Novel GPI structures of the membrane anchor of acetylcholinesterase from the electric organ of Torpedo californica

ABSTRACT

The structure of the glycan moiety of the glycosylphosphatidylinositol (GPI) membrane anchor from Torpedo californica electric organ acetylcholinesterase was solved using nuclear magnetic resonance (NMR), methylation analysis, and chemical and enzymic microsequencing. Two structures were found to be present Glcalfa1-2 Manalfa1-2 Manalfa1-6 Manalfa1-4 GlcNalfa1-6myo-inositol, and Glcalfa1-2 Manalfa1-2 Manalfa1-6 (GalNAcß1-4) Manalfa1-4 GlcNalfa1-6myo-inositol. The presence of glucose in this GPI anchor structure is a novel feature. The anchor was also shown to contain 2.3 residues of ethanolamine per molecule