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Modulation of heme and myristate binding to human serum albumin by anti‐HIV drugs
Author(s) -
Fanali Gabriella,
Bocedi Alessio,
Ascenzi Paolo,
Fasano Mauro
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.05978.x
Subject(s) - human serum albumin , chemistry , allosteric regulation , nevirapine , heme , abacavir , dissociation constant , binding site , serum albumin , biochemistry , stereochemistry , human immunodeficiency virus (hiv) , virology , biology , receptor , virus , hepatitis b virus , enzyme , viral load , lamivudine , antiretroviral therapy
Human serum albumin (HSA) has an extraordinary ligand‐binding capacity, and transports Fe(III)heme and medium‐ and long‐chain fatty acids. In human immunodeficiency virus‐infected patients the administered drugs bind to HSA and act as allosteric effectors. Here, the binding of Fe(III)heme to HSA in the presence of three representative anti‐HIV drugs and myristate is investigated. Values of the dissociation equilibrium constant K d for Fe(III)heme binding to HSA were determined at different myristate concentrations, in the absence and presence of anti‐HIV drugs. Nuclear magnetic relaxation dispersion profiles of HSA–Fe(III)heme were measured, at different myristate concentrations, in the absence and presence of anti‐HIV drugs. Structural bases for anti‐HIV drug binding to HSA are provided by automatic docking simulation. Abacavir and nevirapine bind to HSA with K d values of 1 × 10 −6 and 2 × 10 −6 m , respectively. Therefore, at concentrations used in therapy (in the 1–5 × 10 −6 m range) abacavir and nevirapine bind to HSA and increase the affinity of heme for HSA. In the presence of abacavir or nevirapine, the affinity is not lowered by myristate. FA7 should therefore be intended as a secondary binding site for abacavir and nevirapine. Binding of atazanavir is limited by the large size of the drug, although preferential binding may be envisaged to a site positively coupled with FA1 and FA2, and negatively coupled to FA7 . As a whole, these results provide a foundation for the comprehension of the complex network of links modulating HSA‐binding properties.