Unravelling the building blocks of life
When a Russian Progress craft docked with the International Space Station on 23 August 2001, it brought Europe’s second scientific experiment – the Granada Crystallisation Box (GCB.
From the outside it is not particularly impressive because, as its name suggests, it is a box, and quite a small one – just 13 cm by 13 by 8, weighing about one kilogramme on Earth. The concept on which the GCB was developed by the team of Prof. J.M. Garcia Ruiz of the CSIC-University of Granada, stems from experimental and numerical research work into the process of protein crystallisation jointly supported by ESA and CSIC.
Growing crystals of biological macromolecules enables scientists to unravel the details of their structure by X-ray diffraction analysis – the better the crystals, the higher the level of detail they provide under the X-ray beam.
The GCB concept uses a technique known as ‘counter-diffusion’, which features long capillaries filled with a solution of the molecule to be crystallised. When precipitant is left to diffuse into the capillary, a broad range of conditions for growing crystals is automatically scanned within one single experiment.
Although very efficient on the ground, experimental work with optical diagnostics has identified the occurrence of convection currents – the weightless environment of the Space Station, however, will allow crystals to form without any interference from gravity-induced convection currents.
The flight-test of the GCB, which involves several molecules contributed by different European laboratories, aims to contribute to the development of models correlating the quality of crystals with their growth conditions. These will form the basis of the predictive tools needed for future experiments.
The CGB team will not have too long to wait for their results. Right now, their experiment is nestling in a quiet corner of the Space Station, requiring neither power nor attention from the crew. When the Andromède mission returns to Earth it will carry the small box. Its capillary tubes – which can be X-rayed directly, without removing their fragile contents – may reveal some secrets.
Last update: 25 October 2001