@article {46380, title = {Data Exploration Toolkit for serial diffraction experiments.}, journal = {Acta Crystallographica Section D: Biological Crystallography}, volume = {71}, year = {2015}, month = {2015 Feb}, pages = {352-6}, abstract = {

Ultrafast diffraction at X-ray free-electron lasers (XFELs) has the potential to yield new insights into important biological systems that produce radiation-sensitive crystals. An unavoidable feature of the {\textquoteleft}diffraction before destruction{\textquoteright} nature of these experiments is that images are obtained from many distinct crystals and/or different regions of the same crystal. Combined with other sources of XFEL shot-to-shot variation, this introduces significant heterogeneity into the diffraction data, complicating processing and interpretation. To enable researchers to get the most from their collected data, a toolkit is presented that provides insights into the quality of, and the variation present in, serial crystallography data sets. These tools operate on the unmerged, partial intensity integration results from many individual crystals, and can be used on two levels: firstly to guide the experimental strategy during data collection, and secondly to help users make informed choices during data processing.

}, issn = {1399-0047}, doi = {10.1107/S1399004714025875}, author = {Zeldin, Oliver B and Brewster, Aaron S and Hattne, Johan and Uervirojnangkoorn, Monarin and Lyubimov, Artem Y and Zhou, Qiangjun and Zhao, Minglei and Weis, William I and Sauter, Nicholas K and Brunger, Axel T} } @article {46526, title = {Enabling X-ray free electron laser crystallography for challenging biological systems from a limited number of crystals.}, journal = {eLife}, volume = {4}, year = {2015}, month = {2015 Mar 17}, abstract = {

There is considerable potential for X-ray free electron lasers (XFELs) to enable determination of macromolecular crystal structures that are difficult to solve using current synchrotron sources. Prior XFEL studies often involved the collection of thousands to millions of diffraction images, in part due to limitations of data processing methods. We implemented a data processing system based on classical post-refinement techniques, adapted to specific properties of XFEL diffraction data. When applied to XFEL data from three different proteins collected using various sample delivery systems and XFEL beam parameters, our method improved the quality of the diffraction data as well as the resulting refined atomic models and electron density maps. Moreover, the number of observations for a reflection necessary to assemble an accurate data set could be reduced to a few observations. These developments will help expand the applicability of XFEL crystallography to challenging biological systems, including cases where sample is limited.

}, issn = {2050-084X}, doi = {10.7554/eLife.05421}, author = {Uervirojnangkoorn, Monarin and Zeldin, Oliver B and Lyubimov, Artem Y and Hattne, Johan and Brewster, Aaron S and Sauter, Nicholas K and Brunger, Axel T and Weis, William I} } @article {47031, title = {Structure of the toxic core of α-synuclein from invisible crystals.}, journal = {Nature}, volume = {525}, year = {2015}, month = {2015 Sep 9}, pages = {486-90}, abstract = {

The protein α-synuclein is the main component of Lewy bodies, the neuron-associated aggregates seen in Parkinson disease and other neurodegenerative pathologies. An 11-residue segment, which we term NACore, appears to be responsible for amyloid formation and cytotoxicity of human α-synuclein. Here we describe crystals of NACore that have dimensions smaller than the wavelength of visible light and thus are invisible by optical microscopy. As the crystals are thousands of times too small for structure determination by synchrotron X-ray diffraction, we use micro-electron diffraction to determine the structure at atomic resolution. The 1.4 {\r A} resolution structure demonstrates that this method can determine previously unknown protein structures and here yields, to our knowledge, the highest resolution achieved by any cryo-electron microscopy method to date. The structure exhibits protofibrils built of pairs of face-to-face β-sheets. X-ray fibre diffraction patterns show the similarity of NACore to toxic fibrils of full-length α-synuclein. The NACore structure, together with that of a second segment, inspires a model for most of the ordered portion of the toxic, full-length α-synuclein fibril, presenting opportunities for the design of inhibitors of α-synuclein fibrils.

}, issn = {1476-4687}, doi = {10.1038/nature15368}, author = {Rodriguez, Jose A and Ivanova, Magdalena I and Sawaya, Michael R and Cascio, Duilio and Reyes, Francis E and Shi, Dan and Sangwan, Smriti and Guenther, Elizabeth L and Johnson, Lisa M and Zhang, Meng and Jiang, Lin and Arbing, Mark A and Nannenga, Brent L and Hattne, Johan and Whitelegge, Julian and Brewster, Aaron S and Messerschmidt, Marc and Boutet, S{\'e}bastien and Sauter, Nicholas K and Gonen, Tamir and Eisenberg, David S} }