A new pullulan and a branched (1-->3)-, (1-->6)-linked beta-glucan from the lichenised ascomycete Teloschistes flavicans.
The polysaccharides formed on hot alkaline extraction of the ascomycetous lichen Teloschistes flavicans were fractionated to give two glucans, which were characterised by methylation analysis and 1D and 2D NMR spectroscopy. One was a branched beta-glucan containing (1-->3) and (1-->6) linkages, a structure which is more typical of basidiomycetes rather than ascomycetes, which have linear glucans. The other was an alpha-glucan with alternating (1-->4) and (1-->6) linkages, found for the first time in Nature. This structure can be classified as a pullulan, which has been isolated from the fungi Aureobasidium pullulans, Tremella mesenterica, and Cyttaria harioti, but has different ratios of the component glycosidic linkages. The significance of the presence of the isolated alpha- and beta-glucans is discussed.
Reis
Rodrigo A
RA
Departamento de Bioquímica, Universidade Federal do Paraná, C.P. 19046, 81531-990, Curitiba, Brazil.
Tischer
Cesar A
CA
Gorin
Philip A J
PA
Iacomini
Marcello
M
D001203:Ascomycota / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005936:Glucans / Q000737:chemistry* / Q000302:isolation & purification; D005947:Glucose; D008011:Lichens / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data
D005936:Glucans; C033671:epiglucan; D005947:Glucose