Exploring single-domain antibody thermostability by molecular dynamics simulation.

Area of Science:

• Biochemistry
• Structural Biology
• Computational Biology

Background:

• Single-domain antibodies, known as nanobodies, are derived from camelid heavy-chain variable regions.
• Experimental data suggests nanobodies possess inherent stability at elevated temperatures.

Purpose of the Study:

• To investigate the thermal stability and dynamics of nanobodies using computational methods.
• To elucidate the molecular mechanisms underlying nanobody thermostability.

Main Methods:

• Molecular dynamics simulations were performed across a range of temperatures.
• Analysis included root mean square deviation (RMSD), native contacts, and solvent-accessible surface area (SASA).
• Thermostability mechanisms were explored via dynamic cross-correlation matrix (DCCM), principal component analysis (PCA), and root mean square fluctuation (RMSF).

Main Results:

• Temperature variations significantly impacted nanobody conformation, as indicated by RMSD, native contacts, and SASA.
• Key stabilizing factors identified include side chain conformations within complementarity-determining region 3 (CDR3).
• Interactions between the CDR3 alpha-helix region and framework 2 were crucial for high-temperature stabilization.

Conclusions:

• Nanobody thermostability is significantly influenced by specific structural features, particularly within CDR3.
• The interplay between CDR3 side chains and framework interactions is critical for maintaining protein integrity at high temperatures.
• These findings provide molecular insights into the design of robust nanobody therapeutics.