C-terminal 13-residue truncation induces compact trigger factor conformation and severely impairs its dimerization...

Area of Science:

• Molecular Biology
• Biochemistry
• Structural Biology

Background:

• Trigger factor (TF) is a primary bacterial chaperone involved in nascent polypeptide folding.
• TF exists in three states: ribosome-bound monomer, free monomer, and cytoplasmic dimer.
• TF has distinct domains: N-terminal ribosome binding, middle PPIase, and C-terminal substrate binding/dimerization domains.

Purpose of the Study:

• To investigate the role of the C-terminal 13 residues in TF structure and function.
• To understand how truncating these residues affects TF's stability and chaperone activity.

Main Methods:

• Small-angle X-ray scattering (SAXS) to analyze TF conformation.
• Fluorescence measurements to assess structural changes.
• Limited proteolysis to probe protein stability.
• Biochemical assays to evaluate dimerization and function.

Main Results:

• Deletion of the C-terminal 13 residues induced a more compact TF conformation.
• TF dimerization was significantly reduced in the truncated mutant (TF419).
• Structural stability and chaperone function were impacted by the C-terminal truncation.

Conclusions:

• The C-terminal 13 residues are essential for maintaining TF's structural integrity and stability.
• These residues play a key role in TF dimerization, influencing its overall chaperone mechanism.
• Understanding the C-terminal region's function provides insights into bacterial protein folding regulation.