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Published November 28, 2018 | Supplemental Material + Submitted + Published
Journal Article Open

The CryoEM Method MicroED as a Powerful Tool for Small Molecule Structure Determination


In the many scientific endeavors that are driven by organic chemistry, unambiguous identification of small molecules is of paramount importance. Over the past 50 years, NMR and other powerful spectroscopic techniques have been developed to address this challenge. While almost all of these techniques rely on inference of connectivity, the unambiguous determination of a small molecule's structure requires X-ray and/or neutron diffraction studies. In practice, however, X-ray crystallography is rarely applied in routine organic chemistry due to intrinsic limitations of both the analytes and the technique. Here we report the use of the electron cryo-microscopy (cryoEM) method microcrystal electron diffraction (MicroED) to provide routine and unambiguous structural determination of small organic molecules. From simple powders, with minimal sample preparation, we could collect high-quality MicroED data from nanocrystals (∼100 nm, ∼10^(–15) g) resulting in atomic resolution (<1 Å) crystal structures in minutes.

Additional Information

© 2018 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Received: October 17, 2018; Published: November 2, 2018. Accession Codes: Data and materials availability: MicroED density maps have been deposited to the PDB (thiostrepton, 6MXF), EMDB (EMD-9282, EMD-9284, EMD-9285, EMD-9286, EMD-9287, EMD-9288, EMD-9289, EMD-9290, EMD-9291, EMD-9292), and CCDC (1876036, 1876037, 1876038, 1876039, 1876040, 1876041, 1876042, 1876043, 1876044, 1876045). Author Contributions: C.G.J. and M.W.M. contributed equally. C.G.J. performed experiments, developed the sample preparation techniques, refined structural data, prepared figures, and assisted with manuscript preparation. M.W.M performed experiments, developed the sample preparation techniques, collected data, refined structural data, prepared figures, and assisted with manuscript preparation. T.F. performed experiments. J.H. wrote the software for image conversion, participated in data analysis, refinement, and structure determination. J.A.R. performed experiments, developed the sample preparation techniques, and assisted with manuscript preparation. B.M.S. conceived of the project, designed experiments, and assisted with manuscript preparation. H.M.N. conceived of the project, designed experiments, performed experiments, developed the sample preparation techniques, and assisted with manuscript and figure preparation. T.G. performed experiments, collected data, developed the sample prep techniques, developed microscope data collection parameters, provided the microscope and expertise, and assisted in manuscript and figure preparation. C.G.J. would like to acknowledge the National Science Foundation for a predoctoral fellowship (DGE-1650604). B.M.S. acknowledges the NIH-NIGMS for generous funding (R01GM080269). J.A.R. is supported by DOE Grant DE-FC02-02ER63421, NIH-NIGMS Grant R35GM128867, and as a Beckman Young Investigator, a Searle Scholar, and a Pew Scholar. H.M.N. thanks The Packard Foundation, The Sloan Foundation, Pew Charitable Trusts, and the NIH-NIGMS (R35 GM128936) for generous funding. The Gonen laboratory is supported by funds from the Howard Hughes Medical Institute. The authors declare no competing financial interest. We thank Profesor Doug Rees (Caltech), Professor Bil Clemons (Caltech), and Dr. Michael Sawaya (UCLA) for useful discussions. We thank Byungkuk Yoo and Michael Takase (Caltech) for technical assistance with data analysis. We thank Beau Pritchett and Hendrik Klare for providing synthetic samples.

Attached Files

Published - acscentsci.8b00760.pdf

Submitted - MicroED_Combined.pdf

Supplemental Material - oc8b00760_si_001.avi

Supplemental Material - oc8b00760_si_002.pdf


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