1. Imino‐ and Azasugar Protonation Inside Human Acid β‐Glucosidase, the Enzyme that is Defective in Gaucher Disease
- Author
-
Francesca Cardona, Mikael Bols, Bo Wang, Andrea Goti, Camilla Matassini, Amelia Morrone, and Julia Warren
- Subjects
Ceramide ,1-Deoxynojirimycin ,Stereochemistry ,Protonation ,010402 general chemistry ,01 natural sciences ,Catalysis ,Photoinduced electron transfer ,Hydrolysis ,chemistry.chemical_compound ,medicine ,Humans ,Enzyme Inhibitors ,Enzyme Assays ,Fluorescent Dyes ,chemistry.chemical_classification ,biology ,010405 organic chemistry ,Chemistry ,Active site ,General Chemistry ,General Medicine ,Phenanthrenes ,0104 chemical sciences ,Pharmacological chaperone ,Enzyme ,biology.protein ,Glucosylceramidase ,Protons ,Glucocerebrosidase ,medicine.drug ,Imino Pyranoses - Abstract
Gaucher disease is caused by mutations in human acid β-glucosidase or glucocerebrosidase (GCase), the enzyme responsible for hydrolysis of glucosyl ceramide in the lysosomes. Imino- and azasugars such as 1-deoxynojirimycin and isofagomine are strong inhibitors of the enzyme and are of interest in pharmacological chaperone therapy of the disease. Despite several crystal structures of the enzyme with the imino- and azasugars bound in the active site having been resolved, the actual acid-base chemistry of the binding is not known. In this study we show, using photoinduced electron transfer (PET), that 1-deoxynojirimycin and isofagomine derivatives are protonated by human acid β-glucosidase when bound, even if they are completely unprotonated outside the enzyme. While isofagomine derivative protonation to some degree was foreshadowed by earlier crystal structures, 1-deoxynojirimycin derivatives were not believed to act as basic amines in the enzyme.
- Published
- 2020