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Local Crystalline Structure in an Amorphous Protein Dense Phase.

ABSTRACT: Proteins exhibit a variety of dense phases ranging from gels, aggregates, and precipitates to crystalline phases and dense liquids. Although the structure of the crystalline phase is known in atomistic detail, little attention has been paid to noncrystalline protein dense phases, and in many cases the structures of these phases are assumed to be fully amorphous. In this work, we used small-angle neutron scattering, electron microscopy, and electron tomography to measure the structure of ovalbumin precipitate particles salted out with ammonium sulfate. We found that the ovalbumin phase-separates into core-shell particles with a core radius of ?2 ?m and shell thickness of ?0.5 ?m. Within this shell region, nanostructures comprised of crystallites of ovalbumin self-assemble into a well-defined bicontinuous network with branches ?12 nm thick. These results demonstrate that the protein gel is comprised in part of nanocrystalline protein.

SUBMITTER: Greene DG

PROVIDER: S-EPMC4623890 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature

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Local Crystalline Structure in an Amorphous Protein Dense Phase.

Greene Daniel G DG Modla Shannon S Wagner Norman J NJ Sandler Stanley I SI Lenhoff Abraham M AM

Biophysical journal 20151001 8

Proteins exhibit a variety of dense phases ranging from gels, aggregates, and precipitates to crystalline phases and dense liquids. Although the structure of the crystalline phase is known in atomistic detail, little attention has been paid to noncrystalline protein dense phases, and in many cases the structures of these phases are assumed to be fully amorphous. In this work, we used small-angle neutron scattering, electron microscopy, and electron tomography to measure the structure of ovalbumi ...[more]

PMID: 26488663

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