Paper
19 October 2012 Phase retrieval in nanocrystallography
Joe P. J. Chen, John C. H. Spence, Rick P. Millane
Author Affiliations +
Abstract
Protein X-ray crystallography is a method for determining the three-dimensional structures of large biological molecules by analysing the amplitudes of X-rays scattered from a crystalline specimen of the molecule under study. Conventional structure determination in protein crystallography requires chemical modification to the sample and collection of additional data in order to solve the corresponding phase problem. There is an urgent need for a direct (digital) low-resolution phasing method that does not require modified specimens. Whereas diffraction from large crystals corresponds to samples (so-called Bragg samples) of the amplitude of the Fourier transform of the scattering density, the diffraction from very small crystals allows measurement of the diffraction amplitude between the Bragg samples. Although highly attenuated, these additional measurements offer the possibility of iterative phase retrieval without the use of ancillary experimental data. In this study we examine the noise characteristics of small-crystal diffraction and propose a data selection strategy to improve the quality of reconstructions using iterative phase retrieval algorithms. Simulation results verify that a higher noise level can be tolerated by using such a data selection strategy.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Joe P. J. Chen, John C. H. Spence, and Rick P. Millane "Phase retrieval in nanocrystallography", Proc. SPIE 8500, Image Reconstruction from Incomplete Data VII, 85000I (19 October 2012); https://doi.org/10.1117/12.930930
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KEYWORDS
Crystals

Nanocrystals

Signal to noise ratio

X-rays

Phase retrieval

Molecules

Sensors

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