CHARMM force field generation for a cationic thiophene oligomer with ffTK

Area of Science:

• Computational chemistry
• Biophysical chemistry
• Materials science

Background:

• Cationic polythiophenes (CPTs) exhibit altered spectroscopic properties in the presence of biologically relevant anions like ATP and AMP.
• Understanding these interactions is crucial for developing novel biosensing platforms.

Purpose of the Study:

• To generate CHARMM-compatible force field parameters for a specific cationic oligothiophene.
• To investigate the structural dynamics of the oligothiophene in complex with adenosine nucleotides (AMP and ATP) using molecular dynamics (MD) simulations.
• To validate the generated force field parameters through comparison with experimental UV-VIS spectroscopy data.

Main Methods:

• Generation of CHARMM force field parameters using the force field toolkit (ffTK).
• Molecular dynamics (MD) simulations of a 20-mer oligothiophene and its complexes with AMP and ATP.
• Analysis of simulation results to determine the effect of phosphate number on oligothiophene backbone structure.
• UV-VIS spectroscopic calculations for representative conformers to validate the force field.

Main Results:

• CHARMM force field parameters were successfully generated for the N,N,N-trimethyl-3-((4-methylthiophen-3-yl)oxy)propan-1-aminium oligomer.
• MD simulations provided insights into how the number of phosphates in adenosine nucleotides influences the oligothiophene backbone structure.
• UV-VIS calculations correlated well with experimental data, confirming the accuracy of the generated force field.

Conclusions:

• The developed CHARMM force field parameters enable accurate simulation of cationic oligothiophenes interacting with biological molecules.
• This work lays the foundation for advanced biosensor development by elucidating the structural basis of CPT-nucleotide interactions.
• The validated force field can be used to explore further complex formation and design novel biosensing strategies.