Domain Motions: Protein Dynamics seen by Neutron Spinecho Spectroscopy with Ralf Biehl

7 February 2024
This webinar is part of the Antibodies in Solution webinar series at LINXS.
Title: Domain Motions: Protein Dynamics seen by Neutron Spinecho Spectroscopy
Speaker: Ralf Biehl, Jülich Centre for Neutron Science (JCNS), Germany
Abstract: The biological function of proteins is often related to configurational changes and large-scale domain motions, which are induced or suppressed by the binding of a substrate or due to cosolvents. Domain motions can be related to soft hinges, flexible linker regions or - as in the case of intrinsically disordered proteins - be native to proteins without secondary or tertiary structure. These large-scale domain motions in solution cannot be observed by X-ray crystallography or NMR spectroscopy. Small angle scattering (SAS) by X-rays or neutrons in combination with neutron spin echo spectroscopy (NSE) in solution can be used to observe configurational changes and equilibrium dynamics between functional domains on 1-300 nanosecond timescale.
I will present examples for different types of motions related to the structure of proteins and bioconjugates. Thermal unfolded Ribonuclease A shows polymer like dynamics despite the 4 disulfide bonds restricting the degrees of freedom. Prior to full unfolding the protein unfolding dynamics is observed. Polyelectrolytes have structural and dynamical similarities with IDP. The domain protein Phosphoglycerate kinase shows a hinge motion between the main domains related to function. PEGylation seems not to influence this domain motion but adds additional internal dynamics in the protein-polymer complex. Antibodies present a strong dynamics due to the short linkers connecting the Fc with the Fab domains. The observed dynamics is related to internal forces, solvent friction and the role of charge screening.