| Using O PFP and O TFA carrying glycosyl halides , trisaccharide ( Manalpha 1 > 2Manalpha1 > 2Man ) and tetrasaccharide ( Glcalpha 1 > 3Manalpha1 > 2Manalpha1 > 2Man ) portions of monoglucosylated high mannose type dodecasaccharide ( Glc ( 1 ) Man ( 9 ) GlcNAc ( 2 ) ) , a putative ligand for the ER chaperon , calnexin and calreticulin , were synthesized . . ^^^ |