3RWK

First crystal structure of an endo-inulinase, from Aspergillus ficuum: structural analysis and comparison with other GH32 enzymes.

Summary for 3RWK

• Entry DOI: 10.2210/pdb3rwk/pdb
• Descriptor: Inulinase, alpha-D-mannopyranose-(1-3)-alpha-D-mannopyranose-(1-6)-alpha-D-mannopyranose, beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (8 entities in total)
• Functional Keywords: endo-inulinase, glycoside hydrolase family 32, catalytic mechanism, glycosidase hydrolase family 32, glycosylation, cytosol, hydrolase
• Biological source: Aspergillus ficuum
• Cellular location: Secreted: O94220
• Total number of polymer chains: 1
• Total formula weight: 57460.96

Authors

Michaux, C.,Pouyez, J.,Roussel, G.,Mayard, A.,Vandamme, A.M.,Housen, I.,Wouters, J. (deposition date: 2011-05-09, release date: 2012-07-18, Last modification date: 2024-10-16)

Primary citation

Pouyez, J.,Mayard, A.,Vandamme, A.M.,Roussel, G.,Perpete, E.A.,Wouters, J.,Housen, I.,Michaux, C.
First crystal structure of an endo-inulinase, INU2, from Aspergillus ficuum: Discovery of an extra-pocket in the catalytic domain responsible for its endo-activity.
Biochimie, 94:2423-2430, 2012

PubMed Abstract: Endo-inulinase is a member of glycosidase hydrolase family 32 (GH32) degrading fructans of the inulin type with an endo-cleavage mode and is an important class of industrial enzyme. In the present study, we report the first crystal structure of an endo-inulinase, INU2, from Aspergillus ficuum at 1.5 Å. It was solved by molecular replacement with the structure of exo-inulinase as search model. The 3D structure presents a bimodular arrangement common to other GH32 enzymes: a N-terminal 5-fold β-propeller catalytic domain with four β-sheets and a C-terminal β-sandwich domain organized in two β-sheets with five β-strands. The structural analysis and comparison with other GH32 enzymes reveal the presence of an extra pocket in the INU2 catalytic site, formed by two loops and the conserved motif W-M(I)-N-D(E)-P-N-G. This cavity would explain the endo-activity of the enzyme, the critical role of Trp40 and particularly the cleavage at the third unit of the inulin(-like) substrates. Crystal structure at 2.1 Å of INU2 complexed with fructosyl molecules, experimental digestion data and molecular modelling studies support these hypotheses.

PubMed: 22750808
DOI: 10.1016/j.biochi.2012.06.020

Experimental method

X-RAY DIFFRACTION (2.1 Å)