SMALL ANGLE NEUTRON SCATTERING FOR STRUCTURAL BIOLOGY OF CHALLENGING BIOMACROMOLECULAR COMPLEXES

by Dr Frank Gabel (IBS & ILL, Grenoble, France)

Monday 12 Nov 2018, 14:30 → 15:30 Europe/Berlin

HS 3 (Physics Department)

Small angle neutron scattering (SANS) provides unique insight into biomacromolecular complexes by combining solvent contrast variation (H2O:D2O exchange) with either natural contrast between different classes of biomolecules (proteins, RNA/DNA, lipids/detergents) and/or by applying artificial contrast, i.e. deuteration of specific biomolecules. I will present several biological projects where SANS has played a crucial role by providing unique restraints for structural refinement and interpretation, complementary to NMR, SAXS, crystallography and EM.

1. a first example, I will show how distance and shape restraints from SANS have helped to improve the uniqueness of structural models for two multi-protein-RNA complexes, in combination with NMR restraints and building blocks from crystallography [1, 2]. In a second example, the stoichiometry and internal topology of a highly symmetric, hetero-dodecameric aminopeptidase enzyme complex is revealed by SANS, and conclusions on the assembling process can be drawn in combination with EM data [3]. Other examples will include structural studies of two solubilized membrane proteins and their detergent belts [4, 5], a time-resolved study of the active unfolding of GFP by an unfoldase complex [6], and insight into the hydration shell properties of proteins [7].

1. I will present two recent developments that will improve the quality and accuracy of SANS data: one the one hand, segmental deuteration which allows to access more detailed structural information for the important class of multi-domain proteins [8], and on the other hand size-exclusion chromatography (SEC) coupled to SANS, which improves sample quality, and in particular monodispersity [9].

 

References

[1] Lapinaite et al. (2013) Nature502(7472), 519-523.

[2] Hennig et al. (2014) Nature515(7526), 287-290.

[3] Appolaire et al. (2014)Acta Cryst. D70(Pt 11), 2983-2993.

[4] Gabel et al. (2014) Biophys. J.107(1), 185-196.

[5] Dias-Mirandela et al. (2018) J. Phys. Chem. Lett.9(14), 3910-3914.

[6] Ibrahim et al. (2017) Sci. Rep.7, 40948.

[7] Kim et al. (2016) Biophys. J.110(10), 2185-2194.

[8] Sonntag et al. (2017) Angew. Chem.56(32), 9322-9325.

[9] Jordan et al. (2016) J. Appl. Crystallogr.49(Pt 6), 2015-2020.