Structure of Carbohydrates Present in Glycoproteins from Scedosporium prolificans
Wagner, R.1; Sassaki, G. 1; Pinto, M.R. 2, 3; Danelon, M.C. 2; Barreto-Bergter, E. 2; Gorin, P.A.J. 1
1 Departamento de Bioquímica, UFPR, Curitiba, PR, 81531-990; 2 Instituto de Microbiologia, UFRJ, Rio de Janeiro, RJ, 21944-970; 3 Departamento de Microbiologia, ICB,USP, São Paulo, SP, 05508-000.
e-mail: cesarat@ufpr.br
A rhamnomannoprotein (RPM-Sp) with 35% protein was isolated from mycelia of the pathogen Scedosporium prolificans. It was analyzed using a combination of techniques including TLC, hydrolysis-GC-MS, methylation-GC-MS, ESI-MS, and NMR, both mono- and bidimensional. RPM-Sp contained antennae with mainly rhamnose and mannose, present as nonreducing end-, 2-O-, and 3-O-subst. Rhap, and nonreducing end-, 2-O- and 3-O-subst. Manp units. All monosaccharide units had the a-glycosidic configuration. Their distribution was shown by products formed on partial acetolysis, namely a-Manp-(1®2)-Man, a-Manp-(1®2)-a-Manp-(1®2)-Man, a-Manp-(1®3)-Man, a-Rhap-(1®2)-Man, a-Rhap-(1®2)-Rha, and a-Rhap-(1®2)-a-Rhap-(1®2)-Rha. Partial hydrolysis of RPM-Sc gave a non-dialyzable product with (1®2)-linked a-Manp groups linked to protein, probably via a glucosamine bridge. A smaller proportion of O-linked mono- and oligosaccharide groups were also attached to protein, as shown by reductive, alkaline b-elimination (TLC). Membrane filtration of PRM-Sc gave rise to 16.5 and 72.0 KDa components, the latter being richer in rhamnose. The C-1 region of their 13C NMR spectra contained similar signals, although a minor one at d 103.2 was greater in the spectrum of the 72.0 KDa fraction, but could not be assigned. These structures differed from those present in the RPM of Pseudallescheria boydii, a related pathogen, which contained a higher proportion of (1®3)- and apparently no (1®2)-linked a-Rhap units (M.R. Pinto et al., 2001, 2005).
Supported by CNPq, FAPERJ, FAPESP, PRONEX-1996 and Fundação Araucária
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