Insulin hexamer dissociation dynamics revealed by photoinduced T-jumps and time-resolved X-ray solution scattering

Abstract

The structural dynamics of insulin hexamer dissociation were studied by the photoinduced temperature jump technique and monitored by time-resolved X-ray scattering. The process of hexamer dissociation was found to involve several transient intermediates, including an expanded hexamer and an unstable tetramer. Our findings provide insights into the mechanisms of protien-protein association.

Temperature-jump solution X-ray scattering reveals distinct motions in a dynamic enzyme

“…[13][14][15][16][17][18] ). Unfortunately, the number of proteins that undergo specific photochemistry as part of their functional cycle is small, and there is a fundamental need to develop generalized methods that can be used to synchronously excite conformational transitions in any protein molecule and expand the utility of time-resolved structural experiments [19][20][21][22][23][24][25][26][27] .…”

“…That study explored only a single pump-probe time delay, which allowed them to observe laser-induced structural changes but precluded kinetic analysis. Within the last two years, the laser T-jump method has been paired with X-ray solution scattering to explore the oligomerization of insulin in non-physiological conditions 25,26 and hemoglobin 27 . The results and analysis we present here expand the role of the T-jump method in structural biology, by demonstrating that T-jump X-ray scattering experiments can be used as a general method to explore the functional, internal dynamics of proteins in solution.…”

Determining the charge distribution and the direction of bond cleavage with femtosecond anisotropic x-ray liquidography

“…or understanding the reaction mechanism and reaction pathway of a chemical reaction, it is critical to track the change of the energy levels and three-dimensional structure in the reaction. Time-resolved spectroscopic techniques [1][2][3][4][5][6][7][8][9] provide direct information on the energy flow based on the sensitivity to energy states, and time-resolved diffraction [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] directly tracks the time-dependent structural change of a molecule based on the structural sensitivity. The charge distribution of a molecule or the flow of charge during a reaction plays a role as important as energy and structure, especially in reactions involving chargetransfer processes such as reactions in photoelectric and electrochemical devices 26,27 .…”

X-ray snapshots reveal conformational influence on active site ligation during metalloprotein folding

“…The scattering difference signals free of the buffer heating contribution were obtained by using standard procedures as in previous works (see ESI for details †). [34][35][36][37] The resulting difference signals containing protein only contributions at selected time delays are shown in Fig. 2b.…”