Reorientation motions of N-acetyl-tryptophan-amide (NATA dipeptide) in aqueous solution and with co-solvents: Molecular dynamics vs hydrodynamic model

摘要: We present a study of peptide reorientational dynamics in solution analyzed from the perspective fluorescence anisotropy decay (FAD) experiments, and atomistic molecular (MD) continuum hydrodynamics modeling. Earlier, FAD measurements MD simulations model dipeptide N-acetyltryptophanamide (NATA) explicit water aqueous solutions urea, guanidinium chloride, proline co-solvents identified excellent agreement results with experimental data, indicating presence significant effects peptide–solvent interactions, overall tumbling could be well described by contributions individual conformers, represented dihedral-restrained MD. Here, we extend these studies analyzing dynamic inhomogeneity developing hydrodynamic (HM) conformer dynamics. The simulation data indicate markedly different microenvironments for four studied solutions, average reorientations being all systems, partly reflecting bulk viscosities. Additionally, also exhibited marked slowdown vicinity co-solvents, especially chloride proline. To gain further insight, applied HM to predict rotational correlation times tryptophan NATA conformers were very good structures, showing that provides realistic description diffusion rigid structures. Overall, our generated new microscopic insights into complex nature structure solvation shells systems containing denaturing stabilizing co-solvents.