PDBsum entry: 1w8o

Hydrolase

PDB id: 1w8o

Contents

Protein chain

601 a.a. *

Ligands

LBT

CIT

GOL ×4

Metals

_NA

Waters ×709

* Residue conservation analysis

PDB id:

1w8o

Name:

Hydrolase

Title:

Contribution of the active site aspartic acid to catalysis in the bacterial neuraminidase from micromonospora viridifaciens

Structure:

Bacterial sialidase. Chain: a. Fragment: residues 47-647. Engineered: yes. Mutation: yes

Source:

Micromonospora viridifaciens. Organism_taxid: 1881. Atcc: 31146. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.70Å R-factor: 0.164 R-free: 0.197

Authors:

S.Newstead,J.N.Watson,V.Dookhun,A.J.Bennet,G.Taylor

Key ref:

J.N.Watson et al. (2004). Contribution of the active site aspartic acid to catalysis in the bacterial neuraminidase from Micromonospora viridifaciens. FEBS Lett, 577, 265-269. PubMed id: 15527797 DOI: 10.1016/j.febslet.2004.10.016

Date:

24-Sep-04 Release date: 29-Sep-04

Protein chain

Q02834  (NANH_MICVI) -  Sialidase

Seq: 647 a.a.

Struc: 601 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.3.2.1.18 - Exo-alpha-sialidase.
• Reaction: Hydrolysis of alpha-(2->3)-, alpha-(2->6)-, alpha-(2->8)-glycosidic linkages of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates.

 Gene Ontology (GO) functional annotation 

• Cellular component: extracellular region (1 term)
• Biological process: metabolic process (2 terms)
• Biochemical function: hydrolase activity (6 terms)

DOI no: 10.1016/j.febslet.2004.10.016

FEBS Lett 577:265-269 (2004)

PubMed id: 15527797

Contribution of the active site aspartic acid to catalysis in the bacterial neuraminidase from Micromonospora viridifaciens.

J.N.Watson, S.Newstead, V.Dookhun, G.Taylor, A.J.Bennet.

ABSTRACT

A recombinant D92G mutant sialidase from Micromonospora viridifaciens has been cloned, expressed and purified. Kinetic studies reveal that the replacement of the conserved aspartic acid with glycine results in a catalytically competent retaining sialidase that possesses significant activity against activated substrates. The contribution of this aspartate residue to the free energy of hydrolysis for natural substrates is greater than 19 kJ/mol. The three dimensional structure of the D92G mutant shows that the removal of aspartic acid 92 causes no significant re-arrangement of the active site, and that an ordered water molecule substitutes for the carboxylate group of D92.

Selected figure(s)

Figure 1.
Fig. 1. Effect of temperature on the relative rates of sialidase-catalyzed hydrolysis of MU-αNeu5Ac at pH 5.25 for the wild-type enzyme ( operator ) and D92G mutant (•). Data for wild-type reproduced with permission of the American Chemical Society.

Figure 5.
Fig. 5. Superimposition of the active site residues of wild-type catalytic domain with Neu5Ac2en (PDB 1EUS) and the D92G-Neu5Ac2en complex. Residues of the wild-type structure are shown in slate and of the mutant in wheat. The hydrogen bonding interactions are drawn as green dotted lines; the interaction of Asp92 with Asp85 is shown in orange.

The above figures are reprinted by permission from the Federation of European Biochemical Societies: FEBS Lett (2004, 577, 265-269) copyright 2004.

Figures were selected by an automated process.