Thermodynamic analysis of hydration in human serum heme-albumin.
Biochem Biophys Res Commun
; 385(3): 385-9, 2009 Jul 31.
Article
en En
| MEDLINE
| ID: mdl-19464261
ABSTRACT
Ferric human serum heme-albumin (heme-HSA) shows a peculiar nuclear magnetic relaxation dispersion (NMRD) behavior that allows to investigate structural and functional properties. Here, we report a thermodynamic analysis of NMRD profiles of heme-HSA between 20 and 60 degrees C to characterize its hydration. NMRD profiles, all showing two Lorentzian dispersions at 0.3 and 60 MHz, were analyzed in terms of modulation of the zero field splitting tensor for the S=5/2 manifold. Values of correlation times for tensor fluctuation (tau(v)) and chemical exchange of water molecules (tau(M)) show the expected temperature dependence, with activation enthalpies of -1.94 and -2.46+/-0.2 kJ mol(-1), respectively. The cluster of water molecules located in the close proximity of the heme is progressively reduced in size by increasing the temperature, with DeltaH=68+/-28 kJ mol(-1) and DeltaS=200+/-80 J mol(-1) K(-1). These results highlight the role of the water solvent in heme-HSA structure-function relationships.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Termodinámica
/
Albúmina Sérica
/
Agua
/
Hemo
Límite:
Humans
Idioma:
En
Revista:
Biochem Biophys Res Commun
Año:
2009
Tipo del documento:
Article
País de afiliación:
Italia