Crystal structure of Ruminococcus albus cellobiose 2-epimerase: Structural insights into epimerization of unmodified sugar

Takaaki Fujiwara, Wataru Saburi, Sota Inoue, Haruhide Mori, Hirokazu Matsui, Isao Tanaka, Min Yao

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Enzymatic epimerization is an important modification for carbohydrates to acquire diverse functions attributable to their stereoisomers. Cellobiose 2-epimerase (CE) catalyzes interconversion between d-glucose and d-mannose residues at the reducing end of β-1,4-linked oligosaccharides. Here, we solved the structure of Ruminococcus albus CE (RaCE). The structure of RaCE showed strong similarity to those of N-acetyl-d-glucosamine 2-epimerase and aldose-ketose isomerase YihS with a high degree of conservation of residues around the catalytic center, although sequence identity between them is low. Based on structural comparison, we found that His184 is required for RaCE activity as the third histidine added to two essential histidines in other sugar epimerases/isomerases. This finding was confirmed by mutagenesis, suggesting a new catalytic mechanism for CE involving three histidines. Structured summary of protein interactions: RaCE and X-ray crystallography (View interaction).

Original languageEnglish
Pages (from-to)840-846
Number of pages7
JournalFEBS Letters
Volume587
Issue number7
DOIs
Publication statusPublished - 2013 Apr 2
Externally publishedYes

Keywords

  • Cellobiose 2-epimerase
  • Deprotonation
  • Structure
  • Unmodified sugar
  • X-ray crystallography

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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