title: Monomeric Amyloid Beta Peptide in Hexafluoroisopropanol Detected by Small Angle Neutron Scattering.
abstract: Small proteins like amyloid beta (Aβ) monomers are related to neurodegenerative disorders by aggregation to insoluble fibrils. Small angle neutron scattering (SANS) is a nondestructive method to observe the aggregation process in solution. We show that SANS is able to resolve monomers of small molecular weight like Aβ for aggregation studies. We examine Aβ monomers after prolonged storing in d-hexafluoroisopropanol (dHFIP) by using SANS and dynamic light scattering (DLS). We determined the radius of gyration from SANS as 1.0±0.1 nm for Aβ1-40 and 1.6±0.1 nm for Aβ1-42 in agreement with 3D NMR structures in similar solvents suggesting a solvent surface layer with 5% increased density. After initial dissolution in dHFIP Aβ aggregates sediment with a major component of pure monomers showing a hydrodynamic radius of 1.8±0.3 nm for Aβ1-40 and 3.2±0.4 nm for Aβ1-42 including a surface layer of dHFIP solvent molecules.
authors.affiliation: Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Research Centre Jülich, Jülich, Germany.|Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang-Haagen
authors.affiliation: Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Research Centre Jülich, Jülich, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Biehl
authors.affiliation: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.|Institute of Complex Systems, Structural Biochemistry (ICS-6), Research Centre Jülich, Jülich, Germany.
authors.forename: Luitgard
authors.initials: L
authors.lastname: Nagel-Steger
authors.affiliation: Jülich Centre for Neutron Science, Outstation at MLZ (JCNS-MLZ), Research Centre Jülich, Garching, Germany.
authors.forename: Aurel
authors.initials: A
authors.lastname: Radulescu
authors.affiliation: Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Research Centre Jülich, Jülich, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Richter
authors.affiliation: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.|Institute of Complex Systems, Structural Biochemistry (ICS-6), Research Centre Jülich, Jülich, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Willbold
mesh_terms: D016229:Amyloid beta-Peptides / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D057446:Hydrodynamics; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008958:Models, Molecular; D033363:Neutron Diffraction; D010446:Peptide Fragments / Q000032:analysis* / Q000737:chemistry; D020005:Propanols; D066263:Protein Aggregation, Pathological; D011487:Protein Conformation; D053838:Scattering, Small Angle; D012997:Solvents; D006845:Hydrocarbons, Fluorinated
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D020005:Propanols; D012997:Solvents; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42); C001337:hexafluoroisopropanol; D006845:Hydrocarbons, Fluorinated