Molecular dynamics simulation study on the structures of fascin mutants

Area of Science:

• Biochemistry and Molecular Biology
• Computational Biophysics

Background:

• Fascin is a filamentous actin (F-actin) bundling protein crucial for cell surface structures like filopodia.
• Overexpression of fascin is linked to various cancers, and its mutations can affect F-actin binding and cancer progression.

Purpose of the Study:

• To investigate the functional impact of specific lysine residue mutations (K22, K41, K43, K241, K358, K399, K471) in fascin.
• To elucidate the role of these residues in fascin's structural dynamics and F-actin binding using molecular dynamics simulations.

Main Methods:

• Employed molecular dynamics (MD) simulations to analyze the effects of alanine mutations on seven key lysine residues in fascin.
• Utilized root mean square fluctuation (RMSF) analysis to assess local residue flexibility and thermal stability.
• Performed residue cross-correlation analysis to understand inter-residue dynamics and their impact on protein-wide flexibility.

Main Results:

• Mutations of strong-effect residues (K22, K41, K43, K358, K471) to alanine resulted in increased RMSF, indicating reduced flexibility and stability.
• Alanine mutations at these key sites enhanced residue correlations, extending local flexibility to the entire protein and influencing fascin's dynamics.
• Mutants K241A and K399A showed no significant changes in RMSF compared to wild-type fascin, consistent with their lack of functional impact.

Conclusions:

• Specific lysine residues are critical for maintaining fascin's structural integrity, flexibility, and thermal stability.
• Mutations in these residues can alter protein dynamics, affecting fascin's function in cellular processes.
• The study's findings align with experimental observations, validating the computational approach for understanding fascin mutations.