NMR assignment of the galactomannan of Candida lipolytica

The chemical structure of the cell wall galactomannan of Candida lipolytica was analyzed using two-dimensional NMR techniques without chemical fragmentation. The H-1-H-2-correlated cross-peaks of the galactomannan indicated that it consists of an alpha-1,6-linked mannan backbone moiety with side chains, A sequential NMR assignment of the side chains through nuclear Overhauser effect (NOE) cross-peaks indicated that the triose side chain contains an alpha-1,2-linked galactopyranose unit at the non-reducing terminal, The structure was significantly different from the galactomannan of Trichophyton. The molar ratio of the side chains calculated from the W-I signal dimensions indicated that ca, 45% of the backbone alpha-1,6-linked! mannose units are not substituted with side chains and are responsible for the reactivity of the galactomannan with factor 9 serum. (C) 1997 Federation of European Biochemical Societies.