Structural stability of E. coli trigger factor studied by synchrotron small-angle X-ray scattering

Area of Science:

• Biophysics
• Structural Biology
• Protein Science

Background:

• Escherichia coli trigger factor (TF) is a crucial molecular chaperone involved in protein folding.
• Understanding TF's structural dynamics and stability is key to elucidating its chaperone mechanism.

Purpose of the Study:

• To investigate the structural characteristics and urea-induced unfolding transitions of full-length TF and its mutants.
• To determine the role of different TF domains in its overall stability and conformation.

Main Methods:

• Solution small-angle X-ray scattering (SAXS) was employed to analyze protein structure.
• Radii of gyration (Rg), distance-distribution function (P(r)), and integrated intensity were measured for TF variants.
• Urea-induced unfolding was monitored to assess protein stability.

Main Results:

• The C-terminal truncated mutant (TF360) showed significant structural differences and reduced stability compared to full-length TF.
• The N-domain truncated mutant (MC) maintained a compact structure but exhibited decreased stability.
• SAXS data provided quantitative measures of compactness and shape changes during unfolding.

Conclusions:

• The C-terminal region of TF is essential for maintaining its structural integrity and conformational stability.
• The N-domain contributes to stability but appears relatively independent of the C-terminal region's influence.
• These findings highlight the domain-specific contributions to TF's function and stability.