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  • Enzymatic characterization and molecular modeling of an evolutionarily interesting fungal β-N-acetylhexosaminidase.

Enzymatic characterization and molecular modeling of an evolutionarily interesting fungal β-N-acetylhexosaminidase.

The FEBS journal (2011-05-14)
Helena Ryšlavá, Alžběta Kalendová, Veronika Doubnerová, Přemysl Skočdopol, Vinay Kumar, Zdeněk Kukačka, Petr Pompach, Ondřej Vaněk, Kristýna Slámová, Pavla Bojarová, Natallia Kulik, Rudiger Ettrich, Vladimír Křen, Karel Bezouška
ABSTRACT

Fungal β-N-acetylhexosaminidases are inducible extracellular enzymes with many biotechnological applications. The enzyme from Penicillium oxalicum has unique enzymatic properties despite its close evolutionary relationship with other fungal hexosaminidases. It has high GalNAcase activity, tolerates substrates with the modified N-acyl group better and has some other unusual catalytic properties. In order to understand these features, we performed isolation, biochemical and enzymological characterization, molecular cloning and molecular modelling. The native enzyme is composed of two catalytic units (65 kDa each) and two propeptides (15 kDa each), yielding a molecular weight of 160 kDa. Enzyme deglycosylated by endoglycosidase H had comparable activity, but reduced stability. We have cloned and sequenced the gene coding for the entire hexosaminidase from P. oxalicum. Sufficient sequence identity of this hexosaminidase with the structurally solved enzymes from bacteria and humans with complete conservation of all catalytic residues allowed us to construct a molecular model of the enzyme. Results from molecular dynamics simulations and substrate docking supported the experimental kinetic and substrate specificity data and provided a molecular explanation for why the hexosaminidase from P. oxalicum is unique among the family of fungal hexosaminidases.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Endoglycosidase H from Streptomyces plicatus, recombinant, expressed in E. coli, buffered aqueous solution
Sigma-Aldrich
Endoglycosidase F2 from Elizabethkingia miricola, recombinant, expressed in E. coli, 20 U/mg
Sigma-Aldrich
Endoglycosidase F1 from Elizabethkingia miricola, recombinant, expressed in E. coli, ≥16 U/mg, buffered aqueous solution
Sigma-Aldrich
Endoglycosidase F3 from Elizabethkingia miricola, recombinant, expressed in E. coli, 30 U/mg