Abstract | BACKGROUND: METHODOLOGY/PRINCIPAL FINDINGS: In this study we examined whether three type III HLP predisposing apoE3 variants, namely R136S, R145C and K146E affect the biophysical properties of the protein. Circular dichroism (CD) spectroscopy revealed that these mutations do not significantly alter the secondary structure of the protein. Thermal and chemical unfolding analysis revealed small thermodynamic alterations in each variant compared to wild-type apoE3, as well as effects in the reversibility of the unfolding transition. All variants were able to remodel multillamelar 1,2-Dimyristoyl-sn-glycero-3-phosphocholine ( DMPC) vesicles, but R136S and R145C had reduced kinetics. Dynamic light scattering analysis indicated that the variant R136S exists in a higher-order oligomerization state in solution. Finally, 1-anilinonaphthalene-8-sulfonic acid (ANS) binding suggested that the variant R145C exposes a larger amount of hydrophobic surface to the solvent. CONCLUSIONS/SIGNIFICANCE: Overall, our findings suggest that single amino acid changes in the functionally important region 136-150 of apoE3 can affect the molecule's stability and conformation in solution and may underlie functional consequences. However, the magnitude and the non-concerted nature of these changes, make it unlikely that they constitute a distinct unifying mechanism leading to type III HLP pathogenesis.
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Authors | Dimitra Georgiadou, Angeliki Chroni, Alexander Vezeridis, Vassilis I Zannis, Efstratios Stratikos |
Journal | PloS one
(PLoS One)
Vol. 6
Issue 11
Pg. e27037
( 2011)
ISSN: 1932-6203 [Electronic] United States |
PMID | 22069485
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- Anilino Naphthalenesulfonates
- Apolipoprotein E3
- Fluorescent Dyes
- Receptors, LDL
- Recombinant Proteins
- 1-anilino-8-naphthalenesulfonate
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Topics |
- Anilino Naphthalenesulfonates
(pharmacology)
- Apolipoprotein E3
(chemistry, genetics, metabolism)
- Astrocytoma
(genetics, metabolism, pathology)
- Biophysics
- Circular Dichroism
- Fluorescent Dyes
(pharmacology)
- Genetic Variation
- Humans
- Hyperlipoproteinemia Type III
(genetics, pathology)
- Kinetics
- Mutagenesis, Site-Directed
- Mutation
(genetics)
- Protein Binding
- Protein Conformation
- Protein Structure, Secondary
- Receptors, LDL
(metabolism)
- Recombinant Proteins
(genetics, metabolism)
- Tumor Cells, Cultured
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