Introduction

This site has been designed to aid the user in analysing protein and/or DNA crystal screening trials, interpreting their results, and planning subsequent optimization trials. The screening analysis tools include commonly used recipes from a number of manufacturers, (eventually) including: Emerald Biosystems, Hampton Research, Jena Biosciences, Molecular Dimensions, Qiagen, and Sigma. You also have the option to include your own screens without needing an account.

This project was originally started to try and determine the optimal buffer for a protein I was working on as a new post-doc, which precipitated at concentrations higher than ~6mg/mL. I wanted to find a methodical way of improving the storage buffer, and so maintaining a stable protein at concentrations typcially used in protein crystallization. The methodology is based on papers by Collins et al., and Jancarik et al. (see refs below). I basically wanted to see if there were common reagents in a crystal screen which yielded clear drops after 1 day and 1 week, respectively. From this, I could have a good idea of what buffer components my protein liked/disliked. To have a decent sample size, this requires at least one 96 condition screen, and given that commercial screens generally use space matrix technology, there is low overlap of conditions. There are great web servers and stand-alone programs out there which can analyze screening results, and even help in optimization (CLIMS, CRYStool, XAct, XtalBase, Xtrack - plus others); however, I wanted a simple point-and-click system which just analyses screening trials, and gives an easy to read summary of which components of a screen keep the protein "happy". Undeterred, I wrote some PHP code and an HTML front end to search a database of screens in the laboratory I was at.

To cut a long story short, I stopped working on the project before I had chance to really test the practicality of the method for myself.

While I was waiting my visa to be processed I spent time developing the code to examine all drop appearance types; this also looks to see if certain reagents are destabilizing the protein (i.e., causing heavy precipitation), and it doesn't ignore promising conditions which could be optimized to yield diffracting crystals, such as light precipitate and phase separation. Even if the conditions analysis tool isn’t used, it makes a nice record of your trays to print out and stick in your lab notebook!

I have also written a few other tools, such as the salt crystal predictor and quick lookup tool, which might be useful to new and experienced crystallographers alike!

While I have free time, I will continue to develop this web server. Please contact me using the e-mail address below with any comments, suggestions, or to report bugs.