Solubilization of the chemokine receptor CXCR4

The chemokine receptor CXCR4 was solubilized from the human T-cell line CEM by using the detergent n-dodecyl-beta-maltoside (DDM) and cholesteryl hemi succinate ester (CHS). Binding studies with I-125-SDF-1 alpha revealed a di ssociation constant of 5.33 nM and a receptor density (B-max) of 2.68 pmol/ mg in CEM membranes at 4 degrees C. The affinity of solubilized CXCR4 for S DF-1 alpha was identical to membrane-bound CXCR4. Binding of gp120 to solub ilized CXCR4 was demonstrated by coprecipitation of gp120 with anti-CXCR4 a ntibodies. (C) 2000 Academic Press.