Exploring the aggregation propensity of γS-crystallin protein variants using two-dimensional spectroscopic tools

Area of Science:

• Biochemistry
• Structural Biology
• Biophysics

Background:

• Amyloid fibril formation is linked to diseases and biological functions.
• Predicting protein aggregation propensity is a significant challenge in the field.
• γS-crystallin, an eye lens protein, serves as a model for studying fibrillization.

Purpose of the Study:

• To investigate the fibrillization of wild-type and mutant γS-crystallin using combined 2D nuclear magnetic resonance (NMR) and 2D ultraviolet (2DUV) spectroscopy.
• To establish approximate entropy of 2DUV signals as a predictor of protein aggregation propensity.
• To explore the potential of 2DUV spectroscopy for rapid screening of protein variants associated with aggregation diseases.

Main Methods:

• Utilized joint 2D nuclear magnetic resonance (NMR) and 2D ultraviolet (2DUV) spectroscopy to study protein fibrillization.
• Employed approximate entropy analysis of 2DUV signals to quantify signal complexity.
• Correlated 2DUV signal complexity with conformational entropy and aggregation propensity.

Main Results:

• The approximate entropy of 2DUV signals strongly correlates with conformational entropy and protein aggregation propensity.
• Findings were validated against high-resolution NMR experiments and known amyloid fibrils.
• The 2DUV technique demonstrated potential as a complementary method to structural studies.

Conclusions:

• Approximate entropy of 2DUV signals is a reliable indicator of protein aggregation propensity.
• The 2DUV technique offers a faster, more accessible method for screening protein variants.
• This approach can accelerate the characterization of proteins linked to cataract and other amyloid diseases.