January 27, 2010 20:48
This is exciting news: our PlugMaker protein crystallization instrument won the 2010 New Product Award at LabAutomation! Of course we've always known that this instrument is a winner: 800 crystallization setups with just 3-4 uL of proteins, with crystals ready to diffract and 'simple as an iPod'. Seeing now the independent stamp of the Association for Laboratory Automation on it is very gratifying to us.
Here's a big THANK YOU !!! to the many people and their brilliant minds behind this instrument: the team at BioStructures and BioSystems, especially Lance and Cory, Rustem's lab and our development partners. I'm looking forward to see many protein scientists produce lots of X-ray structures with protein crystals grown within CrystalCards using the PlugMaker.
Plugs are the new drops.
January 26, 2010 00:40
What's the new thing that people are tying out these days? Lots of new methodologies, ranging from low-volume plug-based crystallization (of course) to new crystallization screening matrices for membrane proteins. I've noticed that there's a 'new' seeding method around that has come up in several conversations I've had with protein crystallizers over the past 3 years or so. It's called Microseed Matrix Seeding. Judging from people who try and stick with it, it is my impression is that this seems to be working rather well.
What is Microseed Matrix Seeding in practical terms?
You start with a 'failed' primary protein crystallization tray and:
- Harvest some or all the precipitated drops, pool them (yes!) and call this seed stock.
- Spike each drop of a new, secondary crystallization trial with a portion of the seed stock.
- Obtain crystals from a protein/formulation combination that is different from that you used to create the seed stock with.
The Matrix Microseeding method and its application to yeast cytosine deaminase was first described by Gregory Ireton and Barry Stoddard in:
G. Ireton & B. Stoddard
Microseed matrix screening to improve crystals of yeast cytosine deaminase
Acta Cryst D60 (2004), 601-605.
Then Alan D'Arcy picked up on this new method and initiated a robotic application for this new protein crystallization seeding method:
A. D'Arcy, F. Villarda, M.Marsh An automated microseed matrix-screening method for protein crystallizationActa Cryst D63 (2007), 550-554.
Seeding with 'crap'? (mind me - not my own words, but I've heard this very question more than once)
Maybe not. What you see as precipitated material may be not properly characterized crystalline material. For all I know, there could be sub-micrometer sized microcyrstalline protein material mixed in the precipitate. And there's just no way for you to see that. Alternatively, the precipitated protein material itself may form a heterogenous nuclation surface in similar ways that seaweed or horse hair can serve as nuclei for protein crystallization.
A case for Microseed Matrix Screening(?)
If you you've got many drops with precipitation in it (B), and no crystallization leads whatsoever - why not try give it a try?
January 7, 2010 03:35
Guess what - in my opinion there was not a single paper published in 2009, covering the topic of protein crystallization review-style, that comes close to Naomi & Emmanuel's collected wisdom published in 2008:
As much as I prefer open-source publications, this is one of the best. Nature Methods, Vol. 5 No.2, February 2008. Naomi Chayen and Emmanuel Saridakis.
Because it covers all the basics: Setting up initial protein crystallization trials and classical screening methods, deals with the question how many trials should be set up, what ideal volumes are and what to do if protein crystallization trials fail. In addition, Naomi Chayen and Emmanuel Saridakis lucidly explain the choices of available crytallization formats and go into a fairly detailed description of practical ways to influence the crystallization process to grow protien crystals that are sufficient for X-ray diffraction . Protein crysallization optimization is explained in a hands-on fashion, extensively referencing the body of published literature. A joy to read.
I've saved this paper in my archive using the file name Naomis_bible_paper.pdf
Happy new 2010!