Human serum albumin (HSA) participates in heme scavenging, the bound heme turning out to be a reactivity center and a powerful spectroscopic probe. Here, the reversible unfolding of heme-HSA has been investigated by H-1-NMR relaxometry, circular dichroism, and absorption spectroscopy. In the presence of 6 equiv of myristate ( thus fully saturating all available fatty acid binding sites in serum heme-albumin), 1.0 M guanidinium chloride induces some unfolding of heme-HSA, leading to the formation of a folding intermediate; this species is characterized by increased relaxivity and enhanced dichroism signal in the Soret region, suggesting a more compact heme pocket conformation. Heme binds to the folding intermediate with K-d = (1.2 +/- 0.1) x 10(-6) M. In the absence of myristate, the conformation of the folding intermediate state is destabilized and heme binding is weakened [K-d = (3.4 +/- 0.1) x 10(-5) M]. Further addition of guanidinium chloride ( up to 5 M) brings about the usual denaturation process. In conclusion, myristate protects HSA from unfolding, stabilizing a folding intermediate state in equilibrium with the native and the fully unfolded protein, envisaging a two-step unfolding pathway for heme-HSA in the presence of myristate.
Fanali G., D.S.G. (2009). Reversible two-step unfolding of heme-human serum albumin: A 1H-NMR relaxometric and circular dichroism study. JBIC, 14(2), 209-217.
Tipologia: | Articolo su rivista |
Citazione: | Fanali G., D.S.G. (2009). Reversible two-step unfolding of heme-human serum albumin: A 1H-NMR relaxometric and circular dichroism study. JBIC, 14(2), 209-217. |
Lingua: | English |
Settore Scientifico Disciplinare: | Settore BIO/10 |
Revisione (peer review): | Sì, ma tipo non specificato |
Tipo: | Articolo |
Rilevanza: | Rilevanza internazionale |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1007/s00775-008-0439-7 |
Stato di pubblicazione: | Pubblicato |
Data di pubblicazione: | 2009 |
Titolo: | Reversible two-step unfolding of heme-human serum albumin: A 1H-NMR relaxometric and circular dichroism study |
Autori: | |
Autori: | Fanali G., De Sanctis G., Gioia M., Coletta M., Ascenzi P., Fasano M. |
Appare nelle tipologie: | 01 - Articolo su rivista |
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