Microlytic: Crystal Former and SmartScreen

May 2, 2009

Protein crystallization:
Try varying: the precipitate, pH, salt, temperature, music, protein concentration, etc…
Try a different method: sitting drop, hanging drop, batch, etc…

I received an email from Microlytic, a company selling a unique machine called the Crystal Former. They were kind enough to answer a number of my questions regarding this product. They even let me in on a brand new product called the SmartScreen, which has yet to be listed on their website.

I’ve posted the correspondence between myself and Microlytic below. Hopefully, this answers a few questions some of you may have regarding their Crystal Former.

1) The price for your products are not listed online, do you have a price point determined for your trays?

We are working to have this product established as an important new tool for crystallographers. Your readers should contact us directly for price quotations. In the past, evaluators have received favorable pricing, with an understanding that they will share results, data with the company.

We offer SmartScreen, selected conditions from sparse screens, for use with the Crystal Former. This system, liquids and plates, should be viewed as a cost-effective, convenient method for crystallizing those hard-to-crystallize proteins or for optimizing proteins already crystallized using commercially available screens.

The gradient conditions of forming crystals should minimize the total number of screening conditions needed to produce beam-quality crystals; reducing the comparative cost per experiment.

2) From your products sheet : “The Crystal Former uses special materials, a unique surface treatment, and proprietary mixing kinetics to substantially improve crystallization success rate, as demonstrated in multiple model proteins.”

The plastic has been treated to make the surface hydrophilic. The mixing kinetics refer to molecular diffusion of salts, buffers and precipitants from one well into the capillary; and protein into the precipitant well, albeit at a slower rate. Bulk liquid flow of either component has been minimized by physical design and the materials used.

Anecdotally, the use of capillary conditions should give 2 – 8 times more crystals (sometimes more) than the vapor diffusive techniques, including microbatch.

Has the Crystal Former been able to crystallize a novel protein that had yet to be crystallized by another method?

Yes. This work was done at a large Pharmaceutical Company in the United States . I cannot give names. The researcher had set up several sitting drop plates and didn’t see crystals in any wells. He chose some of his favorite conditions from a screen already used to retest the protein using the Crystal Former. (Kimber et al, 2003). Crystals were produced.

Note: The Kimber article, which uses data mining for optimizing protein crystal screens, is worth reading unless crystallizing proteins is not a problem your lab

From this work, we now offer a 48 well screen, the SmartScreen, that were chosen as the best crystal producers from many of the commercially available screens and has been adapted for use with the Crystal Former. The cost is $95.00; enough solution for 50 screens (using the Crystal Former).

3) “We verified by X-ray diffraction at X6A beamline at NSLS at Brookhaven National Labs, that a representative subset of the crystals obtained using the Crystal Former™ were indeed protein crystals.”

We didn’t test all the crystals formed in the Crystal Former in the beamline, only a subset. We choose crystals at random from the wells. There may have been higher-quality crystals that were not analyzed by X-ray.

Have you compared the diffraction quality to other methods of crystallization?

We crystallized 3 well-characterized proteins; Thaumatin, Catalase and Myoglobin. The diffraction patterns from these crystals compared favorably with those in the published literature in spite of the Crystal Former crystallization conditions had not been optimized but were initial screening hits.

4) “Importantly, 36 of the conditions that gave crystal hits in the Crystal Former™ did not give rise to crystal hits in the sitting drop plates highlighting the significantly improved crystallization hit rate obtained by using the Crystal Former™.”

The process of producing crystals in the Crystal Former explores more of the phase diagram for the protein-precipitant mixture. The protein in solution is gently exposed to super saturation conditions leading to more crystals of beam quality.

Your results indicate better results compared to sitting drop, have you done comparisons with other techniques such as batch and hanging drop?

We would expect similar results when comparing Crystal Former (capillary) to any of the vapor diffusive techniques (hanging or sitting drop) or micro-batch. As the manufacturer of a novel device, we are always being compared to existing technologies. Other manufacturers of microfluidic devices, e.g. Fluidigm, have also done this comparison and they have reported similar results.

We are able to grow more crystals because of the gradient effects on proteins in solution. The Crystal Former design allows for easy harvesting of crystals.

If you would like more information, feel free to contact John Morrison at 781-376-0780 extension 226. I had the pleasure of talking with John before completing this post and he was very helpful.