PDBsum entry: 1ks5

Hydrolase

PDB id: 1ks5

Contents

Protein chain

223 a.a. *

Waters ×125

* Residue conservation analysis

PDB id:

1ks5

Name:

Hydrolase

Title:

Structure of aspergillus niger endoglucanase

Structure:

Endoglucanase a. Chain: a. Fragment: catalytic domain. Ec: 3.2.1.4

Source:

Aspergillus niger. Organism_taxid: 5061. Strain: cbs 554.65

Resolution:

2.10Å R-factor: 0.175 R-free: 0.191

Authors:

S.Khademi,D.Zhang,S. M.Swanson,A.Wartenberg,C.Witte,E. F.Meyer

Key ref:

S.Khademi et al. (2002). Determination of the structure of an endoglucanase from Aspergillus niger and its mode of inhibition by palladium chloride. Acta Crystallogr D Biol Crystallogr, 58, 660-667. PubMed id: 11914491 DOI: 10.1107/S0907444902003360

Date:

10-Jan-02 Release date: 21-Jan-03

Protein chain

O74705  (O74705_ASPNG) -  Endoglucanase A (Precursor)

Seq: 239 a.a.

Struc: 223 a.a.

Enzyme reactions

• Enzyme class: E.C.3.2.1.4 - Cellulase.
• Reaction: Endohydrolysis of 1,4-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans.

 Gene Ontology (GO) functional annotation 

• Biological process: metabolic process (2 terms)
• Biochemical function: hydrolase activity (4 terms)

DOI no: 10.1107/S0907444902003360

Acta Crystallogr D Biol Crystallogr 58:660-667 (2002)

PubMed id: 11914491

Determination of the structure of an endoglucanase from Aspergillus niger and its mode of inhibition by palladium chloride.

S.Khademi, D.Zhang, S.M.Swanson, A.Wartenberg, K.Witte, E.F.Meyer.

ABSTRACT

The fungus Aspergillus niger is a main source of industrial cellulase. beta-1,4-Endoglucanase is the major component of cellulase from A. niger. In spite of widespread applications, little is known about the structure of this enzyme. Here, the structure of beta-1,4-endoglucanase from A. niger (EglA) was determined at 2.1 A resolution. Although there is a low sequence identity between EglA and CelB2, another member of family 12, the three-dimensional structures of their core regions are quite similar. The structural differences are mostly found in the loop regions, where CelB2 has an extra beta-sheet (beta-sheet C) at the non-reducing end of the binding cleft of the native enzyme. Incubation of EglA with PdCl(2) irreversibly inhibits the EglA activity. Structural studies of the enzyme-palladium complex show that three Pd(2+) ions bind to each EglA molecule. One of the Pd(2+) ions forms a coordinate covalent bond with Met118 S(delta) and the nucleophilic Glu116 O(epsilon1) at the active site of the enzyme. The other two Pd(2+) ions bind on the surface of the protein. Binding of Pd(2+) ions to EglA does not change the general conformation of the backbone of the protein significantly. Based on this structural study, one can conclude that the palladium ion directly binds to and blocks the active site of EglA and thus inactivates the enzyme.

Selected figure(s)

Figure 2.
Figure 2 Ribbon stereo diagram of EglA. -sheet A is in blue, -sheet B is in green and helices are in red.

Figure 6.
Figure 6 (a) The structure of EglA complexed with three Pd^2+ ions, B, C and D. (b), (c) and (d) The binding site for Pd^2+ ions B, C and D, respectively. The electron-density maps (F[o] - F[c]) for the three Pd^2+ ions are contoured at 7.0 . The Pd^2+ ions are in green.

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2002, 58, 660-667) copyright 2002.

Figures were selected by an automated process.