3VW5

Crystal structure of sugar epimerase from ruminal bacterium

Summary for 3VW5

• Entry DOI: 10.2210/pdb3vw5/pdb
• Descriptor: Cellobiose 2-epimerase (2 entities in total)
• Functional Keywords: (alpha/alpha)6 barrel fold, epimerase, carbohydrate/sugar binding, epimerization, isomerase
• Biological source: Ruminococcus albus
• Total number of polymer chains: 3
• Total formula weight: 136088.18

Authors

Fujiwara, T.,Saburi, W.,Tanaka, I.,Yao, M. (deposition date: 2012-08-02, release date: 2013-06-26, Last modification date: 2023-11-08)

Primary citation

Fujiwara, T.,Saburi, W.,Inoue, S.,Mori, H.,Matsui, H.,Tanaka, I.,Yao, M.
Crystal structure of Ruminococcus albus cellobiose 2-epimerase: structural insights into epimerization of unmodified sugar
Febs Lett., 587:840-846, 2013

PubMed 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.

PubMed: 23462136
DOI: 10.1016/j.febslet.2013.02.007

Experimental method

X-RAY DIFFRACTION (2.6 Å)