So far most of my posts have focused on the science theory behind X-ray crystallography. But what of the people, both user and staff, who use the beamlines to produce such fanciful structures as this yeast betaprime COP 1-304H6 beta propeller pictured below.
Search 2YNO in the PDB for more details
Upon arriving at diamond its straight to reception to get a site pass and then on to the user office to get your access card for the synchrotron and beamlines, providing you’re not arriving the night before for a shift in the morning; then it’s off to Ridgeway House or another one of the hotels you may be sent to.
Lets assume you all know what staying in a hotel is like and move along to what actually happens at a beamline. First you will meet your friendly neighbourhood beamline scientist who will go through what is new on the beamline, how well the beamline has been operating and then give you a safety induction and some forms to sign. The main component of this is being showed how to search the hutch. For more details on the experimental hutch please see the previous post. It’s a pretty simple search, first swipe your access card, then walk to the back of the hutch, check for any people that may be hiding in the hutch and press a few little white buttons as you go. Make sure not to press the big yellow button pictured below.
Emergency beam off button: Not to be mistaken for the search buttons.
Once all of that is out of the way and papers have been signed it’s time to start loading samples. Some users will have samples preloaded in pucks, others will bring them in canes and load them into pucks at the beamline. Either way you will be greeted with a plethora of tools for all your sample loading needs.
From the bottom going clockwise we have protective gloves to prevent liquid nitrogen burns (not entirely effective), more gloves in latex/ nitrile form, safety glasses, a hair dryer, ethanol, water and compressed air, various tongs and such, the all important blue roll, pipettes and tips, puck tools and finally pucks.
Start off by filling up some foam dewars (blue and purple things at the bottom of the picture above) from a tipping dewar such as this:
Next cool down your pucks in the liquid nitrogen filled dewar:
Foam dewar and cooled uni pucks
Transfer your samples on canes from your travel dewar to a tall foam dewar:
Protein samples on pins in liquid nitrogen filled vials on a cane.
These samples are then placed into pucks and the pucks are then transferred to the large liquid nitrogen dewars in the experimental hutch ready for the robot to load the samples. In the last post I meant to get a robot picture but forgot so here you go.
Left: beamline set up with goniometer, liquid nitrogen stream etc. Right: Sample handling robot and 2 Liquid nitrogen dewars for sample storage.
Once you’ve got everything loaded into the dewars you do your hutch search just like your friendly neighbourhood beamline scientist taught you and you’re ready to fry some crystals with X-rays. Now all you’ve got to do is remember your FED ID and password which consist of many random letters, numbers and symbols in no particular order and your good to go. Once you’ve inevitably had to scroll through many e-mails to find IDs and passwords it’s time to get comfy because it’s probably going to be a long night. For how every many hours (8, 16 or 24 usually) you’ll be looking at this (see below). Top left screen is the beam status and the all important canteen is open/ closed window. Top right is your last diffraction image and videos of the robot and goniometer to make sure they’re doing what they should be doing. Bottom left is the GDA client where you tell the beamline how many images to take, what sort of rotation, resolution, beam intensity etc. Bottom right, more of a wild card, put what ever you like there but generally its ADXV or ALBULA, 2 programs used to looks at your diffraction patterns up close.
More screens than you can shake a stick at.
So from here its essentially the same thing all night, you tell the robot to load your sample and then head over to this screen (below) in the GDA where you centre your sample by clicking on the crystal and then rotating 90 degrees and repeating until happy. Then its over to the experimental control where you take 2-3 test shots and a data set if all goes well.
Sample centring screen: Crystal on a micromount, red circle is where your beam is hitting it, stuff to the left is used for centring. Click away until you’re happy.
Now its just a matter of refreshing this web page (below) to watch the graphs go up and down until it’s time to load another sample. This can happen anywhere between 8-45 minutes, or more, depending on the beamline you’re on and the number of images you want to collect.
Now you know what it’s like to spend a day as a crystallographer, but don’t let that deter you. It’s all worth it when you get some good results and a pretty structure to call your own. Or that’s what I’m telling myself until it happens.
Until next time thanks for reading.