Experimental techniques employed are analytical ultracentrifugation, static and dynamic light scattering, isothermal titration microcalorimetry, differential scanning calorimetry, circular dichroism spectroscopy, fluorescence polarization, and surface plasmon resonance biosensing. Specifically, in collaboration with Dr. Mark Mayer, we have applied our new sedimentation velocity methodology for high-affinity interactions to the study of glutamate receptor subunit interactions, in particular GluA2. This system also provided the opportunity for us to embark on orthogonal experiments using sedimentation equilibrium and steady-state fluorescence anisotropy, validating our appraoch. Similar sedimentation methodology was also used to the study of the high-affinity interaction of Swi6 oligomerization and histone binding, jointly with Dr. Geeta Narlikar. In a different, longstanding collaboration with Dr. Lawrence Samelson's laboratory on the assembly of adaptor proteins to multi-protein signaling complexes, we have been able to elucidate the stoichiometry of binding between ADAP and SLP76 peptides, using a combination of calorimetric (global analysis) and multi-signal sedimentation velocity approaches. This provided us with new insights to the limitations and opportunities of both techniques. We have also continued to develop and apply computational methodology for the study of amyloid fibrils, and the evolution of their size-distribution. This led to a new collaboration with the Herr laboratory on the formation of Aap amyloids in biofilms, and the continuation of our work with the Howlett laboratory on the properties of apolipoprotein C-II amyloid fibrils. Finally, we have continued applications of our computational prediction tool of polypeptide refractive index increments, which led to the recognition of the functional role of gamma crystallin molecular refractive index, and the role of intracellular crowding in fiber cells as a driving force of crystallin evolution. In collaboration with Dr. Graeme Wistow, we have embarked on experimental studies of biophysical properties of gamma crystallins from different species that are interesting in the evolutionary context.
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