Structural Snapshots and Loop Dynamics along the Catalytic Cycle of Glycosyltransferase GpgS

Structure. 2017 Jul 5;25(7):1034-1044.e3. doi: 10.1016/j.str.2017.05.009. Epub 2017 Jun 15.


Glycosyltransferases (GTs) play a central role in nature. They catalyze the transfer of a sugar moiety to a broad range of acceptor substrates. GTs are highly selective enzymes, allowing the recognition of subtle structural differences in the sequences and stereochemistry of their sugar and acceptor substrates. We report here a series of structural snapshots of the reaction center of the retaining glucosyl-3-phosphoglycerate synthase (GpgS). During this sequence of events, we visualize how the enzyme guides the substrates into the reaction center where the glycosyl transfer reaction takes place, and unveil the mechanism of product release, involving multiple conformational changes not only in the substrates/products but also in the enzyme. The structural data are further complemented by metadynamics free-energy calculations, revealing how the equilibrium of loop conformations is modulated along these itineraries. The information reported here represent an important contribution for the understanding of GT enzymes at the molecular level.

Keywords: carbohydrate biosynthesis; carbohydrate modifying enzymes; enzyme catalysis; enzyme dynamics; enzyme mechanism; enzyme structure; glycosyltransferases; lipopolysaccharide; mycobacteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalytic Domain*
  • Glucosyltransferases / chemistry*
  • Glucosyltransferases / metabolism
  • Molecular Dynamics Simulation
  • Protein Binding
  • Substrate Specificity


  • Glucosyltransferases
  • glucosyl-3-phosphoglycerate synthase, Mycobacterium tuberculosis