RT Journal Article SR Electronic T1 Analysis of global and site-specific radiation damage in cryo-EM JF bioRxiv FD Cold Spring Harbor Laboratory SP 258178 DO 10.1101/258178 A1 Hattne, Johan A1 Shi, Dan A1 Glynn, Calina A1 Zee, Chih-Te A1 Gallagher-Jones, Marcus A1 Martynowycz, Michael W. A1 Rodriguez, Jose A. A1 Gonen, Tamir YR 2018 UL http://biorxiv.org/content/early/2018/02/01/258178.abstract AB Micro-crystal electron diffraction (MicroED) is an emerging method in cryo-EM for structure determination using nanocrystals. It has been used to solve structures of a diverse set of biomolecules and materials, in some cases to sub-atomic resolution. However, little is known about the damaging effects of the electron beam on samples during such measurements. We assess global and site-specific damage from electron radiation on nanocrystals of proteinase K and of a prion hepta-peptide and find that the dynamics of electron-induced damage follow well-established trends observed in X-ray crystallography. Metal ions are perturbed, disulfide bonds are broken, and acidic side chains are decarboxylated while the diffracted intensities decay exponentially with increasing exposure. A better understanding of radiation damage in MicroED improves our assessment and processing of all types of cryo-EM data.