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Reconstructing three-dimensional protein crystal intensities from sparse unoriented two-axis X-ray diffraction patterns

Cornell Affiliated Author(s)

Author

T.-Y. Lan
J.L. Wierman
M.W. Tate
H.T. Philipp
V. Elser
Sol Gruner

Abstract

Recently, there has been a growing interest in adapting serial microcrystallography (SMX) experiments to existing storage ring (SR) sources. For very small crystals, however, radiation damage occurs before sufficient numbers of photons are diffracted to determine the orientation of the crystal. The challenge is to merge data from a large number of such 'sparse' frames in order to measure the full reciprocal space intensity. To simulate sparse frames, a dataset was collected from a large lysozyme crystal illuminated by a dim X-ray source. The crystal was continuously rotated about two orthogonal axes to sample a subset of the rotation space. With the EMC algorithm [expand-maximize-compress; Loh & Elser (2009). Phys. Rev. E, 80, 026705], it is shown that the diffracted intensity of the crystal can still be reconstructed even without knowledge of the orientation of the crystal in any sparse frame. Moreover, parallel computation implementations were designed to considerably improve the time and memory scaling of the algorithm. The results show that EMC-based SMX experiments should be feasible at SR sources. © 2017.

Date Published

Journal

Journal of Applied Crystallography

Volume

50

Number of Pages

985-993,

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027014570&doi=10.1107%2fS1600576717006537&partnerID=40&md5=c66ae0667ef0edf07d40f8d1fddb2afc

DOI

10.1107/S1600576717006537

Group (Lab)

Sol M. Gruner Group
Veit Elser Group

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