A Global Minimization Toolkit for Batch-Fitting and χ2 Cluster Analysis of CW-EPR Spectra

Effects of molecular flexibility and head group repulsion on aramid amphiphile self-assembly

“…[11][12][13] One such design motif is the aramid amphiphile (AA), which produces unusually stable self-assembled nanostructures by incorporating aromatic amide (aramid) domains into the molecular structure. [14][15][16] The prototypical AA is composed of a charged head group, a triaramid structural domain, and a short aliphatic tail (Fig. 1).…”

Dynamics in supramolecular nanomaterials

“…Electron paramagnetic resonance (EPR), enabled by site-directed spin labeling (SDSL), has received attention as a suitable technique that overcomes these limitations 61 . EPR spectroscopy is highly sensitive, requiring only small concentrations of spin label, and provides a precise measure of local dynamics via the rotational diffusion rate (typically on the order of 10 6 -10 9 Hz) of the radical nitroxyl spin label [62][63] .While the synthesis of stable spin-labeled molecules and technical data analysis previously precluded the implementation of EPR, recent developments in synthesis [64][65][66] and software [67][68] have made EPR accessible for investigating conformational dynamics. EPR has been used for measuring conformational dynamics on a self-assembled nanofibers composed of peptide amphiphiles (PAs).…”

Domain-Specific Phase Transitions in a Supramolecular Nanostructure

“…33 Spectra in this intermediate range can be fitted with a stochastic Liouville equation as implemented in the classic nonlinear least-squares stochastic Liouville (NLSL) program. 34 These fits may be carried out in batches via a chi-squared cluster analysis program (CSCA), 35 allowing us to determine local rotational diffusion rates to quantify conformational dynamics with sub-nanometer resolution. With this approach, differences in motional behavior can be identified between domains that may differ positionally by just a few bonds.…”