Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 1: Protein Structure and Dynamics
BP 1.7: Vortrag
Montag, 12. März 2018, 11:30–11:45, H 1028
The relevance of conformational entropy for ligand-protein interactions: The case of biotin and streptavidin — •Mona Sarter1,2, Andreas Stadler1, Doreen Niether1, Bernd König1, Simone Wiegand1,3, Jörg Fitter1,2, Michaela Zamponi1, Wiebke Lohstroh4, and Niina Jalarvo5 — 1FZJ Jülich — 2RWTH Aachen — 3Universität zu Köln — 4TUM München — 5SNS Oak Ridge
Molecular dynamics play a vital role for the biological function of proteins. For protein ligand interactions changes of conformational entropy of the protein and the hydration layer are relevant for the binding process. In an experimental study we investigated the relevance of conformational entropy for the binding of biotin to the protein streptavidin. In order to investigate the proteins conformational entropy and dynamics quasi elastic neutron scattering (QENS) was used, for the protein and hydration layer isothermal titration caliometry (ITC) was used and for the hydration layer thermodiffusion (TDFRS) was used.
QENS results show that the conformational entropy of streptavidin is reduced upon biotin binding, while ITC results show that the conformational entropy of the hydration layer increases upon biotin binding. TDFRS results also indicate an increased entropy of the hydration layer. This leads to the conclusion that the hydration layer plays an important role in stabilising the binding of biotin to streptavidin. The internal streptavidin dynamics before and after biotin binding were compared. This showed that the flexibility of streptavidin is greatly reduced upon biotin binding leading to the complex being more rigid.