A Potent Peptidomimetic Inhibitor of Botulinum Neurotoxin Serotype A Has a Very Different Conformation than SNAP-25 Substrate

Botulinum neurotoxin serotype A is the most lethal of all known toxins. Here, we report the crystal structure, along with SAR data, of the zinc metalloprotease domain of BoNT/A bound to a potent peptidomimetic inhibitor (Ki = 41 nM) that resembles the local sequence of the SNAP-25 substrate. Surpris...

Full description

Saved in:
Bibliographic Details
Published in:Structure (London) 2008-10, Vol.16 (10), p.1588-1597
Main Authors: Zuniga, Jorge E., Schmidt, James J., Fenn, Timothy, Burnett, James C., Araç, Demet, Gussio, Rick, Stafford, Robert G., Badie, Shirin S., Bavari, Sina, Brunger, Axel T.
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Binding Sites
Biomimetics
Botulinum Toxins, Type A - antagonists & inhibitors
Botulinum Toxins, Type A - chemistry
Botulinum Toxins, Type A - metabolism
Drug Evaluation, Preclinical
Models, Biological
Models, Molecular
Molecular Sequence Data
MOLNEURO
Peptide Fragments - chemistry
Peptide Fragments - metabolism
Peptide Fragments - pharmacology
Protein Binding
Protein Conformation
PROTEINS
Substrate Specificity
Synaptosomal-Associated Protein 25 - chemistry
Synaptosomal-Associated Protein 25 - metabolism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Botulinum neurotoxin serotype A is the most lethal of all known toxins. Here, we report the crystal structure, along with SAR data, of the zinc metalloprotease domain of BoNT/A bound to a potent peptidomimetic inhibitor (Ki = 41 nM) that resembles the local sequence of the SNAP-25 substrate. Surprisingly, the inhibitor adopts a helical conformation around the cleavage site, in contrast to the extended conformation of the native substrate. The backbone of the inhibitor's P1 residue displaces the putative catalytic water molecule and concomitantly interacts with the “proton shuttle” E224. This mechanism of inhibition is aided by residue contacts in the conserved S1′ pocket of the substrate binding cleft and by the induction of new hydrophobic pockets, which are not present in the apo form, especially for the P2′ residue of the inhibitor. Our inhibitor is specific for BoNT/A as it does not inhibit other BoNT serotypes or thermolysin.
ISSN:0969-2126
1878-4186
DOI:10.1016/j.str.2008.07.011