1WCS

A mutant of Trypanosoma rangeli sialidase displaying trans-sialidase activity


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.336 
  • R-Value Work: 0.244 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

A Sialidase Mutant Displaying Trans-Sialidase Activity

Paris, G.Ratier, L.Amaya, M.F.Nguyen, T.Alzari, P.M.Frasch, C.

(2005) J.Mol.Biol. 345: 923

  • DOI: 10.1016/j.jmb.2004.09.031

  • PubMed Abstract: 
  • Trypanosoma cruzi, the agent of Chagas disease, expresses a modified sialidase, the trans-sialidase, which transfers sialic acid from host glycoconjugates to beta-galactose present in parasite mucins. Another American trypanosome, Trypanosoma rangeli ...

    Trypanosoma cruzi, the agent of Chagas disease, expresses a modified sialidase, the trans-sialidase, which transfers sialic acid from host glycoconjugates to beta-galactose present in parasite mucins. Another American trypanosome, Trypanosoma rangeli, expresses a homologous protein that has sialidase activity but is devoid of transglycosidase activity. Based on the recently determined structures of T.rangeli sialidase (TrSA) and T.cruzi trans-sialidase (TcTS), we have now constructed mutants of TrSA with the aim of studying the relevant residues in transfer activity. Five mutations, Met96-Val, Ala98-Pro, Ser120-Tyr, Gly249-Tyr and Gln284-Pro, were enough to obtain a sialidase mutant (TrSA(5mut)) with trans-sialidase activity; and a sixth mutation increased the activity to about 10% that of wild-type TcTS. The crystal structure of TrSA(5mut) revealed the formation of a trans-sialidase-like binding site for the acceptor galactose, primarily defined by the phenol group of Tyr120 and the indole ring of Trp313, which adopts a new conformation, similar to that in TcTS, induced by the Gln284-Pro mutation. The transition state analogue 2,3-didehydro-2-deoxy-N-acetylneuraminic acid (DANA), which inhibits sialidases but is a poor inhibitor of trans-sialidase, was used to probe the active site conformation of mutant enzymes. The results show that the presence of a sugar acceptor binding-site, the fine-tuning of protein-substrate interactions and the flexibility of crucial active site residues are all important to achieve transglycosidase activity from the TrSA sialidase scaffold.


    Organizational Affiliation

    Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, CONICET-UNSAM, CC30, 1650, San Martín, Buenos Aires, Argentina. gparis@iib.unsam.edu.ar




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SIALIDASE
A
641Trypanosoma rangeliEC: 3.2.1.18
Find proteins for O44049 (Trypanosoma rangeli)
Go to UniProtKB:  O44049
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.336 
  • R-Value Work: 0.244 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 94.691α = 90.00
b = 94.691β = 90.00
c = 156.335γ = 90.00
Software Package:
Software NamePurpose
AMoREphasing
SCALAdata scaling
REFMACrefinement
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-12-15
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance