A DARPin promotes faster onset of botulinum neurotoxin A1 action.

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 α- and β-exosite.

A coiled-coil-based design strategy for the thermostabilization of G-protein-coupled receptors.

Structure elucidation of inactive-state GPCRs still mostly relies on X-ray crystallography. The major goal of our work was to create a new GPCR tool that would provide receptor stability and additional soluble surface for crystallization. Towards this aim, we selected the two-stranded antiparallel coiled coil as a domain fold that satisfies both criteria.

Crystal structure of the catalytic domain of botulinum neurotoxin subtype A3.

Botulinum neurotoxins (BoNTs) are among the most widely used therapeutic proteins; however, only two subtypes within the seven serotypes, BoNT/A1 and BoNT/B1, are currently used for medical and cosmetic applications. Distinct catalytic properties, substrate specificities, and duration of enzymatic activities potentially make other subtypes very attractive candidates to outperform conventional BoNTs in particular therapeutic applications. For example, BoNT/A3 has a significantly shorter duration of action than other BoNT/A subtypes.

Structural insights into the interaction of botulinum neurotoxin a with its neuronal receptor SV2C.

A dual-receptor interaction with a polysialoganglioside and synaptic vesicle glycoprotein 2 (SV2) is required for botulinum neurotoxin A (BoNT) toxicity. Here, we review what is currently known about the BoNT/A-SV2 interaction based on structural studies. Currently, five crystal structures of the receptor-binding domain (Hc) of BoNT subtypes A1 and A2 complexed to the large luminal domain (LD4) of SV2C have been determined.

The first non Clostridial botulinum-like toxin cleaves VAMP within the juxtamembrane domain.

The genome of Weissella oryzae SG25T was recently sequenced and a botulinum neurotoxin (BoNT) like gene was identified by bioinformatics methods. The typical three-domains organization of BoNTs with a N-terminal metalloprotease domain, a translocation and a cell binding domains could be identified. The BoNT family of neurotoxins is rapidly growing, but this was the first indication of the possible expression of a BoNT toxin outside the Clostridium genus.

Hsp90 is involved in the entry of clostridial neurotoxins into the cytosol of nerve terminals.

Botulinum and tetanus neurotoxins are the most toxic substances known and form the growing family of clostridial neurotoxins. They are composed of a metalloprotease light chain (L), linked via a disulfide bond to a heavy chain (H). H mediates the binding to nerve terminals and the membrane translocation of L into the cytosol where their substrates, the three SNARE proteins, are localised.

A Novel Inhibitor Prevents the Peripheral Neuroparalysis of Botulinum Neurotoxins.

Botulinum neurotoxins (BoNTs) form a large class of potent and deadly neurotoxins. Given their growing number, it is of paramount importance to discover novel inhibitors targeting common steps of their intoxication process. Recently, EGA was shown to inhibit the action of bacterial toxins and viruses exhibiting a pH-dependent translocation step in mammalian cells, by interfering with their entry route.

On the translocation of botulinum and tetanus neurotoxins across the membrane of acidic intracellular compartments.

Tetanus and botulinum neurotoxins are produced by anaerobic bacteria of the genus Clostridium and are the most poisonous toxins known, with 50% mouse lethal dose comprised within the range of 0.1-few nanograms per Kg, depending on the individual toxin. Botulinum neurotoxins are similarly toxic to humans and can therefore be considered for potential use in bioterrorism.

Diphtheria toxin conformational switching at acidic pH.

Unlabelled: Diphtheria toxin (DT), the etiological agent of the homonymous disease, like other bacterial toxins, has to undergo a dramatic structural change in order to be internalized into the cytosol, where it finally performs its function. The molecular mechanism of toxin transit across the membrane is not well known, but the available experimental evidence indicates that one of the three domains of the toxin, called the central α-helical domain, inserts into the lipid bilayer, so favoring the translocation of the catalytic domain. This process is driven by the acidic pH of the endosomal lumen.