The 5-O-beta-D-galactofuranosyl-containing glycopeptide from Penicillium charlesii. Identification of phosphocholine attached to C-6 of mannopyranosyl residues of the mannan region

Abstract

Peptidophosphogalactomannan from Penicillium charlesii contains ethanolamine, presumably linked via phosphodiester to galactomannan (Rick, P. D., Drewes, L. R., and Gander, J. E., (1974) J. Biol. Chem. 249, 2072-2078). These investigations have been extended using 13C and 31P NMR spectroscopy to show that peptidophosphogalactomannan also contains choline and that both ethanolamine and choline are linked through phosphodiester linkages to C-8 of mannosyl residues of the mannan region of peptidophosphogalactomannan. Approximately one-half of the bases derived from ethanolamine, and which are attached to the mannan as phosphodiesters, are released as choline upon treatment with dilute alkali. It was shown that 13C from L-[methyl-13C]methionine is incorporated into methyl groups of mannosyl-6-phosphocholine in vivo. There were no 13C NMR signals from the methyl carbons of either 2-methylaminoethanol (33.3 ppm) or 2-dimethylaminoethanol (45.9 ppm) observed in these experiments even though the major signal was from the methyl carbons of choline (56.9 ppm).