Hydrophobic labelling of membrane-embedded proteins with lipophilic reagents. Incorporation of [125I]INA and [125I]TID into B lymphocyte membrane immunoglobulins.
Hydrophobic labelling is frequently used in the study of membrane-inserted domains of intrinsic proteins. However, the published procedures, fail to incorporate sufficient radioactivity into membrane immunoglobulins of B lymphocytes to permit investigation of their subunit structures and associations with other proteins. In order to increase the specific radioactivity of [125I]iodonaphthylazide ([125I]INA), an improved method for the synthesis of the reagent was developed. In addition, the optimal conditions for labelling B lymphocytes with [125I]INA and the commercially available reagent 3-(trifluoromethyl)-3-(3'-[125I]iodophenyl)diazirine ([125I]TID) were elaborated. Under these optimized conditions, Ig molecules labelled with [125I]INA and [125I]TID were isolated and analysed in detail by SDS-PAGE. The usefulness of the two reagents for the investigation of lipid-embedded domains of membrane proteins is discussed.
Institut für Experimentelle Immunologie, Universität Marburg, F.R.G.
L
L
Vogel
A
A
Hildebrand
T
T
Tschammer
D
D
Haustein
D000818:Animals; D001386:Azides / Q000138:chemical synthesis; D001389:Azirines; D001402:B-Lymphocytes / Q000032:analysis; D007457:Iodine Radioisotopes; D008563:Membrane Lipids; D008565:Membrane Proteins / Q000032:analysis*; D051379:Mice; D008970:Molecular Weight; D011947:Receptors, Antigen, B-Cell / Q000032:analysis*; D012995:Solubility
D001386:Azides; D001389:Azirines; D007457:Iodine Radioisotopes; D008563:Membrane Lipids; D008565:Membrane Proteins; D011947:Receptors, Antigen, B-Cell; C015298:iodonaphthylazide; C033174:3-(trifluoromethyl)-3-(3-iodophenyl)diazirine