Coarse-grained, foldable, physical model of the polypeptide chain

Area of Science:

• Structural Biology
• Biophysics
• Educational Technology

Background:

• Traditional scaled molecular models (e.g., Pauling-Corey) are nonflexible, limiting insights into dynamic biomacromolecular structures.
• Advances in 3D printing and electronics enable the creation of conformationally dynamic physical models.

Purpose of the Study:

• To design, construct, and validate a flexible, scaled physical model of the polypeptide chain.
• To accurately reproduce peptide backbone bond rotational degrees of freedom (ϕ and ψ).
• To incorporate realistic rotational barriers and hydrogen-bonding interactions for stable secondary structure formation.

Main Methods:

• Developed a coarse-grained backbone model with repeating amide and α-carbon units.
• Connected units via mechanical bonds simulating ϕ and ψ angles with realistic rotational barriers.
• Integrated components to represent longer-range hydrogen-bonding interactions.

Main Results:

• The model accurately reproduces bond rotational degrees of freedom in the peptide backbone.
• Incorporated hydrogen bonding facilitates the folding into stable secondary structures.
• The model is constructed from readily obtainable parts.

Conclusions:

• The flexible polypeptide model offers a significant advancement over static models for structural biology research and education.
• It provides an intuitive understanding of chain folding as the basis of macromolecular structure.
• The model serves as a platform for integrating physical models with computational tools for interactive learning.