In many cases, the powerful tools of structural biology are insufficient to retrieve the structures of proteins in specific conformational states serving specific stages in the overall function.

Single-molecule fluorescence spectroscopy experiments facilitate sorting different bio-molecular species according to their inter-atomic distances, rotational freedom, binding stocihiometry, and many other parameters that influence fluorescence. Using this, we uncover unique conformational states of protein systems that haven't yet been characterized structurally. We then combine the experimental data with structural modeling to retrieve 3D structure models of these conformational states.