Structure of human POFUT2: insights into thrombospondin type 1 repeat fold and O-fucosylation

EMBO J. 2012 Jul 18;31(14):3183-97. doi: 10.1038/emboj.2012.143.


Protein O-fucosylation is a post-translational modification found on serine/threonine residues of thrombospondin type 1 repeats (TSR). The fucose transfer is catalysed by the protein O-fucosyltransferase 2 (POFUT2) and >40 human proteins contain the TSR consensus sequence for POFUT2-dependent fucosylation. To better understand O-fucosylation on TSR, we carried out a structural and functional analysis of human POFUT2 and its TSR substrate. Crystal structures of POFUT2 reveal a variation of the classical GT-B fold and identify sugar donor and TSR acceptor binding sites. Structural findings are correlated with steady-state kinetic measurements of wild-type and mutant POFUT2 and TSR and give insight into the catalytic mechanism and substrate specificity. By using an artificial mini-TSR substrate, we show that specificity is not primarily encoded in the TSR protein sequence but rather in the unusual 3D structure of a small part of the TSR. Our findings uncover that recognition of distinct conserved 3D fold motifs can be used as a mechanism to achieve substrate specificity by enzymes modifying completely folded proteins of very wide sequence diversity and biological function.

MeSH terms

  • Crystallography, X-Ray
  • Fucose / chemistry
  • Fucose / genetics
  • Fucose / metabolism
  • Fucosyltransferases / chemistry*
  • Fucosyltransferases / genetics
  • Fucosyltransferases / metabolism
  • Glycosylation
  • Humans
  • Protein Folding*
  • Protein Structure, Tertiary
  • Repetitive Sequences, Amino Acid
  • Structure-Activity Relationship


  • Fucose
  • Fucosyltransferases
  • POFUT2 protein, human