Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 1: Proteins I
BP 1.9: Vortrag
Montag, 26. März 2012, 12:15–12:30, H 1058
Solution structures and domain motions of human guanylate binding protein 1 — •Andreas Stadler1, Adrian Syguda2, Ralf Biehl1, Christian Herrmann2, and Dieter Richter1 — 1Forschungszentrum Jülich, ICS-1 & JCNS-1 — 2Ruhr-Universität Bochum
Human guanylate binding protein 1 belongs to the superfamily of large GTPases. The expression of the protein in cells is strongly induced by interferons and other cytokines and it plays an important role in immune response and tumor growth. The crystal structure shows three domains: a globular head which is responsible for catalytic activity, an α-helical middle domain and a long rigid α-helical H12/H13-domain along the whole protein. The protein hydrolyses GTP to GDP and to GMP. Different conformations of the protein can be trapped during the GTP hydrolysis in solution. In the course of GTP hydrolysis, concerted large scale motions between the LG and the H12/H13 domains occur, which affect the enzymatic reaction rate.
We determined the solution structures of the protein in the different conformations during GTP hydrolysis using small angle X-ray scattering. Additionally, we measured the amplitudes and relaxation rates of the domain motions in the nm length- and 100 ns time-scale using neutron spin echo spectroscopy combined with small angle neutron scattering. The obtained results are important for a detailed understanding of the biological function of the protein on a molecular level, as we gain direct insight into the correlation of the domain motions and the enzymatic reaction.