Yesterday morning I awoke in crumpled clothes on a strange sofa, my mouth feeling furry and unwashed. I’d crashed there at about 5.30 am and only snatched a couple of hours of fitful sleep. As I gazed blearily at unfamiliar surroundings, a woman I barely recognised appeared and asked if I’d like a cup of tea. I nodded and mumbled thanks.
The symptoms will be familiar to most protein crystallographers: puffy eyes, grey complexion, mental derailment, churned up guts that are no longer in sync with mealtimes. Jet-lag without ever having left the ground.
Three of us had arrived bright-eyed on Wednesday morning for our first data collection trip on the micro-focus beam-line (I24) at Diamond. The beam-line is a work in progress since the experimental station isn’t quite fully operational. But it works well enough to be useable and in a mutual back-scratching agreement with Gwyndaf, the beam-line scientist, we’d managed to snag some time for our project. I24 focuses the intense X-rays generated by the accelerator ring into a beam that is only about a tenth of the thickness of a human hair—around 10 µm—just what we needed since our crystals were tiny needles of about the same size.
It’s amazing that such miniscule crystals can be used to scatter X-rays into the diffraction patterns needed to figure out the structure of the molecules within. But tiny crystals make for tricky experiments. So we fiddled for hours, scooping up each one and freezing it in a stream of nitrogen cooled to 100K. The frozen crystal—trapped in a gobbet of cryo-solvent—is imaged by a microscope so that we can manoeuvre it precisely into the path of the beam. But seeing a tiny crystalline shard embedded in a glistening bead that bends and reflects the light is no easy feat.
Even then the X-rays are so intense and the crystals so small that ten short exposures were enough to frazzle the protein. So you stop and shift the crystal needle along to blast a new section for another 10 exposures.
And so the night passed, myself, Olga and Jingjie locked in intense rounds of sample preparation and analysis, of activity and concentration. We were cheered when rows of dark spots appeared on the detector, dismayed when there were none. Midnight came and went and the wee small hours were upon us. It’s strange, but you can keep going as long as you’re active, as long has you have a purpose.
But we finished around 5 am, tidied up and crashed. And when you do stop your body finally catches on to the punishment you’ve been giving it and strikes back with a vengeance. We slunk back dead-beat from Diamond.
The name was well chosen: diamonds are bright but they’re also hard. Well hard.