Evidence of ternary complex formation in Trypanosoma cruzi trans-sialidase catalysis

J Biol Chem. 2014 Jan 3;289(1):423-36. doi: 10.1074/jbc.M112.399303. Epub 2013 Nov 5.

Abstract

Trypanosoma cruzi trans-sialidase (TcTS) is a key target protein for Chagas disease chemotherapy. In this study, we investigated the implications of active site flexibility on the biochemical mechanism of TcTS. Molecular dynamics studies revealed remarkable plasticity in the TcTS catalytic site, demonstrating, for the first time, how donor substrate engagement with the enzyme induces an acceptor binding site in the catalytic pocket that was not previously captured in crystal structures. Furthermore, NMR data showed cooperative binding between donor and acceptor substrates, supporting theoretical results. In summary, our data put forward a coherent dynamic framework to understand how a glycosidase evolved its highly efficient trans-glycosidase activity.

Keywords: Carbohydrate Glycoconjugate; Enzyme Mechanisms; Enzyme Structure; Glycosidases; Molecular Dynamics; Nuclear Magnetic Resonance; Sialic Acid; Sialidase; Trypanosoma cruzi; trans-Sialidase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Catalytic Domain
  • Evolution, Molecular*
  • Glycoproteins
  • Molecular Dynamics Simulation*
  • Neuraminidase
  • Nuclear Magnetic Resonance, Biomolecular
  • Protozoan Proteins / chemistry*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism
  • Trypanosoma cruzi / enzymology*
  • Trypanosoma cruzi / genetics

Substances

  • Glycoproteins
  • Protozoan Proteins
  • trans-sialidase
  • Neuraminidase