Taxonomic group: algae / Chlorophyta
(Phylum: Chlorophyta)
NCBI PubMed ID: 6692821Journal NLM ID: 0107600Publisher: Oxford, UK: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
Institutions: Institute of Biochemistry, Köln
Crude membrane fractions from Volvox carteri in the presence of detergent and metal complexing agent catalyze the transfer of glucose from dolichyl phosphate glucose to branched dolichyl diphosphate chitobiosyl pentamannoside Dol-PP-(GlcNAc)2-(Man)5, a known intermediate of the lipid-mediated pathway of N-glycosylation of proteins, resulting in the formation of Dol-PP-(GlcNAc)2-(Man)5-(Glc)1. Under the various conditions tested, neither Dol-P-Man nor other known mannosyl donors of the nucleoside-activated or lipid-activated type can serve as donor molecules for the elongation of the lipid-linked heptasaccharide. On the other hand, calf liver microsomes in similar experiments mannosylated the heptasaccharide further with Dol-P-Man up to a nonamannoside, Dol-PP-(GlcNAc)2-(Man)9. A direct glucosylation of the acceptor, however, with Dol-P-Glc failed in this system. The (GlcNAc)2-(Man)5-(Glc)1, obtained after mild acid hydrolysis of the above glycolipid is not significantly split by an unspecific α-glucosidase from yeast. However, Volvox microsomes liberated most of the glucose indicating a specific glucosidase in the membranes of the alga. This enzyme does not act on (GlcNAc)2-(Man)9-(Glc)1, the usual protein-linked carbohydrate intermediate of trimming processes of N-glycosidic glycoproteins. The data on glycolipid formation let us postulate that in Volvox the normal N-glycosylation pathway differs from that found in higher plants and animals either by a lack of evolution or by mutation in the genes coding for the mannosyl transferases involved.
Structure type: oligomer
Compound class: N-glycan
Contained glycoepitopes: IEDB_123886,IEDB_130701,IEDB_135813,IEDB_136104,IEDB_137340,IEDB_137485,IEDB_140116,IEDB_141793,IEDB_141807,IEDB_141830,IEDB_143632,IEDB_144983,IEDB_150077,IEDB_151531,IEDB_152206,IEDB_540671,IEDB_548907,IEDB_983930,SB_136,SB_196,SB_197,SB_198,SB_33,SB_44,SB_67,SB_72,SB_73,SB_74,SB_85
Methods: gel filtration, TLC, enzymatic digestion, radiolabeled synthesis, oligosaccharide glucosidase assay
NCBI Taxonomy refs (TaxIDs): 3068Reference(s) to other database(s): CCSD:
5868, CBank-STR:17550
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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