DNA Modulates Structural Transitions and Oligomerization Kinetics of the Functional Amyloid CRES

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Functional amyloids are crucial for physiological processes, but their assembly mechanisms are poorly understood.
• The mouse epididymal lumen features a functional amyloid matrix essential for sperm maturation and host defense.
• Cystatin-related epididymal spermatogenic (CRES) protein is a key component of this matrix, forming structurally diverse amyloids.

Purpose of the Study:

• To investigate the molecular mechanisms regulating the assembly of functional amyloids, specifically CRES.
• To determine how nucleic acids influence the structure and formation of the epididymal amyloid matrix.
• To elucidate the role of DNA binding in CRES oligomerization and functional diversity.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy
• Site-directed mutagenesis
• Biophysical analyses
• DNA-binding assays

Main Results:

• CRES binds double-stranded DNA with high affinity in a sequence-independent manner.
• DNA binding accelerates CRES amyloid formation by increasing local protein concentration and promoting specific oligomerization pathways.
• DNA interacts with the CRES loop region, redirecting oligomerization through the L1 loop and altering assembly kinetics.

Conclusions:

• DNA acts as a regulator of CRES amyloid assembly, influencing both kinetics and pathway selection.
• This nucleic acid-guided amyloidogenesis provides a mechanism for achieving structural and functional diversity in nonpathological amyloids.
• Findings offer a molecular framework for understanding functional amyloid formation and their physiological roles.