Femtosecond X-ray liquidography captures the formation of chemical bond in the solution phase

Abstract

Femtosecond X-ray liquidography captures the formation of chemical bond in the solution phase

Hyotcherl Ihee Center for Nanomaterials and Chemical Reactions, IBS, Daejeon 305-701, South Korea Department of Chemistry, KAIST, Daejeon 305-701, South Korea, hyotcherl.ihee@kaist.ac.kr

The pump-probe X-ray diffraction and scattering techniques have now been fully established as a powerful method to investigate molecular structural dynamics [1-5]. We have employed the techniques to study structural dynamics and spatiotemporal kinetics of many molecular systems including diatomic molecules, haloalkanes, organometallic complexes and protein molecules over timescales from ps to milliseconds. X-ray crystallography, the major structural tool to determine 3D structures of proteins, can be extended to timeresolved X-ray crystallography with a laser-excitation and X-ray-probe scheme, but has been limited to a few model systems due to the stringent prerequisites such as highly-ordered and radiation-resistant single crystals. These problems can be overcome by applying time-resolved X-ray diffraction directly to protein solutions rather than protein single crystals. To emphasize that structural information can be obtained from the liquid phase, this time-resolved X-ray solution scattering technique is named time-resolved X-ray liquidography (TRXL) in analogy to time-resolved X-ray crystallography where the structural information of reaction intermediates is obtained from the crystalline phase. We will present our recent results including the achievement of femtosecond TRXL by using an X-ray free electron laser. [1] “Direct observation of bond formation in solution with femtosecond X-ray scattering”, K. H. Kim, J. G. Kim, S. Nozawa, T. Sato, K. Y. Oang, T. W. Kim, H. Ki, J. Jo, S. Park, C. Song, T. Sato, K. Ogawa, T. Togashi, K. Tono, M. Yabashi, T. Ishikawa, J. Kim, R. Ryoo, J. Kim, H. Ihee*, S. Adachi, Nature, 2015, 518, 385-389. [2] “Volume-conserving trans-cis isomerization pathways in photoactive yellow protein visualized by picosecond X-ray crystallography”, Y. O. Jung, J. H. Lee, J. Kim, M. Schmidt, K. Moffat, V. Srajer, H. Ihee*, Nat. Chem., 2013, 5, 212-220. [3] “Visualizing Solution-Phase Reaction Dynamics with Time-Resolved X-ray Liquidography”, H. Ihee*, Acc. Chem. Res., 2009, 42, 356-366 (Review Article). [4] “Tracking the structural dynamics of proteins in solution using time-resolved wide-angle X-ray scattering”, M. Cammarata*, M. Levantino, F. Schotte, P. A. Anfinrud, F. Ewald, J. Choi, A. Cupane, M. Wulff, H. Ihee*, Nature Methods, 2008, 5, 881-887. [5] “Ultrafast X-ray diffraction of transient molecular structures in solution”, H. Ihee*, M. Lorenc, T. K. Kim, Q. Y. Kong, M. Cammarata, J. H. Lee, S. Bratos, M. Wulff, Science, 2005, 309, 1223-1227.