View source for 8hkh


==Crystal structure of the LC/A1-DARPin18 complex==
<StructureSection load='8hkh' size='340' side='right'caption='[[8hkh]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8hkh]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Clostridium_botulinum Clostridium botulinum] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8HKH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8HKH FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8hkh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8hkh OCA], [https://pdbe.org/8hkh PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8hkh RCSB], [https://www.ebi.ac.uk/pdbsum/8hkh PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8hkh ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BXA1_CLOBH 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.
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== Publication Abstract from PubMed ==
In this study, we characterize Designed Ankyrin Repeat Proteins (DARPins) as investigative tools to probe botulinum neurotoxin A1 (BoNT/A1) structure and function. We identify DARPin-F5 that completely blocks SNAP25 substrate cleavage by BoNT/A1 in vitro. X-ray crystallography reveals that DARPin-F5 inhibits BoNT/A1 activity by interacting with a substrate-binding region between the alpha- and beta-exosite. This DARPin does not block substrate cleavage of BoNT/A3, indicating that DARPin-F5 is a subtype-specific inhibitor. BoNT/A1 Glu-171 plays a critical role in the interaction with DARPin-F5 and its mutation to Asp, the residue found in BoNT/A3, results in a loss of inhibition of substrate cleavage. In contrast to the in vitro results, DARPin-F5 promotes faster substrate cleavage of BoNT/A1 in primary neurons and muscle tissue by increasing toxin translocation. Our findings could have important implications for the application of BoNT/A1 in therapeutic areas requiring faster onset of toxin action combined with long persistence.

A DARPin promotes faster onset of botulinum neurotoxin A1 action.,Leka O, Wu Y, Zanetti G, Furler S, Reinberg T, Marinho J, Schaefer JV, Pluckthun A, Li X, Pirazzini M, Kammerer RA Nat Commun. 2023 Dec 18;14(1):8317. doi: 10.1038/s41467-023-44102-4. PMID:38110403<ref>PMID:38110403</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 8hkh" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Clostridium botulinum]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Kammerer R]]
[[Category: Leka O]]
[[Category: Wu Y]]