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3|2012 Research in Jülich 9 COVER STORY | Neutrons 35°34°33° tween Jülich researchers and scientists at these neutron sources. “My PhD thesis, on which I started working in 2006, was joint- ly funded and supervised by Jülich and ILL,” says Andreas Stadler. It became his task to perform neutron scattering experi- ments on haemoglobin at ILL, thus imple- menting Büldt’s idea. OBSERVING ATOM MOVEMENTS Stadler used a neutron backscatter- ing spectrometer that measures how the atoms move in the haemoglobins at dif- ferent temperatures. “The instrument I used, which is referred to as IN13, is able to monitor the tiniest of movements occurring within a hundred trillionth of a second,” explains Stadler. However, the atoms in haemoglobin do not move free- ly – they are chemically bound to other atoms. Measurements of atom mobility therefore provide information on wheth- er the entirety of chemical bonds in the haemoglobins reacts elastically or rigidly to changes in temperature. “During a scientific conference in France, where I presented my PhD pro- ject, I met Chris Garvey, a scientist from Australia,” says Stadler. Garvey was very interested in Stadler’s research. As soon as the two scientists had agreed to co- operate, Garvey made efforts to obtain blood samples from platypuses – a pro- tected species – and from crocodiles. The most important result of the measurements: the haemoglobins of dif- ferent species differ in their degree of flexibility. The haemoglobin of the platy- pus, which has a low body temperature, is soft and flexible. The haemoglobin of “hot-blooded” chickens is much more rigid. Humans fall somewhere in be- tween these two extremes, not only in terms of their body temperature, but al- so the flexibility of their red blood cells. “Our measurements confirm that hae- moglobin is a highly sensitive molecular thermometer of body temperature,” says Stadler. In an independent research pro- ject, Artmann from Aachen University of Applied Sciences also demonstrated an- other way in which human red blood cells react to temperature: they begin to release cellular water into the blood at temperatures above 37°C. The Jülich scientist Stadler, however, is not only concerned with the subject of his research – haemoglobin – but also the research method. “In contrast to our approach, neutron researchers often measure proteins in the form of slightly wetted powders instead of in aqueous solutions,” he says. The most important reason for this is that in the solution, the entire protein moves, not just the atoms inside the protein. This is why it is often difficult to analyse such measurements. In the case of the haemoglobins, howev- The Institut Laue-Langevin in Grenoble is a leading international centre for neutron re- search and collaborates closely with Forschungszentrum Jülich. PLATYPUS 33°C