4ELC: Crystal Structure Of The Catalytic Domain Of Botulinum Neurotoxin BontA C134 MUTANT WITH MTSEA MODIFIED CYS-165

Citation:
Abstract
Clostridium botulinum neurotoxin type A (BoNT/A) is one of the most potent toxins for humans and a major biothreat agent. Despite intense chemical efforts over the past 10 years to develop inhibitors of its catalytic domain (catBoNT/A), highly potent and selective inhibitors are still lacking. Recently, small inhibitors were reported to covalently modify catBoNT/A by targeting Cys(165), a residue located in the enzyme active site just above the catalytic zinc ion. However, no direct proof of Cys(165) modification was reported, and the poor accessibility of this residue in the x-ray structure of catBoNT/A raises concerns about this proposal. To clarify this issue, the functional role of Cys(165) was first assessed through a combination of site-directed mutagenesis and structural studies. These data suggested that Cys(165) is more involved in enzyme catalysis rather than in structural property. Then by peptide mass fingerprinting and x-ray crystallography, we demonstrated that a small compound containing a sulfonyl group acts as inhibitor of catBoNT/A through covalent modification of Cys(165). The crystal structure of this covalent complex offers a structural framework for developing more potent covalent inhibitors catBoNT/A. Other zinc metalloproteases can be founded in the protein database with a cysteine at a similar location, some expressed by major human pathogens; thus this work should find broader applications for developing covalent inhibitors.
PDB ID: 4ELCDownload
MMDB ID: 101998
PDB Deposition Date: 2012/4/10
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 4ELC: monomeric; determined by author and by software (PISA)
Molecular Components in 4ELC
Label Count Molecule
Protein (1 molecule)
1
Botulinum Neurotoxin a Light Chain
Molecule annotation
Chemicals (14 molecules)
1
1
2
2
3
1
4
3
5
2
6
2
7
3
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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