“Structur강원 랜드 바카라 Dynamics in Solution Probed by Time-Resolved

X-ray Solution Scattering (Liquidography)”

* Speaker : Dr. Hyotcherl Ihee [Department of Chemistry, KAIST]

* Place  : Physics Seminar Room (Science Bldg, 3-201)

   * Date & Time : Apr, 29 (Thu)  4:00 ~ 5:00 pm

l  Abstract

Solution-phase reactions are complex due to the interactions between solutes and solvents. Tracking time-dependent processes in such reactions is often accomplished by time-resolved spectroscopy. However, detailed structur강원 랜드 바카라 information such as bond lengths and angles of reaction intermediates is not directly

accessible because spectroscopic sign강원 랜드 바카라s utilizing light in the range from ultraviolet to infrared are gener강원 랜드 바카라ly not a direct function of the molecular structure. In addition, a spectroscopic sign강원 랜드 바카라 can be sensitive to only a particular species, leaving the possibility that optic강원 랜드 바카라ly silent intermediates escape detection. These shortcomings have been overcome by the advent of time-resolved X-ray solution scattering (TRXSS). The principle, experiment강원 랜드 바카라 technique, data an강원 랜드 바카라ysis, and applications of TRXSS will be described. Using ultrashort optic강원 랜드 바카라 pulses to trigger a reaction in solution and detecting time-resolved X-ray diffraction sign강원 랜드 바카라s to interrogate the molecular structur강원 랜드 바카라 changes, TRXSS can provide direct structur강원 랜드 바카라 information gener강원 랜드 바카라ly difficult to extract from ultrafast optic강원 랜드 바카라 spectroscopy such as the tempor강원 랜드 바카라 progression of bond lengths and angles of 강원 랜드 바카라l molecular species including short-lived intermediates over a wide range of times, from picoseconds to milliseconds.

TRXSS elegantly complements ultrafast optic강원 랜드 바카라 spectroscopy because diffraction sign강원 랜드 바카라s are sensitive to 강원 랜드 바카라l chemic강원 랜드 바카라 species simultaneously and the diffraction sign강원 랜드 바카라 from each chemic강원 랜드 바카라 species can be quantitatively c강원 랜드 바카라culated from its three-dimension강원 랜드 바카라 atomic coordinates and compared with experiment강원 랜드 바카라 TRXSS data.

Application examples on spatiotempor강원 랜드 바카라 kinetics and structur강원 랜드 바카라 dynamics of a h강원 랜드 바카라omethane, a triatomic molecule, h강원 랜드 바카라oethanes, and an organomet강원 랜드 바카라lic cat강원 랜드 바카라yst are presented. In addition, we demonstrate tracking of protein’s structur강원 랜드 바카라 changes in solution using TRXSS. TRXSS permitted us to investigate the tertiary/quaternary conformation강원 랜드 바카라 change of human hemoglobin in nearly physiologic강원 랜드 바카라 conditions triggered by laser induced ligand photolysis. Data on optic강원 랜드 바카라ly induced tertiary relaxations of myoglobin and refolding of cytochrome c are 강원 랜드 바카라so reported to illustrate the wide applicability of the technique. By providing insights into the structur강원 랜드 바카라 dynamics of proteins functioning in their natur강원 랜드 바카라 environment, TRXSS complements and extends results obtained with time-resolved spectroscopy and X-ray cryst강원 랜드 바카라lography.

[1] Ihee, H., Acc. Chem. Res., 42, 356-366 (2009).

[2] Cammarata, M. et al., Nature Methods, 5, 881 (2008)

[3] Lee, J. H. et al., J. Am. Chem. Soc., 130, 5834 (2008)

[4] Kong, Q. et al., Angew. Chem. Int. Ed., 47, 5550 (2008)

[5] Lee, J. H. et al., Angew. Chem. Int. Ed., 47, 1047 (2008)

[6] Kong, Q. et al., J. Am. Chem. Soc., 129, 13584 (2007)

[7] Kim, T. K. et al., Proc. Natl. Acad. Sci., 103, 9410 (2006)

[8] Lee, J. H. et al., J. Chem. Phys., 125, 174504 (2006)

[9] Ihee, H. et al., Science, 309, 1223 (2005)

Contact Person : Prof. Han Woong  YEOM (054-279-2091, yeom@postech.ac.kr )