Comparative analysis of human γD-crystallin aggregation under physiological and low pH conditions
| Autor: | Chien-Ting Li, Mei-Er Chen, Chih-Kai Chang, Steven S.-S. Wang, Josephine W. Wu, Hwai-Shen Liu, Chun-Hsien Lo, Wen-Sing Wen, Wei-An Chen |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Protein Denaturation
Protein Structure Protein Folding Circular dichroism Light Molecular Sequence Data lcsh:Medicine Molecular Dynamics Simulation Biology Bioinformatics Biochemistry Anilino Naphthalenesulfonates Protein Structure Secondary Fluorescence spectroscopy chemistry.chemical_compound Protein structure Nephelometry and Turbidimetry Crystallin Macromolecular Structure Analysis Humans Protein Interaction Domains and Motifs Amino Acid Sequence gamma-Crystallins Spectroscopy lcsh:Science Molecular Biology Protein secondary structure Multidisciplinary lcsh:R Temperature Biology and Life Sciences Proteins Fibrillogenesis Hydrogen-Ion Concentration Recombinant Proteins eye diseases Protein Structure Tertiary Protein Misfolding chemistry Biophysics Thioflavin lcsh:Q sense organs Research Article |
| Zdroj: | PLoS ONE, Vol 9, Iss 11, p e112309 (2014) PLoS ONE |
| ISSN: | 1932-6203 |
| Popis: | Cataract, a major cause of visual impairment worldwide, is the opacification of the eye’s crystalline lens due to aggregation of the crystallin proteins. The research reported here is aimed at investigating the aggregating behavior of γ-crystallin proteins in various incubation conditions. Thioflavin T binding assay, circular dichroism spectroscopy, 1-anilinonaphthalene-8-sulfonic acid fluorescence spectroscopy, intrinsic (tryptophan) fluorescence spectroscopy, light scattering, and electron microscopy were used for structural characterization. Molecular dynamics simulations and bioinformatics prediction were performed to gain insights into the γD-crystallin mechanisms of fibrillogenesis. We first demonstrated that, except at pH 7.0 and 37°C, the aggregation of γD-crystallin was observed to be augmented upon incubation, as revealed by turbidity measurements. Next, the types of aggregates (fibrillar or non-fibrillar aggregates) formed under different incubation conditions were identified. We found that, while a variety of non-fibrillar, granular species were detected in the sample incubated under pH 7.0, the fibrillogenesis of human γD-crystallin could be induced by acidic pH (pH 2.0). In addition, circular dichroism spectroscopy, 1-anilinonaphthalene-8-sulfonic acid fluorescence spectroscopy, and intrinsic fluorescence spectroscopy were used to characterize the structural and conformational features in different incubation conditions. Our results suggested that incubation under acidic condition led to a considerable change in the secondary structure and an enhancement in solvent-exposure of the hydrophobic regions of human γD-crystallin. Finally, molecular dynamics simulations and bioinformatics prediction were performed to better explain the differences between the structures and/or conformations of the human γD-crystallin samples and to reveal potential key protein region involved in the varied aggregation behavior. Bioinformatics analyses revealed that the initiation of amyloid formation of human γD-crystallin may be associated with a region within the C-terminal domain. We believe the results from this research may contribute to a better understanding of the possible mechanisms underlying the pathogenesis of senile nuclear cataract. |
| Databáze: | OpenAIRE |
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