Investigation of the structure of scorpion hemocyanin using X-ray crystallography and bioinformatical methods.

Solving crystal structures of biomolecules is an important method in the research groups of Decker/Jaenicke and Stöcker in order to learn more about the function of these biomolecules on an atomic level. An example is hemocyanin. Hemocyanins are respiratory multimeric proteins, which reversibly bind molecular oxygen between two copper atoms. These oxygen carriers can be converted into enzymes. This class of enzymes (tyrosinases, catecholoxidases) is responsible for the color of skin and hair in humans and animals, as well as the browning of arthropods, plants and mushrooms. It is unclear, to what extent this functional change is caused by a conformational change in the hemocyanin.

Using molecular dynamics, we were able to provide a possible explanation for albinism and the graying of hair on a molecular level. First insights into the molecular mechanism of activation were deduced from the 24-meric hemocyanin from the scorpion Pandinus imperator by cryo electron microscopy. By means of small angle scattering, electron density maps of the different states were already calculated. However, these do not allow an atomic interpretation and analysis of the intramolecular pathways within these cooperative oligomeric proteins. Therefore a higher resolution, which can only be achieved by X-ray crystallography, is in progress. This is the basis for applying molecular dynamic methods to solve the mechanism of the catalysis.