Journal Article

PreJuSER-19773

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Hydration and interactions in protein solutions containing concentrated electrolytes studied by small-angle scattering

Zhang, F. ; Roosen-Runge, F. ; Skoda, M. W. A. ; Jacobs, R. M. J.FZJ* ; Wolf, M. ; Callow, P. ; Frielinghaus, H.FZJ* ; Pipich, V.FZJ* ; Prévost, S. ; Schreiber, F.

2012
RSC Publ. Cambridge

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Please use a persistent id in citations: http://hdl.handle.net/2128/7402  doi:10.1039/c2cp23460b

Abstract: During protein crystallization and purification, proteins are commonly found in concentrated salt solutions. The exact interplay of the hydration shell, the salt ions, and protein-protein interactions under these conditions is far from being understood on a fundamental level, despite the obvious practical relevance. We have studied a model globular protein (bovine serum albumin, BSA) in concentrated salt solutions by small-angle neutron scattering (SANS). The data are also compared to previous studies using SAXS. The SANS results for dilute protein solutions give an averaged volume of BSA of 91,700 Å(3), which is about 37% smaller than that determined by SAXS. The difference in volume corresponds to the contribution of a hydration shell with a hydration level of 0.30 g g(-1) protein. The forward intensity I(0) determined from Guinier analysis is used to determine the second virial coefficient, A(2), which describes the overall protein interactions in solution. It is found that A(2) follows the reverse order of the Hofmeister series, i.e. (NH(4))(2)SO(4) < Na(2)SO(4) < NaOAc < NaCl < NaNO(3) < NaSCN. The dimensionless second virial coefficient B(2), corrected for the particle volume and molecular weight, has been calculated using different approaches, and shows that B(2) with corrections for hydration and the non-spherical shape of the protein describes the interactions better than those determined from the bare protein. SANS data are further analyzed in the full q-range using liquid theoretical approaches, which gives results consistent with the A(2) analysis and the experimental structure factor.

Keyword(s): Animals (MeSH) ; Cattle (MeSH) ; Electrolytes: chemistry (MeSH) ; Neutron Diffraction (MeSH) ; Osmolar Concentration (MeSH) ; Protein Interaction Mapping (MeSH) ; Salts: chemistry (MeSH) ; Scattering, Small Angle (MeSH) ; Serum Albumin, Bovine: chemistry (MeSH) ; X-Ray Diffraction (MeSH) ; Health and Life (1st) ; Health and Life (1st) ; Chemistry (2nd) ; Electrolytes ; Salts ; Serum Albumin, Bovine ; J

Note: We gratefully acknowledge financial support from Deutsche Forschungsgemeinschaft (DFG) and the beam time allocation from ESRF, ILL, JCNS and Helmholtz-Center Berlin (BENSC). The beam time on V4 at the Helmholtz Zentrum Berlin has been supported by the European Commission under the 6th Framework Program through the Key Action: Strengthening the European Research Area, Research Infrastructures. Contract No. RII3-CT-2003-505925 (NMI3).

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Contributing Institute(s):

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

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Experiment(s):

1. KWS-2: Small angle scattering diffractometer (NL3ao)

Appears in the scientific report 2012

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Database coverage:
; ; Allianz-Lizenz / DFG ; Current Contents - Social and Behavioral Sciences ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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