A calorimetric and structural analysis of cooperativity in the thermal unfolding of the PDZ tandem of human Syntenin-1.
Int J Biol Macromol
; 242(Pt 1): 124662, 2023 Jul 01.
Article
em En
| MEDLINE
| ID: mdl-37119899
ABSTRACT
Syntenin-1 is a multidomain protein containing a central tandem of two PDZ domains flanked by two unnamed domains. Previous structural and biophysical studies show that the two PDZ domains are functional both isolated and in tandem, occurring a gain in their respective binding affinities when joined through its natural short linker. To get insight into the molecular and energetic reasons of such a gain, here, the first thermodynamic characterization of the conformational equilibrium of Syntenin-1 is presented, with special focus on its PDZ domains. These studies include the thermal unfolding of the whole protein, the PDZ-tandem construct and the two isolated PDZ domains using circular dichroism, differential scanning fluorimetry and differential scanning calorimetry. The isolated PDZ domains show low stability (ΔG < 10 kJ·mol-1) and poor cooperativity compared to the PDZ-tandem, which shows higher stability (20-30 kJ·mol-1) and a fully cooperative behaviour, with energetics similar to that previously described for archetypical PDZ domains. The high-resolution structures suggest that this remarkable increase in cooperativity is associated to strong, water-mediated, interactions at the interface between the PDZ domains, associated to nine conserved hydration regions. The low Tm value (45 °C), the anomalously high unfolding enthalpy (>400 kJ·mol-1), and native heat capacity values (above 40 kJ·K-1·mol-1), indicate that these interfacial buried waters play a relevant role in Syntenin-1 folding energetics.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Dobramento de Proteína
/
Sinteninas
Limite:
Humans
Idioma:
En
Revista:
Int J Biol Macromol
Ano de publicação:
2023
Tipo de documento:
Article