1N1V

Trypanosoma rangeli sialidase in complex with DANA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.219 
  • R-Value Work: 0.178 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The high resolution structures of free and inhibitor-bound Trypanosoma rangeli sialidase and its comparison with T. cruzi trans-sialidase

Amaya, M.F.Buschiazzo, A.Nguyen, T.Alzari, P.M.

(2003) J.Mol.Biol. 325: 773-784

  • Primary Citation of Related Structures:  1N1S, 1N1T, 1N1Y

  • PubMed Abstract: 
  • The structure of the recombinant Trypanosoma rangeli sialidase (TrSA) has been determined at 1.6A resolution, and the structures of its complexes with the transition state analog inhibitor 2-deoxy-2,3-dehydro-N-acetyl-neuraminic acid (DANA), Neu-5-Ac ...

    The structure of the recombinant Trypanosoma rangeli sialidase (TrSA) has been determined at 1.6A resolution, and the structures of its complexes with the transition state analog inhibitor 2-deoxy-2,3-dehydro-N-acetyl-neuraminic acid (DANA), Neu-5-Ac-thio-alpha(2,3)-galactoside (NATG) and N-acetylneuraminic acid (NANA) have been determined at 1.64A, 2.1A and 2.85A, respectively. The 3D structure of TrSA is essentially identical to that of the natural enzyme, except for the absence of covalently attached sugar at five distinct N-glycosylation sites. The protein exhibits a topologically rigid active site architecture that is unaffected by ligand binding. The overall binding of DANA to the active site cleft is similar to that observed for other viral and bacterial sialidases, dominated by the interactions of the inhibitor carboxylate with the conserved arginine triad. However, the interactions of the other pyranoside ring substituents (hydroxyl, N-acetyl and glycerol moieties) differ between trypanosomal, bacterial and viral sialidases, providing a structural basis for specific inhibitor design. Sialic acid is found to bind the enzyme with the sugar ring in a distorted (half-chair or boat) conformation and the 2-OH hydroxyl group at hydrogen bonding distance of the carboxylate of Asp60, substantiating a direct catalytic role for this residue. A detailed comparison of TrSA with the closely related structure of T.cruzi trans-sialidase (TcTS) reveals a highly conserved catalytic center, where subtle structural differences account for strikingly different enzymatic activities and inhibition properties. The structure of TrSA in complex with NATG shows the active site cleft occupied by a smaller compound which could be identified as DANA, probably the product of a hydrolytic side reaction. Indeed, TrSA (but not TcTS) was found to cleave O and S-linked sialylated substrates, further stressing the functional differences between trypanosomal sialidases and trans-sialidases.


    Related Citations: 
    • Structural basis of sialyltransferase activity in trypanosomal sialidases
      Buschiazzo, A.,Tavares, G.A.,Campetella, O.,Spinelli, S.,Cremona, M.L.,Paris, G.,Amaya, M.F.,Frasch, A.C.,Alzari, P.M.
      (2000) Embo J. 19: 16


    Organizational Affiliation

    Unité de Biochimie Structurale, CNRS URA 2185, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris cédex 15, France.




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
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
DAN
Query on DAN

Download SDF File 
Download CCD File 
A
2-DEOXY-2,3-DEHYDRO-N-ACETYL-NEURAMINIC ACID
C11 H17 N O8
JINJZWSZQKHCIP-UFGQHTETSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
DANKi: 140000 nM BINDINGMOAD
DANKi: 140000 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.219 
  • R-Value Work: 0.178 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 75.862α = 90.00
b = 93.404β = 90.00
c = 105.821γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
REFMACrefinement
DENZOdata reduction
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-01-07
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance