POLYCAPILLARY X-RAY OPTICS FOR MACROMOLECULAR CRYSTALLOGRAPHY. S. M. Owens^*, J. B. Ullrich^#, I. Yu. Ponomarev^#, Q.-F. Xiao^#, D. Carter⁺, R. C. Sisk⁺, and W. M. Gibson^{*. *}Center for X-ray Optics, University at Albany, Albany, NY 12222; ^#X-Ray Optical Systems, 90 Fuller Rd., Albany, NY 12205; ⁺Laboratory for Structural Biology, NASA Marshall Space Flight Center, Huntsville, AL 35812.

Polycapillary x-ray optics have shown great potential in macromolecular x-ray crystallography. Incorporation of polycapillary x-ray optics into existing x-ray sources yields significant increases in beam intensity compared to simple collimation. The optic used in this work collects x-rays from the source over a large solid angle (6deg. capture angle) and redirects them into a quasi-parallel beam (<0.2deg. divergence) of 5 mm diameter. Using this optic coupled to a modified RU200 rotating anode source, we recently produced a gain in flux through a 0.3 mm collimator of more than an order of magnitude over a comparable graphite monochromated source. Using large, microgravity grown lysozyme crystals as a "standard", we collected full data sets with and without Ni filtering of the primary beam (the high energy rejection of the optics allows measurements to be done without further filtering). Without filtering, a complete data set, to a minimum of 1.54 Å resolution, was obtained within 13.4 hours with a final Rmerg of 7.29 % (based on all observations). The data were collected with a Siemens Multiwire detector, read by FRAMBO and analyzed using SAINT. We have made similar measurements with a prototype optic which produces a weakly convergent beam (< 1deg. convergence), and further increases the flux gain to more than 100. Full data sets using this optic have also been collected. Details of the data reduction and analyses, as well as applications to structure determinations, will be presented.