Identification of the catalytic acid-base residue of arthrobacter endo-β-N-acetylglucosaminidase by chemical rescue of an inactive mutant

Kiyotaka Fujita, Reiko Sato, Kazunori Toma, Kanefumi Kitahara, Toshihiko Suganuma, Kenji Yamamoto, Kaoru Takegawa

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Arthrobacter endo-β-N-acetylglucosaminidase (Endo-A), a member of glycoside hydrolase (GH) family 85, catalyses the hydrolysis and transglycosylation of asparagine-linked oligosaccharides of glycoproteins with retention of anomeric configuration. Glu-173 of Endo-A is a catalytically essential amino acid residue, and the corresponding residue is conserved in all GH family 85 members. The catalytic activity of Endo-A E173A mutant was rescued by the addition of sodium azide or sodium formate. Furthermore, the produced β-glycosyl azide (Man 5GlcNAc-β-N 3) retained the anomeric configuration, indicating that Glu-173 is the catalytic acid-base residue of Endo-A. This is the first identification of the catalytic residue for GH family 85 endo-β-N-acetylglucosaminidases.

Original languageEnglish
Pages (from-to)301-306
Number of pages6
JournalJournal of biochemistry
Issue number3
Publication statusPublished - Sep 1 2007
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology

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