1ks4
From Proteopedia
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The structure of Aspergillus niger endoglucanase-palladium complex
Overview
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.
About this Structure
1KS4 is a Single protein structure of sequence from Aspergillus niger with PD as ligand. Active as Cellulase, with EC number 3.2.1.4 Full crystallographic information is available from OCA.
Reference
Determination of the structure of an endoglucanase from Aspergillus niger and its mode of inhibition by palladium chloride., Khademi S, Zhang D, Swanson SM, Wartenberg A, Witte K, Meyer EF, Acta Crystallogr D Biol Crystallogr. 2002 Apr;58(Pt 4):660-7. Epub 2002, Mar 22. PMID:11914491
Page seeded by OCA on Sun Nov 25 01:50:25 2007
