Energy Transfer Studies between Trp Residues of Three Lipocalin Proteins Family, α1-Acid Glycoprotein, (Orosomucoid), β-Lactoglobulin and Porcine Odorant Binding Protein and the Fluorescent Probe, 1-Aminoanthracene (1-AMA)

Abstract

Energy transfer studies between Trp residues of α(1)-acid glycoprotein, β-lactoglobulin and porcine odorant binding protein (OBP) and the fluorescent probe 1-aminoanthracene (1-AMA) were performed. 1-AMA binds to the hydrophobic binding sites of the three proteins inducing a decrease in the fluorescence intensity of the Trp residues accompanied by an increase of that of 1-AMA. Our results indicate that 1-AMA is in close contact with hydrophobic tryptophan residue of β-lactoglobulin (Trp 19) to the difference of its binding to OBP, where Trp residues are far from the pocket and to α(1)-acid glycoprotein where three Trp residues are present at different areas of the protein.

Biotechnological applications of mammalian odorant-binding proteins

“…This method, is simple, fast, and only requires a small amount of protein and no separation step is needed, avoiding though the error measurements related to this last step [61]. Several fluorescent ligands are actually used to measure the OBP-mediated binding: 6-ptoluidinylnaphthalene-2sulfonate (TNS), 2-isobutyl-3-methoxypyrazine (IBMP), N-phenyl-1-naphthylamine (1-NPN), fluorescein and 1-aminoanthracene (1-AMA) [29,62]. The 1-AMA was used for the first time to measure the activity of pig OBP (OBP-I) [52] being actually widely applied to study the interactions of the lipocalin superfamily proteins (Table S1).…”