Multidomain structure and correlated dynamics determined by self-consistent FRET networks.

ABSTRACT

We present an approach that enables us to simultaneously access structure and dynamics of a multidomain protein in solution. Dynamic domain arrangements are experimentally determined by combining self-consistent networks of distance distributions with known domain structures. Local structural dynamics are correlated with the global arrangements by analyzing networks of time-resolved single-molecule fluorescence parameters. The strength of this hybrid approach is shown by an application to the flexible multidomain protein Hsp90. The average solution structure of Hsp90's closed state resembles the known X-ray crystal structure with Angstrom precision. The open state is represented by an ensemble of conformations with interdomain fluctuations of up to 25 Å. The data reveal a state-specific suppression of the submillisecond fluctuations by dynamic protein-protein interaction. Finally, the method enables localization and functional characterization of dynamic elements and domain interfaces.