, and lipid-specific proteins.

Main Results:

• Successfully purified vesicle-integrated cell-free expressed proteins.
• Demonstrated effective separation of proteoliposomes from unincorporated proteins and cellular debris.
• Validated the method's applicability to proteins from both cell-free systems and cellular membranes.

Conclusions:

• The developed method provides an accessible and cost-effective alternative for isolating proteoliposomes.
• This approach facilitates the study of membrane protein association for biophysical research and cell-free protein applications.
• The technique is versatile and applicable to a range of membrane proteins and expression systems.