根拠: The protein appears as monomer during size exclusion chromatography. Removal of the Ig-like domain in which the b-strand swap occurs has no effect on activity. The protein is possibly ...根拠: The protein appears as monomer during size exclusion chromatography. Removal of the Ig-like domain in which the b-strand swap occurs has no effect on activity. The protein is possibly attached to the cell surface in vivo and might dimerize under these condition.