3bta

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CRYSTAL STRUCTURE OF BOTULINUM NEUROTOXIN SEROTYPE A

Structural highlights

3bta is a 1 chain structure with sequence from Clostridium botulinum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3.2Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

BXA1_CLOBH Inhibits acetylcholine release. The botulinum toxin binds with high affinity to peripheral neuronal presynaptic membrane to the secretory vesicle protein SV2. It binds directly to the largest luminal loop of SV2A, SV2B and SV2C. It is then internalized by receptor-mediated endocytosis. The C-terminus of the heavy chain (H) is responsible for the adherence of the toxin to the cell surface while the N-terminus mediates transport of the light chain from the endocytic vesicle to the cytosol. After translocation, the light chain (L) hydrolyzes the 197-Gln-|-Arg-198 bond in SNAP-25, thereby blocking neurotransmitter release. Inhibition of acetylcholine release results in flaccid paralysis, with frequent heart or respiratory failure.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Botulinum neurotoxin type A (BoNT/A) is the potent disease agent in botulism, a potential biological weapon and an effective therapeutic drug for involuntary muscle disorders. The crystal structure of the entire 1,285 amino acid di-chain neurotoxin was determined at 3.3 A resolution. The structure reveals that the translocation domain contains a central pair of alpha-helices 105 A long and a approximately 50 residue loop or belt that wraps around the catalytic domain. This belt partially occludes a large channel leading to a buried, negative active site--a feature that calls for radically different inhibitor design strategies from those currently used. The fold of the translocation domain suggests a mechanism of pore formation different from other toxins. Lastly, the toxin appears as a hybrid of varied structural motifs and suggests a modular assembly of functional subunits to yield pathogenesis.

Crystal structure of botulinum neurotoxin type A and implications for toxicity.,Lacy DB, Tepp W, Cohen AC, DasGupta BR, Stevens RC Nat Struct Biol. 1998 Oct;5(10):898-902. PMID:9783750^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Lacy DB, Tepp W, Cohen AC, DasGupta BR, Stevens RC. Crystal structure of botulinum neurotoxin type A and implications for toxicity. Nat Struct Biol. 1998 Oct;5(10):898-902. PMID:9783750 doi:10.1038/2338