Study of the pH-dependent conformational changes in alpha1-acid glycoprotein using FRET

We studied pH-dependent conformational changes in alpha1-acid glycoprotein using both binding of cationic fluorescent probe Quinaldine Red with protein molecule and changes in distance between tryptophan from binding site of the protein and Calcofluor White on glycan surface using FRET. Our data show that the binding site of the protein has undergone a conformational change at pH 9.0. At this pH. the binding site forms a more hydrophobic region and tryptophan residues from the binding site move to the center of the protein core.