Molecular Dynamics Simulations of Dialkyl Carbocyanine Dyes in a DPPC Bilayer: Atomistic Insights Into Single Molecule Fluorescence

Our group uses di-alkyl carbocyanine dyes to detect force-induced membrane perturbation in mechanotransduction studies (Butler et al 2000). These dyes are also used extensively in single molecule spectroscopic techniques to infer dynamics of native membrane lipids. However, the precise distribution and orientation of the dye in a bilayer and how well the dye dynamics mimic native lipid dynamics are not known. Thus we present the results of a 40 nanosecond molecular dynamics simulation of a fully hydrated bilayer containing 0, 2, or 4 molecules of 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI-C18) and 128 molecules of dipalmitoylphosphatidyl choline (DPPC).