Eur. Phys. J. E (2013) 36: 109
https://doi.org/10.1140/epje/i2013-13109-9

Regular Article

X-ray scattering experiments with high-flux X-ray source coupled rapid mixing microchannel device and their potential for high-flux neutron scattering investigations

¹ Structural Dynamics of (Bio)chemical Systems, MPI-BPC, Am Fassberg 11, 37077, Goettingen, Germany
² Biological Micro- and Nanotechnology, MPI-BPC, Am Fassberg 11, 37077, Goettingen, Germany
³ Center of Advanced European Studies and Research (caesar), Micro Systems Technology (MST), 53175, Bonn, Germany
⁴ NMR-based Structural Biology, MPI-BPC, Am Fassberg 11, 37077, Goettingen, Germany
⁵ Paul Scherrer Institut, 5232, Villigen, Switzerland
⁶ Structural Dynamics of (Bio)chemical Systems at the Photon Research Division, DESY, Notkesstrasse 85, 22607, Hamburg, Germany

^* e-mail: tburg@mpibpc.mpg.de
^** e-mail: stecher@gwdg.de
^*** e-mail: simone.techert@desy.de

Received: 29 November 2012
Revised: 13 December 2012
Accepted: 26 July 2013
Published online: 27 September 2013

Abstract

Small-angle X-ray scattering provides global, shape-sensitive structural information about macromolecules in solution. Its extension to time dimension in the form of time-resolved SAXS investigations and combination with other time-resolved biophysical methods contributes immensely to the study of protein dynamics. TR-SAXS can also provide unique information about the global structures of transient intermediates during protein dynamics. An experimental set-up with low protein consumption is essential for an extensive use of TR-SAXS experiments on protein dynamics. In this direction, a newly developed 20-microchannel microfluidic continuous-flow mixer was combined with SAXS. With this set-up, we demonstrate ubiquitin unfolding dynamics after rapid mixing with the chaotropic agent Guanidinium-HCl within milliseconds using only ∼ 40 nanoliters of the protein sample per scattering image. It is suggested that, in the future, this new TR-SAXS platform will help to increase the use of time-resolved small-angle X-ray scattering, wide-angle X-ray scattering and neutron scattering experiments for studying protein dynamics in the early millisecond regime. The potential research field for this set-up includes protein folding, protein misfolding, aggregation in amyloidogenic diseases, function of intrinsically disordered proteins and various protein-ligand interactions.