Equilibrium unfolding of the PDZ domain of β2-syntrophin
β2-syntrophin, a dystrophin-associated protein, plays a pivotal role in insulin secretion by pancreatic β-cells. It contains a PDZ domain (β2S-PDZ) that, in complex with protein-tyrosine phosphatase ICA512, anchors the dense insulin granules to actin filaments. The phosphorylation state of β2-syntro...
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| Autores principales: | , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
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2012
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/87841 |
| Aporte de: |
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I19-R120-10915-87841 |
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dspace |
| institution |
Universidad Nacional de La Plata |
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I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Exactas β2-syntrophin PDZ domain |
| spellingShingle |
Ciencias Exactas β2-syntrophin PDZ domain Torchio, Gabriela María Ermácora, Mario Roberto Sica, Mauricio Pablo Equilibrium unfolding of the PDZ domain of β2-syntrophin |
| topic_facet |
Ciencias Exactas β2-syntrophin PDZ domain |
| description |
β2-syntrophin, a dystrophin-associated protein, plays a pivotal role in insulin secretion by pancreatic β-cells. It contains a PDZ domain (β2S-PDZ) that, in complex with protein-tyrosine phosphatase ICA512, anchors the dense insulin granules to actin filaments. The phosphorylation state of β2-syntrophin allosterically regulates the affinity of β2S-PDZ for ICA512, and the disruption of the complex triggers the mobilization of the insulin granule stores. Here, we investigate the thermal unfolding of β2S-PDZ at different pH and urea concentrations. Our results indicate that, unlike other PDZ domains, β2S-PDZ is marginally stable. Thermal denaturation experiments show broad transitions and cold denaturation, and a two-state model fit reveals a significant unfolded fraction under physiological conditions. Furthermore, T<sub>m</sub> and T<sub>max</sub> denaturant-dependent shifts and noncoincidence of melting curves monitored at different wavelengths suggest that two-state and three-state models fail to explain the equilibrium data properly and are in better agreement with a downhill scenario. Its higher stability at pH > 9 and the results of molecular dynamics simulations indicate that this behavior of β2S-PDZ might be related to its charge distribution. All together, our results suggest a link between the conformational plasticity of the native ensemble of this PDZ domain and the regulation of insulin secretion. |
| format |
Articulo Articulo |
| author |
Torchio, Gabriela María Ermácora, Mario Roberto Sica, Mauricio Pablo |
| author_facet |
Torchio, Gabriela María Ermácora, Mario Roberto Sica, Mauricio Pablo |
| author_sort |
Torchio, Gabriela María |
| title |
Equilibrium unfolding of the PDZ domain of β2-syntrophin |
| title_short |
Equilibrium unfolding of the PDZ domain of β2-syntrophin |
| title_full |
Equilibrium unfolding of the PDZ domain of β2-syntrophin |
| title_fullStr |
Equilibrium unfolding of the PDZ domain of β2-syntrophin |
| title_full_unstemmed |
Equilibrium unfolding of the PDZ domain of β2-syntrophin |
| title_sort |
equilibrium unfolding of the pdz domain of β2-syntrophin |
| publishDate |
2012 |
| url |
http://sedici.unlp.edu.ar/handle/10915/87841 |
| work_keys_str_mv |
AT torchiogabrielamaria equilibriumunfoldingofthepdzdomainofb2syntrophin AT ermacoramarioroberto equilibriumunfoldingofthepdzdomainofb2syntrophin AT sicamauriciopablo equilibriumunfoldingofthepdzdomainofb2syntrophin |
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Repositorios |
| _version_ |
1764820489434300418 |