TECHNOTES
Maximizing Productivity in Your Crystallography Lab

1. Replace your existing loops with MicroMounts™, MicroLoops™, MicroGrippers™ and MicroMeshes™. Because of their rigidity, scoop-like action and reproducible dimensions, new users can master sample mounting much more quickly. Experienced users can successfully mount a much larger fraction of their crystals.

Sample retrieval and mounting tools are cheap compared with the cost of producing and crystallizing protein. And you can buy a lot of MicroMounts™ for the cost per month of a graduate student or technician. Let them spend their time in more productive activities.

2. Choose the right tool for the problem. Designs optimized for retrieving and mounting thin plates, rods and needles, and microcrystals, for cutting protein skins, and for dislodging crystals from substrates can deliver better results faster.

3. Get crystals from your earliest crystallization trials into the X-ray beam as soon as possible, even if the crystals are ugly. If the diffraction falls off rapidly with angle (i.e., if the Wilson B factor is bad), you’re most likely going to have to modify your protein and/or do more purification. Don’t waste precious time and money using optimization screens in the hopes of getting bigger and better crystals. Triage early and often.

4. Screen the diffraction of your crystals at room temperature using MicroRT™ capillaries and our goniometer bases, before cryoprotecting them, and preferably before taking them to the synchrotron. One study found that more than 95% of protein cryocrystallography data sets collected at synchrotrons don’t yield data of sufficient quality for structure determination. We’re wasting our time and an expensive resource.

Collect a few short-exposure frames on your home source, just enough to get a rough estimate of the diffraction quality and also to check for excessive radiation damage in each frame. Be sure to account at least qualitatively for sample volume and cell size (tiny crystals with big cells diffract weakly, even when they’re well ordered.)

Crystals that initially (i.e., before radiation damage accumulates) diffract poorly at room temperature always diffract poorly at low temperature. Don’t waste time cryoprotecting and screening crystals at cryo temperatures if they don’t diffract at room temperature.

5. Remove residual mother liquor from around your sample by wicking and/or by dipping in LV CryoOil before flash cooling, and flash cool in liquid nitrogen using the hyperquenching protocol (Warkentin et al., J. Appl. Cryst. (2006) 39, 805-811) to eliminate ice rings and to ensure reproducible cooling conditions and low temperature diffraction outcomes. Following this protocol allows cryoprotectant soaks to be eliminated in most cases.

6. Standardize on a single pin / rod length – 18 mm/SPINE – and stop using hard-to-handle 10/11 mm lengths. MiTeGen’s B3S copper-post-style goniometer bases / caps accept 18 mm /SPINE lengths, so if you like copper post bases there’s no longer any need to use short rods.

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