Tiny protein crystals were studied by a global research team using short X-ray light pulses from the 300 million dollar Linac Coherent Light Source, which is the world’s first X-ray free electron laser. The study shows the great potential of free-electron lasers for observing macromolecular structures from very small crystals when lit up with highly intense, ultra-short, free-electron X-ray pulses even though the crystals get destroyed during the process.
In the present study, details from their structural analysis have shown results with spatial resolution of two millionth of a meter. The research team comprises researchers from the Max Planck Advanced Study Group in Hamburg and the Max Planck Institute for Medical Research in Heidelberg and they proved that their data was in line with the data obtained from well-characterized, large crystals using traditional X-ray sources, offering a benchmark for the novel free-electron laser approach. This experiment has established that the free-electron laser is an essential tool for structural biology on large macromolecular assemblies and membrane proteins, a large number of which are key targets for pharmaceutical development.
X-ray free-electron lasers are highly powerful new X-ray sources that offer very intense extremely short light flashes. The X-ray pulse intensity is over a billion times higher than that offered by the most brilliant sophisticated X-ray sources with a pulse length 1000 times shorter at the order of a few millionths of a billionth of a second or femtoseconds. These characteristics will offer scientists innovative tools to study the nano-world including the biological material structure.
This serial femtosecond crystallography technique was shown even previously by the same research team, however the comparatively long wavelength X-rays available then restricted the attainable structural detail level.
Of late, a novel instrument at the Linac Coherent Light Source, the Coherent X-ray endstation has enabled the usage of short wavelength X-rays and helps determine atomic details in the molecular architecture. In order to benchmark the method, a model system was studied, the small protein lysozyme, the first enzyme to have the structure was revealed.
Ten thousand snapshot exposures from crystals, which measured only a thousandth of a millimeter were collated and proved that the data could be compared with those obtained from traditional approaches and 100-fold larger lysozyme crystals. It must be noted that there were no signs of radiation damage.
Source: http://www.mpg.de