Journal Article

PreJuSER-18198

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Strong stabilization of liquid amorphous calcium carbonate by ovalbumin: gaining insight into the mechanism of 'polymer-induced liquid precursor' processes

Wolf, S. ; Leiterer, J. ; Pipich, V.FZJ* ; Barrea, R. ; Emmerling, F. ; Tremel, W.

2011
American Chemical Society Washington, DC

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Please use a persistent id in citations: doi:10.1021/ja202622g

Abstract: The impact of the ovo proteins ovalbumin and lysozyme--present in the first stage of egg shell formation--on the homogeneous formation of the liquid amorphous calcium carbonate (LACC) precursor, was studied by a combination of complementing methods: in situ WAXS, SANS, XANES, TEM, and immunogold labeling. Lysozyme (pI = 9.3) destabilizes the LACC emulsion whereas the glycoprotein ovalbumin (pI = 4.7) extends the lifespan of the emulsified state remarkably. In the light of the presented data: (a) Ovalbumin is shown to behave commensurable to the 'polymer-induced liquid precursor' (PILP) process proposed by Gower et al. Ovalbumin can be assumed to take a key role during eggshell formation where it serves as an effective stabilization agent for transient precursors and prevents undirected mineralization of the eggshell. (b) It is further shown that the emulsified LACC carries a negative surface charge and is electrostatically stabilized. (c) We propose that the liquid amorphous calcium carbonate is affected by polymers by depletion stabilization and de-emulsification rather than 'induced' by acidic proteins and polymers during a so-called polymer-induced liquid-precursor process. The original PILP coating effect, first reported by Gower et al., appears to be a result of a de-emulsification process of a stabilized LACC phase. The behavior of the liquid amorphous carbonate phase and the polymer-induced liquid-precursor phase itself can be well described by colloid chemical terms: electrostatic and depletion stabilization and de-emulsification by depletion destabilization.

Keyword(s): Animals (MeSH) ; Calcium Carbonate: chemistry (MeSH) ; Calcium Carbonate: metabolism (MeSH) ; Chickens (MeSH) ; Crystallization (MeSH) ; Egg Shell: chemistry (MeSH) ; Egg Shell: metabolism (MeSH) ; Emulsions: chemistry (MeSH) ; Emulsions: metabolism (MeSH) ; Muramidase: chemistry (MeSH) ; Muramidase: metabolism (MeSH) ; Ovalbumin: chemistry (MeSH) ; Ovalbumin: metabolism (MeSH) ; Health and Life (1st) ; Health and Life (1st) ; Biology (2nd) ; Emulsions ; Calcium Carbonate ; Ovalbumin ; Muramidase ; J

Note: We thank Simone Rolf and Ralf Bienert (BAM) for technical support at the beamline. We are much obliged to Frederic Mann and Ute Schlossmacher for assistance in IG labeling and fruitful discussions. We are grateful to the Deutsche Forschungsgemeinschaft (DFG) for support within the priority program No. 1415: "Kristalline Nichtgleichgewichtsphasen". S.E.W.gratefully acknowledges the Konrad Adenauer Foundation for a doctoral fellowship. We thank the BioCAT team at the Advanced Photon Source for excellent support during XAS experiments, and we are grateful to Dr. David Gore for his careful revision of the English style. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE), Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. BioCAT is a National Institutes of Health-supported Research Center RR-08630.

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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)
4. Streumethoden (JCNS-2)

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-1: Small angle scattering diffractometer (NL3b)

Appears in the scientific report 2011

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