Monochromatic multicomponent fluorescence sedimentation velocity for the study of high-affinity protein interactions

Autor: Huaying Zhao, Yan Fu, Carla Glasser, Eric J Andrade Alba, Mark L Mayer, George Patterson, Peter Schuck
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: eLife, Vol 5 (2016)
Druh dokumentu: article
ISSN: 2050-084X
DOI: 10.7554/eLife.17812
Popis: The dynamic assembly of multi-protein complexes underlies fundamental processes in cell biology. A mechanistic understanding of assemblies requires accurate measurement of their stoichiometry, affinity and cooperativity, and frequently consideration of multiple co-existing complexes. Sedimentation velocity analytical ultracentrifugation equipped with fluorescence detection (FDS-SV) allows the characterization of protein complexes free in solution with high size resolution, at concentrations in the nanomolar and picomolar range. Here, we extend the capabilities of FDS-SV with a single excitation wavelength from single-component to multi-component detection using photoswitchable fluorescent proteins (psFPs). We exploit their characteristic quantum yield of photo-switching to imprint spatio-temporal modulations onto the sedimentation signal that reveal different psFP-tagged protein components in the mixture. This novel approach facilitates studies of heterogeneous multi-protein complexes at orders of magnitude lower concentrations and for higher-affinity systems than previously possible. Using this technique we studied high-affinity interactions between the amino-terminal domains of GluA2 and GluA3 AMPA receptors.
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