Unraveling the Tether: Exploring Representative Protein Linkers and Their Structural and Thermodynamical Properties

Area of Science:

• Protein structure and dynamics
• Biophysical chemistry
• Computational biology

Background:

• Linker peptides connect protein domains, influencing overall protein structure and function.
• Understanding linker behavior is crucial for protein engineering and drug design.

Purpose of the Study:

• To investigate the thermodynamic and structural properties of isolated linker peptides.
• To analyze conformational dynamics of glycine-serine (GS), glycine-glycine (GG), and alanine-proline (AP) linkers.
• To elucidate the role of linker composition and length on protein architecture.

Main Methods:

• Extensive molecular dynamics (MD) simulations.
• Free energy perturbation (FEP) analyses.
• Characterization of free energy landscapes, entropic properties, and solvation energetics for 20 linkers.

Main Results:

• A linear relationship was observed between linker length and thermodynamic contributions (ZPVE, potential energy, entropy).
• Vibrational entropy was identified as a key stabilizing factor.
• AP linkers showed more rigid, extended conformations than flexible GS and GG linkers.

Conclusions:

• Linker composition significantly impacts multidomain protein architecture and dynamics.
• Thermodynamic forces play a critical role in shaping linker conformational behavior.
• Findings provide insights for designing peptide-based systems and modulating protein flexibility.