Journal Article

FZJ-2016-07668

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Structural Evolution of Metastable Protein Aggregates in the Presence of Trivalent Salt Studied by (V)SANS and SAXS

Sauter, A. ; Zhang, F. (Corresponding author) ; Szekely, N.FZJ* ; Pipich, V.FZJ* ; Sztucki, M. ; Schreiber, F.

2016
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/acs.jpcb.6b03559

Abstract: We present a study of the structural evolution of protein aggregates formed in solutions of a globular protein, β-lactoglobulin (BLG), in the presence of YCl3. These aggregates are often observed before crystallization starts and they are metastable with respect to the crystalline phase. Here we focus on the characterization of the hierarchical structure of this intermediate phase and its temperature dependent structure evolution using a combination of (very) small angle neutron and X-ray scattering (VSANS, SANS, and SAXS). Results show that the hierarchical structure ranges from nanometer scale protein monomer, dimer and compact protein clusters to micrometer scale fractal protein aggregates. Upon cooling, the overall hierarchical structure is preserved, but the evolution of the internal structure within the aggregates is clearly visible: the monomer–monomer correlation peak reduces its intensity and disappears completely at lower temperatures, whereas the cluster–cluster correlation is enhanced. At a larger length scale, the fractal dimension of protein aggregates increases. The kinetics of the structure change during a temperature ramp was further investigated using time-resolved SAXS. The time dependent SAXS profiles show clear isosbestic points and the kinetics of the structural evolution can be well described using a two-state model. These dynamic properties of protein aggregates on a broad length scale may be essential for being the precursors of nucleation.

Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Biology (2nd) ; Soft Condensed Matter (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)

Research Program(s):

1. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. KWS-2: Small angle scattering diffractometer (NL3ao)
2. KWS-3: Very small angle scattering diffractometer with focusing mirror (NL3auS)

Appears in the scientific report 2016

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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