Browsing by Author "Anfinrud, Philip A."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Fixed target matrix for femtosecond time-resolved andᅠin situᅠserial micro-crystallography(AIP Publishing LLC, 2015) Mueller, C.; Marx, A.; Epp, S.W.; Zhong, Y.; Kuo, A.; Balo, A.R.; Soman, J.; Schotte, F.; Lemke, H.T.; Owen, R.L.; Pai, E.F.; Pearson, A.R.; Olson, J.S.; Anfinrud, Philip A.; Ernst, O.P.; Miller, R.J.DwayneWe present a crystallography chip enablingᅠin situᅠroom temperature crystallography at microfocus synchrotron beamlines andᅠX-rayᅠfree-electron laser (X-FEL) sources. Compared to otherᅠin situapproaches, we observe extremely low background and highᅠdiffractionᅠdata quality. The chip design is robust and allows fast and efficient loading of thousands of small crystals. The ability to load a large number ofᅠproteinᅠcrystals, at room temperature and with high efficiency, into prescribed positions enables high throughput automated serial crystallography with microfocus synchrotron beamlines. In addition, we demonstrate the application of this chip for femtosecond time-resolved serial crystallography at the Linac Coherent Light Source (LCLS, Menlo Park, California, USA). The chip concept enables multiple images to be acquired from each crystal, allowing differential detection of changes inᅠdiffractionᅠintensities in order to obtain high signal-to-noise and fully exploit the time resolution capabilities of XFELs.Item Real-time tracking of CO migration and binding in the ? and ? subunits of human hemoglobin via 150-ps time-resolved Laue crystallography(Elsevier, 2013) Schotte, Friedrich; Cho, Hyun Sun; Soman, Jayashree; Wulff, Michael; Olson, John S.; Anfinrud, Philip A.; W.M. Keck Center for Computational BiologyWe have developed the method of picosecond Laue crystallography and used this capability to probe ligand dynamics in tetrameric R-state hemoglobin (Hb). Time-resolved, 2 Å-resolution electron density maps of photolyzed HbCO reveal the time-dependent population of CO in the binding (A) and primary docking (B) sites of both α and β subunits from 100 ps to 10 μs. The proximity of the B site in the β subunit is about 0.25 Å closer to its A binding site, and its kBA rebinding rate (∼300 μs−1) is six times faster, suggesting distal control of the rebinding dynamics. Geminate rebinding in the β subunit exhibits both prompt and delayed geminate phases. We developed a microscopic model to quantitatively explain the observed kinetics, with three states for the α subunit and four states for the β subunit. This model provides a consistent framework for interpreting rebinding kinetics reported in prior studies of both HbCO and HbO2.