Affinity studies of beta-2-glycoprotein I using capillary electrophoresis

• Beta2-glycoprotein I (b2gpI), also known as apolipoprotein H, is a plasma protein which is involved in the blood coagulation cascade. It binds negatively charged substances such as heparin, DNA, and anionic phospholipids. A number of functions of b2gpI have been proposed, however, the precise function is still not entirely known. Circulating autoantibodies against b2gpI are associated with increased risk of thrombotic events, such as thrombosis and reoccurring fetal loss. It is therefore of interest to functionally characterize b2gpI including the influence of anti-b2gpI autoantibodies on the ligand binding behavior of the protein. The characterization of interactions between biological molecules may be accomplished by capillary electrophoresis under non-denaturing conditions, without the need for immobilization. To avoid charge dependent analyte adsorption to the negative charges of the capillary wall we found the pH hysteresis effect of silica very useful. An acidic pretreatment of the capillary made it possible to perform a subsequent analysis at neutral pH. We were able to perform binding studies between b2gpI and heparin and monosaccharides at different ionic strengths and temperatures in a simple way. We could also study the effect of mildly denaturing conditions on the binding to the different ligands simply by adding sodium dodecyl sulfate (SDS), urea and ACN to the background electrolyte. The approach is simple, fast and automatic. The ionic strength, temperature and other parameters such as denaturing agents could easily be changed to characterize the binding between b2gpI and different ligands.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Chemistry

Kemi

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