Hydrophobic Interactions Contribute to Conformational Stabilization of Endoglycoceramidase II by Mechanism-Based Probes.

Abstract

Small compound active site interactors receive considerable attention for their ability to positively influence the fold of glycosidases. Endoglycoceramidase II (EGCII) from Rhodococcus sp. is an endo-β-glucosidase releasing the complete glycan from ceramide in glycosphingolipids. Cleavage of the β-glycosidic linkage between glucose and ceramide is also catalyzed by glucocerebrosidase (GBA), the exo-β-glucosidase deficient in Gaucher disease. We demonstrate that established β-glucoside-configured cyclophellitol-type activity-based probes (ABPs) for GBA also are effective, mechanism-based, and irreversible inhibitors of EGCII. The stability of EGCII is markedly enhanced by formation of covalent complexes with cyclophellitol ABPs substituted with hydrophobic moieties, as evidenced by an increased melting temperature, resistance against tryptic digestion, changes in (15)N-(1)H transverse relaxation optimized spectroscopy spectra of the [(15)N]Leu-labeled enzyme, and relative hydrophobicity as determined by 8-anilino-1-naphthalenesulfonic acid fluorescence. The stabilization of EGCII conformation correlates with the shape and hydrophobicity of the substituents of the ABPs. We conclude that the amphipathic active site binders with aliphatic moieties act as a "hydrophobic zipper" on the flexible EGCII protein structure.

• Authors: Fredj Ben Bdira, Jianbing Jiang, Wouter Kallemeijn, Annett de Haan, Bogdan I Florea, Boris Bleijlevens, Rolf Boot, Herman S Overkleeft, Johannes M Aerts, Marcellus Ubbink
• Journal: Biochemistry (Biochemistry) Vol. 55 Issue 34 Pg. 4823-35 (08 30 2016) ISSN: 1520-4995 [Electronic] United States
• PMID: 27455091 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Proteins
• Cyclohexanols
• Molecular Probes
• Recombinant Proteins
• cyclophellitol
• Glycoside Hydrolases
• endoglycoceramidase
• Glucosylceramidase

Topics

• Amino Acid Sequence
• Bacterial Proteins (chemistry, genetics, metabolism)
• Catalytic Domain
• Cyclohexanols (chemistry)
• Enzyme Stability
• Gaucher Disease (enzymology)
• Glucosylceramidase (chemistry, genetics, metabolism)
• Glycoside Hydrolases (chemistry, genetics, metabolism)
• Humans
• Hydrophobic and Hydrophilic Interactions
• Models, Molecular
• Molecular Probes (chemistry)
• Protein Conformation
• Recombinant Proteins (chemistry, genetics, metabolism)
• Rhodococcus (enzymology, genetics)
• Structural Homology, Protein