Bis-imidazoles as Molecular Probes for Peripheral Sites of the Zinc Endopeptidase of Botulinum Neurotoxin Serotype A
Abstract
Botulinum neurotoxin serotype A (BoNTA) is highly toxic, and its antidote is currently unavailable. The essential light-chain subunit of BoNTA is a zinc endopeptidase that can be used as a target for developing antidotes. However, the development of high-affinity, small-molecule inhibitors of the endopeptidase is as challenging as the development of small-molecule inhibitors of protein-protein complexation, This is because the polypeptide substrate wraps around the circumference of the endopeptidase upon binding, thereby constituting an unusally large substrate-enzyme interface of 4840 . To overcome the large interface problem, we propose using the zinc-coordination and bivalence approaches to design inhibitors of BoNTA. Here we report the development of alkylene-linked bis-imidizoles that inhibit the endopeptidase in a two-site binding mode. The bis-imidazole tethered with 13 methylene groups, the most potent of the alkylene-linked dimers, showed a 61% inhibition of the zinc endopeptidase of BoNTA at a concentration of 100 M. The results demonstrate the presence of a peripheral binding site for an imiazolium group at the rim of the BoNTA active-site cleft. This peripheral site enables the use of the bivalence approach to improve our previously reported small-molecule inhibitors that were developed according the zinc-coordination. approach.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 02, 2006
- Accession Number
- ADA452689
Entities
People
- Charles B. Millard
- Isidro Merino
- James J. Schmidt
- Jason D. Thompson
- Yuan-Ping Pang