The fifth domain of beta 2-glycoprotein I contains a phospholipid binding site (Cys281-Cys288) and a region recognized by anticardiolipin antibodies.

摘要: We have identified a phospholipid binding site in the fifth domain of beta 2-glycoprotein I (beta 2-GPI). Using synthetic peptides spanning 2-GPI, we shown that presence sequence Glu274-Cys288 caused decrease purified anticardiolipin (aCL) antibodies modified cardiolipin (CL)-ELISA by inhibiting 2-GPI to CL. This peptide bound and could be eluted from CL affinity column manner similar native 2-GPI. Peptides corresponding other regions had no inhibitory effect. The activity was restricted Cys281-Lys-Asn-Lys-Glu-Lys-Lys-Cys288. which two flanking cysteine residues were deleted or substituted with serine possessed activity, indicating conformation this highly positively charged may critical for binding. aCL patients autoimmune disease bind directly wells coated but not preparation cleaved between Lys317 Thr318. integrity is therefore these recognize putative epitope most likely region.