Bovine beta-lactoglobulin acts as an acid-resistant drug carrier by exploiting its diverse binding regions.
Binding of fluorine-containing drugs to bovine beta-lactoglobulin, the most abundant whey protein in bovine milk, was investigated by means of (19)F NMR and mass spectrometry. The stoichiometry of the binding and its stability in acidic medium, where beta-lactoglobulin is folded and stable, were also studied, along with competition from molecules that can be regarded as analogs of physiological ligands to bovine beta-lactoglobulin. Conditional binding data were combined with protein structural information derived from circular dichroism and limited proteolysis studies. Spectroscopic techniques were also used to assess whether the bound drugs stabilize the protein structure against denaturation by chaotropes or temperature at various pH values. The results obtained provide evidence for the presence of multiple binding regions on the protein, with a specific and different affinity for structurally different classes of hydrophobic drugs and, more generally, that bovine beta-lactoglobulin can bind and protect against low pH values various classes of drugs of pharmaceutical relevance.
Barbiroli
Alberto
A
Dipartimento di Scienze Molecolari Agroalimentari, Università degli Studi di Milano, Via Celoria 2, I-20133 Milano, Italy.
Beringhelli
Tiziana
T
Bonomi
Francesco
F
Donghi
Daniela
D
Ferranti
Pasquale
P
Galliano
Monica
M
Iametti
Stefania
S
Maggioni
Daniela
D
Rasmussen
Patrizia
P
Scanu
Sandra
S
Vilardo
Maria Caterina
MC
D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism*; D005461:Fluorine; D005480:Flurbiprofen / Q000378:metabolism; D000077340:Fluvastatin; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000378:metabolism*; D007782:Lactoglobulins / Q000378:metabolism*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding
D002352:Carrier Proteins; D005229:Fatty Acids, Monounsaturated; D007211:Indoles; D007782:Lactoglobulins; D005461:Fluorine; D000077340:Fluvastatin; D005480:Flurbiprofen