Thermodynamic analysis of hydration in human serum heme-albumin
- Invento S.r.l., 'Companies Incubator' of the University of Torino, Via Nizza 52, I-10126, Torino (Italy)
- Department of Structural and Functional Biology, and Center of Neurosciences, University of Insubria, Via Alberto da Giussano 12, I-21052 Busto Arsizio (Italy)
- Department of Chemistry I.F.M. and Center of Molecular Imaging (CIM), University of Torino, Via Nizza 52, I-10126 Torino (Italy)
- Department of Biology and Interdepartmental Laboratory for Electron Microscopy, Viale Guglielmo Marconi 446, University 'Roma Tre', I-00146 Roma (Italy)
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 {sup o}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 = {sup 5}/{sub 2} manifold. Values of correlation times for tensor fluctuation ({tau}{sub v}) and chemical exchange of water molecules ({tau}{sub M}) show the expected temperature dependence, with activation enthalpies of -1.94 and -2.46 {+-} 0.2 kJ mol{sup -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 {Delta}H = 68 {+-} 28 kJ mol{sup -1} and {Delta}S = 200 {+-} 80 J mol{sup -1} K{sup -1}. These results highlight the role of the water solvent in heme-HSA structure-function relationships.
- OSTI ID:
- 22199753
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 385, Issue 3; Other Information: Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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