Determining the stoichiometry of protein heterocomplexes in living cells with fluorescence fluctuation spectroscopy.

ABSTRACT: The brightness of fluorescence fluctuations provides information about protein interactions in the intercellular environment under equilibrium conditions. Here we demonstrate that the stoichiometry of a protein complex containing two proteins labeled with CFP and YFP can be determined by brightness analysis. The brightness profile, which characterizes the brightness as a function of the labeled protein coexpression ratio, together with brightness titration experiments, provides sufficient information to quantify the composition of a protein complex under stoichiometric binding conditions. The selective and simultaneous excitation of proteins labeled with CFP and YFP by choosing different excitation wavelengths is used to identify the composition of the protein complex. Interactions between

SUBMITTER: Chen Y 

PROVIDER: S-EPMC1805531 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature