There are so many parameters to change when optimizing crystallizations and they all need to be tried out to identify the critical parameter that improves X-ray diffraction. In this series of blog posts I've mostly discussed modulating the crystallization reaction, by adding additives, changing precipitant or protein concentration etc. However, there seems to be a simple way to optimize, keeping all other parameters constant: drop volume, temperature, all concentrations. What could it be?
Try switching the crystallization plate!
Jenny Martin describes in her recent PLOS paper with statistical rigour that different 96-well crystallization plates - formats, materials - do effect the outcome of protein crystallization experiments:
King, Gordon J., Kai-En Chen, Gautier Robin, Jade K. Forwood, Begoña Heras, Anil S. Thakur, Bostjan Kobe, Simon P. Blomberg, and Jennifer L. Martin.
Interaction between Plate Make and Protein in Protein Crystallisation Screening.
PLoS ONE 4, no. 11 (November 16, 2009): e7851
In fact, she suggests to optimize protein crystal growth by matching the protein with its optimal plate make.
Figure: Compare different protein crystallization plates to grow optimized protein crystals.
So, here's a selection of 6 different Emerald BioSystems protein crystallization plates with different formats, well arrangements, volumes and materials that you may want to try to optimize protein crystal growth:
Clover 384 plate (COC material, 4 micro crystallization wells / reservoir)
Clover 384 plate (Polystyrene, 4 micro crystallization wells / reservoir)
Compact Clover plate (Polypropylene, 4 crystallization wells / reservoir)
Compact, Jr. plate (Polypropylene, 1 crystallization well / reservoir)
Combi Clover plate (Polypropylene, large wells, 4 crystallizations well / reservoir)
Combi Clover Jr. plate (Polypropylene, large wells, 1 crystallization well / reservoir)
Sometimes it's time to change the game.