- Categories:Structural Biology
- Time of issue:2020-09-08 14:30:49
What is MicroED?
Microcrystal electron diffraction (MicroED) is a powerful technique used to resolve high resolution structure of small molecule compound. A microcrystal refers to a crystal whose dimension is between 100nm to 400 nm, which is too small to be administered with the method of X-ray crystallography. A microcrystals can be radiated by electron beam and give diffraction patterns while goniometer of microscope rotates continuously. Then, the diffraction dataset can be processed by conventional crystallographic programs for a rapid atomic resolution (usually better than 1A) structure determination.
Why do you need MicroED Services?
In many cases, a chemical compound tends to form a crystal with a dimension of hundres of nanometers, which excludes the application of X-ray technology for the structure determination. Even though trying different crystallization condition might increases a chance of getting a larger crystal, but this trial usually requires much more costly compounds and the result is unpredictable. However, such a small crystal is the perfect fit for the microED technique.
MicroED can answer your following questions:
What is the structure of my chemical compound?
What is the crystal form of my drug?
What is the minor crystalline component of CMC?
Why choose Biortus for MicroED?
Biortus has its own TEM in house, sufficient machine time and fast result feedback (usually in a couple of days) can be guaranteed. As one of the first microED service providers in the world, Biortus has delivered many small molecule structures at atomic resolution.
Our MicroED Workflow: From Sample to Structure
· Sample preparation:
We prefer the sample is in the form of powder, and it is essential that the powder contains microcrystals, which can be confirmed with powder X-ray. Minimal amount of powder is put onto a TEM grid, frozen by liquid nitrogen, and the grid will be put into the electron microscope for imaging.
· Data acquisition:
A low-mag view of the grid may show hundreds of crystals, and the most time-consuming work is to identify those perfect crystals which give high-resolution diffractions. The diffraction patterns will be acquired automatically on our in-house TF20 microscope.
· Data processing:
The procedure of data processing is pretty similar to that of traditional X-ray crystallography.
· Structure determination:
The phasing problem can be solved by direct method, dual-space methods and/or molecular replacement methods. Initial models are constructed and further refined, during which all atoms will be allocated and assessed for consistency according to the proposed 2D structure.