Prion protein β2-α2 loop conformational landscape.

Area of Science:

• Neuroscience
• Biochemistry
• Computational Biology

Background:

• Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases.
• The prion protein (PrP) undergoes a conformational change from its cellular form (PrPC) to an aggregated scrapie form (PrPSc).
• Understanding PrPC's physiological function and the PrPC-to-PrPSc conversion mechanism is crucial.

Purpose of the Study:

• To characterize the conformational free-energy surface of a specific mouse PrP segment (residues 121-231).
• To investigate the role of the 167-170 loop, including the Y169A variant, in PrP structure and disease susceptibility.
• To provide quantitative insights into the structural transition-related function of the PrP loop.

Main Methods:

• Utilized a combination of Well-Tempered Ensemble (WTE) and Parallel Tempering (PT) schemes.
• Employed Metadynamics (MetaD) simulations to explore the conformational landscape.
• Analyzed an 11-residue polypeptide segment of mouse PrP(121-231), comparing wild-type with the Y169A variant.

Main Results:

• Detailed conformational landscapes of the wild-type and Y169A mouse PrP(121-231) segment were generated.
• The study identified key conformational states and transitions within the analyzed PrP region.
• Quantitative insights into the structural dynamics of the [Formula: see text]2-[Formula: see text]2 loop were obtained.

Conclusions:

• The generated conformational landscapes integrate with existing experimental data on PrP.
• The findings offer a deeper understanding of the structural basis for PrP's role in TSEs.
• This research elucidates the functional significance of the [Formula: see text]2-[Formula: see text]2 loop in prion protein structure and conversion.