PT  - JOURNAL ARTICLE
AU  - Zhu, Lan
AU  - Bu, Guanhong
AU  - Jing, Liang
AU  - Shi, Dan
AU  - Gonen, Tamir
AU  - Liu, Wei
AU  - Nannenga, Brent L.
TI  - Structure determination from lipidic cubic phase embedded microcrystals by MicroED
AID  - 10.1101/724575
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 724575
4099  - http://biorxiv.org/content/early/2019/08/04/724575.short
4100  - http://biorxiv.org/content/early/2019/08/04/724575.full
AB  - The lipidic cubic phase (LCP) technique has proved to facilitate the growth of high-quality crystals that are otherwise difficult to grow by other methods. Because crystals grown in LCP can be limited in size, improved techniques for structure determination from these small crystals are important. Microcrystal electron diffraction (MicroED) is a technique that uses a cryo-TEM to collect electron diffraction data and determine high-resolution structures from very thin micro and nanocrystals. In this work, we have used modified LCP and MicroED protocols to analyze crystals embedded in LCP. Proteinase K in LCP was used as a model system, and several LCP sample preparation strategies were tested. Among these, treatment with 2-Methyl-2,4-pentanediol (MPD) and lipase were both able to reduce the viscosity of the LCP and produce quality cryo-EM grids with well-diffracting crystals. These results set the stage for the use of MicroED to analyze other microcrystalline samples grown in LCP.