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Identification of methylated GnTI‐dependent N ‐glycans in Botryococcus brauni
Author(s) -
Schulze Stefan,
Urzica Eugen,
Reijnders Maarten J. M. F.,
Geest Henri,
Warris Sven,
Bakker Linda V.,
Fufezan Christian,
Martins dos Santos Vitor A. P.,
Schaap Peter J.,
Peters Sander A.,
Hippler Michael
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14713
Subject(s) - botryococcus braunii , glycan , biochemistry , glycosylation , glycoprotein , biology , n linked glycosylation , chemistry , botany , algae
Summary In contrast to mammals and vascular plants, microalgae show a high diversity in the N ‐glycan structures of complex N ‐glycoproteins. Although homologues for β1,2‐ N ‐acetylglucosaminyltransferase I (Gn TI ), a key enzyme in the formation of complex N ‐glycans, have been identified in several algal species, Gn TI ‐dependent N ‐glycans have not been detected so far. We have performed an N ‐glycoproteomic analysis of the hydrocarbon oils accumulating green microalgae Botryococcus braunii . Thereby, the analysis of intact N ‐glycopeptides allowed the determination of N ‐glycan compositions. Furthermore, insights into the role of N ‐glycosylation in B. braunii were gained from functional annotation of the identified N ‐glycoproteins. In total, 517 unique N ‐glycosylated peptides have been identified, including intact N ‐glycopeptides that harbored N ‐acetylhexosamine (HexNAc) at the nonreducing end. Surprisingly, these Gn TI ‐dependent N ‐glycans were also found to be modified with (di)methylated hexose. The identification of Gn TI ‐dependent N ‐glycans in combination with N ‐glycan methylation in B . braunii revealed an uncommon type of N ‐glycan processing in this microalgae.