A brand new methodology revealed in Nature Methods removes a lot of the guesswork and time-consuming optimization from pattern preparation for cryo-electron microscopy and tomography (cryo-EM/ET). To picture macromolecules beneath a microscope, they must be suspended in a thick water resolution, much like the light-transmitting vitreous layer that fills most of our eyeballs between the lens and the retina. Specimens are then unfold out on a grid and flash-frozen right into a glassy layer of ice. Pattern thickness relies upon closely on the answer, grid composition, and freezing (vitrification) course of, and researchers should optimize every parameter to acquire high-quality pictures. The newly described platform, known as EasyGrid, automates pattern vitrification and grid optimization, decreasing the fee and time required to conduct cryo-EM/ET research.
The EasyGrid platform reduces human error and energy by introducing a customized grid rack, automated grid dealing with module, plasma remedy module, and automatic pattern pipette to organize the grid and dispense the macromolecular pattern. A pressure-wave-based pattern spreading system mixed with a vitrification and storage module fastidiously management the pattern thickness and freezing course of. The platform can also be geared up with the EasyGrid Management module, which maps ice thickness throughout the grid at a number of magnification ranges to make sure grid usability for single particle evaluation (SPA), the strategy used to find out 3D macromolecular constructions.
To show the brand new EasyGrid workflow, researchers carried out SPA for well-characterized benchmark samples in addition to much less tractable samples from micro organism and fungi. EasyGrid yielded high-quality cryo-EM pictures, in addition to new structural insights for samples such because the bacterial KR2 rhodopsin complicated, whose construction had not beforehand been decided by cryo-EM.
Crystalline ice formation is a significant hindrance to resolving macromolecular constructions with cryo-EM/ET. Jet vitrification solves this situation by cooling the pattern quickly and evenly. The examine authors confirmed that by using jet vitrification, EasyGrid enabled the acquisition of cryoEM pictures with out ice artifacts in 77% of HeLa cell sections, in comparison with solely 11% of cell sections with out ice formation when a plunge-freezing methodology was used as an alternative.
Future developments in EasyGrid expertise will embrace greater magnification ranges to enhance and pinpoint ice thickness measurements, the addition of a fluorescence microscope for mobile samples, and modular on-grid pattern mixing procedures to seize biomolecular processes in actual time with stop-motion cryo-EM. The authors summarized EasyGrid’s benefits for cryo-EM researchers: “EasyGrid enhances cryo-EM/ET facility capabilities by streamlining pattern screening, enabling jet vitrification of cells, and automating the optimization of each mobile and biochemical samples.”
Supply: Nature Methods
