The 5-O-beta-D-galactofuranosyl-containing peptidophosphogalactomannan of Penicillium charlesii. Characterization of the mannan by 13C NMR spectroscopy.
Penicillium charlesii secretes a galactofuranosyl and phosphodiester-containing peptidophosphogalactomannan (pPGM). A linear mannan was prepared from pPGM by treatment with 48% aqueous HF which selectively cleaves galactofuranosyl and phosphodiesters; treatment with alkaline borohydride releases the mannan from the polypeptide. Mannan from P. charlesii cultured in D-[1,2-13C2]glucose contained mannopyranosyl residues which were enriched in 13C at both C-1 and C-2 and, to a lesser extent, at C-5 and C-6. The mannan was examined with a combination of 13C NMR INADEQUATE pulse sequence and selective 13C saturation to assign the resonance frequency of anomeric carbons directly coupled to specific C-2 signals. Three species of mannosyl residues, each substituted with a glycosidic linkage at C-2, and a fourth species substituted at C-6 and not substituted at C-2 were observed. Mannan obtained from P. charlesii cultured in D-[6-13C]glucose contained mannopyranosyl residues which were enriched in 13C primarily in C-6. The mannan was examined by DEPT 13C NMR to determine the number of species which were substituted at C-6. Mannan, treated as described above, contained a 1----6-linked mannopyranosyl species. pPGM contains minor quantities of at least four other substances attached to hydroxymethyl groups of the hexosyl residues.
Unkefer
C J
CJ
Isotope and Structural Chemistry Group, Los Alamos National Laboratory, New Mexico 87545.
Gander
J E
JE
D002240:Carbohydrate Sequence; D005690:Galactose / Q000031:analogs & derivatives*; D006025:Glycosaminoglycans / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000032:analysis*; D008969:Molecular Sequence Data; D010407:Penicillium / Q000378:metabolism*
D006025:Glycosaminoglycans; D008351:Mannans; C012990:galactomannan; D005690:Galactose