W0424

Advances in Time-Resolved Macromolecular Crystallography. Keith Moffat, Dept. of Biochemistry & Molecular Biology, and Inst. for Biophysical Dynamics, Univ. of Chicago, Chicago, IL 60637.

There are three major frontiers in time-resolved macromolecular crystallography: 1) the application of today’s successful techniques, with a time resolution of a few hundred picoseconds limited by the synchrotron X-ray pulse length, to novel biological systems; 2) the development and application of new mathematical tools such as singular value decomposition (SVD) to the determination of mechanism, and hence to the identification of the number and time-independent, structural nature of the short-lived intermediates that populate the mechanism; and 3) the development of new, linear-accelerator-based X-ray sources such as the Sub-Picosecond Photon Source and the Linac Coherent Light Source at Stanford Synchrotron Radiation Laboratory that are intended to offer brilliant X-ray pulses whose duration is around 100 femtoseconds, roughly three orders of magnitude shorter than those available from synchrotron sources. The first and second will be illustrated by recent results on the blue light photoreceptors, photoactive yellow protein from bacteria and the LOV2 domain of phototropin from plants. Comparisons will be drawn with results from “conventional” cryocrystallography.