Conformational Ensembles from Experimental Data and Computer Simulations

Conformational Ensembles from Experimental Data and Computer Simulations

Poster Abstracts

41-POS Board 1 Dynamic Structure of the Protein Hsp90 Solved by a Hybrid Approach Based on Single

Molecule FRET Thorsten Hugel . n/a, Freiburg, Germany.

Most molecular machines alternate dynamically between multiple conformations. Common techniques are not ideal to study such conformational dynamics on relevant time scales from micro-seconds to several seconds. Here we present a hybrid approach based on single molecule FRET combined with X-ray crystal structure data and simulations. This approach enables us to simultaneously access structure and dynamics of a multi-domain protein in solution [1]. We applied this method to solve the dynamic structures of the heat shock protein Hsp90 dimer in solution. The previously unknown open state of yeast Hsp90 is represented by an ensemble of conformations with inter-domain fluctuations of up to 25 Å. In addition, we show how multicolor single molecule FRET allows us to identify microscopic states in transient complexes. Conformational dynamics and nucleotide binding are simultaneously detected for Hsp90. Their correlation is quantified using 3D ensemble hidden Markov analysis, in and out of equilibrium [2,3]. [1] B. Hellenkamp, P. Wortmann, F. Kandzia, M. Zacharias, T. Hugel. Multidomain structure and correlated dynamics determined by self-consistent FRET networks. Nat Meth;14(2):174-180 (2017). [2] S. Schmid, M. Götz and T. Hugel. Single-Molecule Analysis beyond Dwell Times: Demonstration and Assessment in and out of Equilibrium. Biophys J. 111:1375-1384 (2016) [3] M. Götz, P. Wortmann, S. Schmid and T. Hugel. A multi-color single molecule FRET approach to study protein dynamics and interactions simultaneously. Method Enzymol 581, 487- 516 (2016)

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