The structure of an archaeal β-glucosaminidase provides insight into glycoside hydrolase evolution

Shouhei Mine, Masahiro Watanabe, Saori Kamachi, Yoshito Abe, Tadashi Ueda

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

The archaeal exo-β-D-glucosaminidase (GlmA) is a dimeric enzyme that hydrolyzes chitosan oligosaccharides into monomer glucosamines. GlmA is a member of the glycosidase hydrolase (GH)-A superfamily-subfamily 35 and is a novel enzyme in terms of its primary structure. Here, we present the crystal structure of GlmA in complex with glucosamine at 1.27 Å resolution. The structure reveals that a monomeric form of GlmA shares structural homology with GH42 β-galactosidases, whereas most of the spatial positions of the active site residues are identical to those of GH35 β-galactosidases. We found that upon dimerization, the active site of GlmA changes shape, enhancing its ability to hydrolyze the smaller substrate in a manner similar to that of homotrimeric GH42 β-galactosidase. However, GlmA can differentiate glucosamine from galactose based on one charged residue while using the "evolutionary heritage residue" it shares with GH35 β-galactosidase. Our study suggests that GH35 and GH42 β-galactosidases evolved by exploiting the structural features of GlmA.

Original languageEnglish
Pages (from-to)4996-5006
Number of pages11
JournalJournal of Biological Chemistry
Volume292
Issue number12
DOIs
Publication statusPublished - Mar 24 2017

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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