Chitobiose phosphorylase from Vibrio proteolyticus, a member of glycosyl transferase family 36, has a clan GH-L-like (alpha/alpha)(6) barrel fold

Structure. 2004 Jun;12(6):937-47. doi: 10.1016/j.str.2004.03.027.


Vibrio proteolyticus chitobiose phosphorylase (ChBP) belongs to glycosyl transferase family 36 (GT-36), and catalyzes the reversible phosphorolysis of chitobiose into alpha-GlcNAc-1-phosphate and GlcNAc with inversion of the anomeric configuration. As the first known structures of a GT-36 enzyme, we determined the crystal structure of ChBP in a ternary complex with GlcNAc and SO(4). It is also the first structures of an inverting phosphorolytic enzyme in a complex with a sugar and a sulfate ion, and reveals a pseudo-ternary complex structure of enzyme-sugar-phosphate. ChBP comprises a beta sandwich domain and an (alpha/alpha)(6) barrel domain, constituting a distinctive structure among GT families. Instead, it shows significant structural similarity with glycoside hydrolase (GH) enzymes, glucoamylases (GH-15), and maltose phosphorylase (GH-65) in clan GH-L. The structural similarity reported here, together with distant sequence similarities between ChBP and GHs, led to the reclassification of family GT-36 into a novel GH family, namely GH-94.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins
  • Binding Sites
  • Carbohydrates / chemistry
  • Crystallography, X-Ray
  • Dimerization
  • Glucan 1,4-alpha-Glucosidase / chemistry
  • Glucosyltransferases / chemistry
  • Glycoside Hydrolases / chemistry
  • Glycosyltransferases / chemistry*
  • Models, Molecular
  • Molecular Sequence Data
  • N-Acetylglucosaminyltransferases / chemistry*
  • Protein Binding
  • Protein Conformation
  • Protein Folding
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Software
  • Substrate Specificity
  • Sulfates / chemistry
  • Vibrio / enzymology*


  • Bacterial Proteins
  • Carbohydrates
  • Sulfates
  • Glycosyltransferases
  • Glucosyltransferases
  • N,N'-diacetylchitobiose phosphorylase
  • N-Acetylglucosaminyltransferases
  • maltose phosphorylase
  • Glycoside Hydrolases
  • Glucan 1,4-alpha-Glucosidase