Protein Crystal Screening Service
X-rays interact with biological macromolecules weakly and therefore diffraction from a single protein molecule will be difficult to detect. However, a three dimensional crystal with tens of thousands of ordered macromolecules will enhance the signal many times thereby making it possible to record a diffraction pattern. Despite the enormous progress structural biologists have made in solving protein structures, obtaining protein crystal is still hard and knowing a priori condition in which a protein will crystallize is still not easy. That is why we need to screen several conditions to find one that will crystallize the macromolecule or its complex.
Since 2009, X-Ray Facility has been providing protein crystal screening service (PCSS). PCSS was essentially a manual batch screening of 96 individual crystallization screen conditions (selected either by the user or the Facility) for a target protein at room temperature. The screens will then be visually inspected at set times, scored and the results summarized for the user. Optionally, the user can request a Pre-Crystallization Test (PCT) be performed before beginning screening service to determine whether concentration of the protein being provided for screening is at optimal concentration required for screening. A user fee structure has been added to recoup the cost of the consumables for PCSS.
To speed up the crystallization screening process, to reduce the errors involved in manual screening, and to explore more crystallization space with less macromolecule, on Monday, July 28, 2014 we have installed the Art Robbins Instruments Crystal Gryphon @ FSU 96-well crystal set-up robot. The XRF provides this service with all consumables provided by the user.
In August 2018, XRF acquired Rock Imager 01 manufactured by Formulatrix that is compatible with SBS, 96-well (ARI), and Linbro plates. Rock Imager allows the automated imaging of plates and works with Rock Maker software. Rock Imager 01 has a single light path and has both visible and ultra-violet (UV) light capabilities. It has bar code scanner so plates created using Rock Maker and Formulator 16 can be read and either manually or automatically imaged at regular intervals.We have also added Formulator 16 manufactured by Formulatrix which allows custom screen building and dispenses the screens using microfluidic technology. It can support 15+1 (water) ingredients and has a 96 nozzle dispensing the drops. Very low volumes of 200 nL to high volumes in few mL are achievable.
In January 2016, we started to offer automated scanning and storing of images of 96-reservoir-3-well or 96-reservoir-2-well ARI Intelliplate crystallization screens using our IMB-designed home-built Simple Robotic Imager (SRI). The robotic imager is housed in KLB 412 and is shown on the right collecting data on an ARI 102-0001-20 using a Linux computer. For ARI 96-reservoir-2 well plate (ARI# 102-000-20) it will take about 8 minutes to image all the 192 wells at about 90x magnification. For ARI 96-reservoir-3 well plate (either ARI# 102-000-13 or ARI# 102-000-03 ) it will take about 12 minutes to image all the 288 wells at about 120x magnification. As soon as the image collection is over it can be viewed using Linux feh image viewer program.
We are working on the second version of the imager with belts rather than threaded rod.
Updated: September 09, 2020.