2BER

Y370G Active Site Mutant of the Sialidase from Micromonospora viridifaciens in complex with beta-Neu5Ac (sialic acid).


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.140 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure and Mechanism of Action of an Inverting Mutant Sialidase.

Newstead, S.Watson, J.N.Knoll, T.L.Bennet, A.J.Taylor, G.L.

(2005) Biochemistry 44: 9117

  • DOI: 10.1021/bi050517t

  • PubMed Abstract: 
  • Mutagenesis of the conserved tyrosine (Y370) of the Micromonospora viridifaciens sialidase to small amino acids changes the mechanism of catalysis from retention of anomeric configuration to inversion [Watson, J. N., et al. (2003) Biochemistry 42, 12 ...

    Mutagenesis of the conserved tyrosine (Y370) of the Micromonospora viridifaciens sialidase to small amino acids changes the mechanism of catalysis from retention of anomeric configuration to inversion [Watson, J. N., et al. (2003) Biochemistry 42, 12682-12690]. For the Y370G mutant enzyme-catalyzed hydrolysis of a series of aryl sialosides and 3'-sialyllactose, the derived Brønsted parameters (beta(lg)) on k(cat) and k(cat)/K(m) are -0.63 +/- 0.05 and -0.80 +/- 0.08, respectively. Thus, for the Y370G enzyme, glycosidic C-O bond cleavage is rate-determining. Analysis of the activity of the Y370G mutant and wild-type enzymes against a substrate [3,4-dihydro-2H-pyrano[3,2-c]pyridinium alpha-d-N-acetylneuraminide (DHP-alphaNeu5Ac)] whose hydrolysis cannot be accelerated by acid catalysis is consistent with these reactions proceeding via S(N)1 and S(N)2 mechanisms, respectively. The overall structure of the Y370G mutant sialidase active site is very similar to the previously reported wild-type structure [Gaskell, A., et al. (1995) Structure 3, 1197-1205], although removal of the tyrosine residue creates two significant changes to the active site. First, the anomeric oxygen atom of the hydrolysis product (beta-N-acetylneuraminic acid) and four water molecules bind in the large cavity created by the Y370G mutation. Second, the side chain of Asn310 moves to make a strong hydrogen bond to one of the bound water molecules.


    Organizational Affiliation

    Centre for Biomolecular Science, University of St. Andrews, St. Andrews, Fife KY16 9ST, Scotland.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
BACTERIAL SIALIDASE
A
601Micromonospora viridifaciensGene Names: nedA
EC: 3.2.1.18
Find proteins for Q02834 (Micromonospora viridifaciens)
Go to UniProtKB:  Q02834
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
SLB
Query on SLB

Download SDF File 
Download CCD File 
A
5-N-ACETYL-BETA-D-NEURAMINIC ACID
BETA-SIALIC ACID
C11 H19 N O9
SQVRNKJHWKZAKO-PFQGKNLYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.140 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 55.440α = 90.00
b = 49.535β = 101.74
c = 107.041γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
SCALAdata scaling
AMoREphasing
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-04-04
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance