VMXi to VMXm Pipeline

Microcrystals that form in crystallisation plates stored at VMXi can now be flagged for data collection at VMXm. 

VMXi and VMXm while sharing parts of their names are very different in their capabilities. VMXi provides in-situ room temperature data collection, which can be useful for fragile crystals or room temperature based studies. However, a drawback is that the experiment has higher background noise due to the presence of the mother liquor in the droplet and the crystallsation plate. This can make it difficult to measure diffraction from crystals <20 µm in size. On the other hand, VMXm is optimised to maximise the signal-to-noise from weakly diffracting microcrystals where crystals are mounted on grids with minimal liquid and an in vacuum sample position. As such there is now a pipeline to flag samples in VMXi that would benefit from collection at VMXm.

1. Identify microcrystals in plate at VMXi.
2. Score microcrystal droplet '6 - Microcrystals'.
3. VMXm staff review images of droplet.
4. If the sample is appropriate for VMXm, the user will recieve an email notifiying them.
5. With permission VMXm staff will take the plate from VMXi and prepare grids of the microcrystals.
6. A sample based data collection session will be created at VMXm.
7. VMXm staff will screen the microcrystals, attempting to collect a complete dataset where diffraction occurs.
8. VMXm staff inform user of outcome of the data collection session.

Screen capture of the ISPyB interface of a plate stored at VMXi. In the top left of the droplet image you can score the droplets. Those scored as '6 - microcrystals' will be flagged to the VMXm team

In the ISPyB plate interface, it is possible to classify the droplets of crystallsation outcomes into a number of categories. If you identify a droplet as a microcrystal, please select '6 - microcrystals' from the score drop down in the top left of the droplet image view. Droplets flagged as microcrystals will be flagged to the VMXm team who will then assess the microcrystals for their suitability for collection at VMXm.

The above sample as scored as microcrystals in VMXi. These were prepared for VMXm and data were collected. A complete dataset at 2.79 Å resolution was assembled from a several smaller datasets collected from multiple crystals. The panel to the right is at maximum zoom in the ISPyB interface.

Microcrystals of a new structure identified in VMXi plates. These needles too small for VMXi, are ideal for VMXm. This example diffraction to 2.1Å. The panel to the right is at maximum zoom in the ISPyB interface.

These microcrystals look well formed, however, they only diffracted to 6Å. This was still a useful case as it informed the user they had formed protein crystals and could use this result as a basis for crystal optimisation. The panel to the right is at maximum zoom in the ISPyB interface.