Vinyl Halide-Modified Unsaturated Cyclitols are Mechanism-Based Glycosidase Inhibitors |
| |
| Authors: | Dr. Phillip M. Danby Andrew Jeong Dr. Lyann Sim Dr. Ryan P. Sweeney Jacob F. Wardman Ryan Karimi Dr. Andreas Geissner Dr. Liam J. Worrall Prof. Dr. Jolene. P. Reid Prof. Dr. Natalie C. J. Strynadka Prof. Dr. Stephen G. Withers |
| |
| Affiliation: | 1. Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1 Canada;2. Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1 Canada Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4 Canada;3. Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3 Canada |
| |
| Abstract: | Suitably configured allyl ethers of unsaturated cyclitols act as substrates of β-glycosidases, reacting via allylic cation transition states. Incorporation of halogens at the vinylic position of these carbasugars, along with an activated leaving group, generates potent inactivators of β-glycosidases. Enzymatic turnover of these halogenated cyclitols (F, Cl, Br) displayed a counter-intuitive trend wherein the most electronegative substituents yielded the most labile pseudo-glycosidic linkages. Structures of complexes with the Sulfolobus β-glucosidase revealed similar enzyme-ligand interactions to those seen in complexes with a 2-fluorosugar inhibitor, the lone exception being displacement of tyrosine 322 from the active site by the halogen. Mutation of Y322 to Y322F largely abolished glycosidase activity, consistent with lost interactions at O5, but minimally affected (7-fold) rates of carbasugar hydrolysis, yielding a more selective enzyme for unsaturated cyclitol ether hydrolysis. |
| |
| Keywords: | Carbasugars Covalent Inhibitors Glycoside Hydrolase |
|
|
