Three-dimensional structures of the Mn and Mg dTDP complexes of the family GT-2 glycosyltransferase SpsA: a comparison with related NDP-sugar glycosyltransferases

J Mol Biol. 2001 Dec 7;314(4):655-61. doi: 10.1006/jmbi.2001.5159.


The vast majority of glycosidic-bond synthesis in nature is performed by glycosyltransferases, which use activated glycosides as the sugar donor. Typically, the activated leaving group is a nucleoside phosphate, lipid phosphate or phosphate. The nucleotide-sugar-dependent glycosyltransferases fall into over 50 sequence-based families, with the largest and most widespread family of inverting transferases named family GT-2. Here, we present the three-dimensional crystal structure of SpsA, the first and currently the only structural representative from family GT-2, in complex with both Mn-dTDP and Mg-dTDP at a resolution of 2 A. These structures reveal how SpsA and related enzymes may display nucleotide plasticity and permit a comparison of the catalytic centre of this enzyme with those from related sequence families whose three-dimensional structures have recently been determined. Family GT-2 enzymes, together with enzymes from families 7, 13 and 43, appear to form a clan of related structures with identical catalytic apparatus and reaction mechanism.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / enzymology*
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / classification
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Catalytic Domain
  • Crystallography, X-Ray
  • Evolution, Molecular
  • Glycosyltransferases / chemistry*
  • Glycosyltransferases / classification
  • Glycosyltransferases / metabolism*
  • Magnesium / metabolism*
  • Manganese / metabolism*
  • Models, Molecular
  • Protein Conformation
  • Thymine Nucleotides / metabolism*
  • Uridine Diphosphate / metabolism


  • Bacterial Proteins
  • SpsA protein, Streptococcus pneumoniae
  • Thymine Nucleotides
  • Manganese
  • thymidine 5'-diphosphate
  • Uridine Diphosphate
  • Glycosyltransferases
  • Magnesium