Characterization of intrinsically disordered regions through scalar coupling-based solid-state NMR experiments

Area of Science:

• Biochemistry
• Neuroscience
• Structural Biology

Background:

• Abnormal amyloid fibrils are hallmarks of neurodegenerative diseases, causing neuroinflammation and neuronal death.
• Amyloid fibrils possess a rigid cross-β sheet core and a surrounding "fuzzy coat" of intrinsically disordered regions (IDR).
• Structural characterization of the rigid core is advanced, but the disordered IDR remains challenging to study.

Purpose of the Study:

• To apply advanced solid-state NMR techniques for backbone assignment of IDR in amyloid fibrils.
• To elucidate the conformational dynamics of IDR during ligand binding.
• To improve understanding of amyloid fibril structure-function relationships in disease.

Main Methods:

• Utilized two-dimensional (2D) heteronuclear single quantum coherence (HSQC) and three-dimensional (3D) HNCO, HNCA, and HN(CO)CA spectra.
• Employed scalar coupling-based 1H detection magic angle spinning (MAS) ssNMR techniques.
• Focused on backbone assignment of intrinsically disordered regions (IDR) within amyloid fibrils.

Main Results:

• Successfully applied 2D and 3D ssNMR techniques for IDR backbone assignment.
• Demonstrated the feasibility of characterizing disordered protein conformations in amyloid fibrils.
• Established a foundation for studying IDR conformational changes upon ligand interaction.

Conclusions:

• Advanced ssNMR methods provide crucial insights into the structure of IDR in amyloid fibrils.
• This approach facilitates the study of conformational changes relevant to neurodegenerative disease mechanisms.
• Enables further investigation into the role of IDR in amyloid fibril function and ligand interactions.