A simple cell-alignment protocol for sedimentation velocity analytical ultracentrifugation to complement mechanical...

Area of Science:

• Biophysical chemistry
• Analytical chemistry
• Protein characterization

Background:

• Sedimentation velocity analysis in analytical ultracentrifugation is sensitive to experimental variability.
• Cellular alignment to the center of rotation is a primary source of data variability, impacting protein aggregation studies.
• Recent advancements include the development of mechanical and optical alignment tools.

Purpose of the Study:

• To confirm the impact of cell misalignment on bovine serum albumin (BSA) monomer and dimer characterization.
• To evaluate the performance of a mechanical alignment tool.
• To demonstrate the utility of an enhanced manual alignment protocol.

Main Methods:

• Sedimentation velocity analytical ultracentrifugation experiments were performed.
• Bovine serum albumin (BSA) samples were analyzed under varying degrees of cell alignment.
• A mechanical alignment tool and a manual alignment protocol were employed and assessed.

Main Results:

• Misalignment significantly affected the estimated amounts of BSA monomer and dimer, and the BSA dimer's sedimentation coefficient.
• The mechanical alignment tool demonstrated high performance in achieving accurate cell alignment.
• The enhanced manual alignment protocol proved useful, especially when specialized tools are unavailable.

Conclusions:

• Precise cell alignment is critical for accurate sedimentation velocity analysis, particularly for detecting low levels of protein aggregation.
• The validated mechanical alignment tool and the complementary manual protocol offer practical solutions for improving experimental reproducibility.
• These findings enhance the reliability of analytical ultracentrifugation for protein characterization and aggregation studies.