Activity of botulinum neurotoxin X and its structure when shielded by a non-toxic non-hemagglutinin protein.

Botulinum neurotoxins (BoNTs) are the most potent toxins known and are used to treat an increasing number of medical disorders. All BoNTs are naturally co-expressed with a protective partner protein (NTNH) with which they form a 300 kDa complex, to resist acidic and proteolytic attack from the digestive tract. We have previously identified a new botulinum neurotoxin serotype, BoNT/X, that has unique and therapeutically attractive properties.

Structural and functional insight into the interaction of Clostridioides difficile toxin B and FZD.

The G protein-coupled receptors of the Frizzled (FZD) family, in particular FZD, are receptors that are exploited by Clostridioides difficile toxin B (TcdB), the major virulence factor responsible for pathogenesis associated with Clostridioides difficile infection. We employ a live-cell assay examining the affinity between full-length FZDs and TcdB. Moreover, we present cryoelectron microscopy structures of TcdB alone and in complex with full-length FZD, which reveal that large structural rearrangements of the combined repetitive polypeptide domain are required for interaction with FZDs and other TcdB receptors, constituting a first step for receptor recognition.

Structure and activity of botulinum neurotoxin X.

Botulinum neurotoxins (BoNTs) are the most potent toxins known and are used to treat an increasing number of medical disorders. All BoNTs are naturally co-expressed with a protective partner protein (NTNH) with which they form a 300 kDa complex, to resist acidic and proteolytic attack from the digestive tract. We have previously identified a new botulinum neurotoxin serotype, BoNT/X, that has unique and therapeutically attractive properties.

Optimization of N-Piperidinyl-Benzimidazolone Derivatives as Potent and Selective Inhibitors of 8-Oxo-Guanine DNA Glycosylase 1.

8-oxo Guanine DNA Glycosylase 1 is the initiating enzyme within base excision repair and removes oxidized guanines from damaged DNA. Since unrepaired 8-oxoG could lead to G : C→T : A transversion, base removal is of utmost importance for cells to ensure genomic integrity. For cells with elevated levels of reactive oxygen species this dependency is further increased.

Small-molecule activation of OGG1 increases oxidative DNA damage repair by gaining a new function.

Oxidative DNA damage is recognized by 8-oxoguanine (8-oxoG) DNA glycosylase 1 (OGG1), which excises 8-oxoG, leaving a substrate for apurinic endonuclease 1 (APE1) and initiating repair. Here, we describe a small molecule (TH10785) that interacts with the phenylalanine-319 and glycine-42 amino acids of OGG1, increases the enzyme activity 10-fold, and generates a previously undescribed β,δ-lyase enzymatic function. TH10785 controls the catalytic activity mediated by a nitrogen base within its molecular structure.

Structural Analysis of Botulinum Neurotoxins Type B and E by Cryo-EM.

Botulinum neurotoxins (BoNTs) are the causative agents of a potentially lethal paralytic disease targeting cholinergic nerve terminals. Multiple BoNT serotypes exist, with types A, B and E being the main cause of human botulism. Their extreme toxicity has been exploited for cosmetic and therapeutic uses to treat a wide range of neuromuscular disorders.

Mechanism of Ganglioside Receptor Recognition by Botulinum Neurotoxin Serotype E.

The botulinum neurotoxins are potent molecules that are not only responsible for the lethal paralytic disease botulism, but have also been harnessed for therapeutic uses in the treatment of an increasing number of chronic neurological and neuromuscular disorders, in addition to cosmetic applications. The toxins act at the cholinergic nerve terminals thanks to an efficient and specific mechanism of cell recognition which is based on a dual receptor system that involves gangliosides and protein receptors. Binding to surface-anchored gangliosides is the first essential step in this process.

Targeting OGG1 arrests cancer cell proliferation by inducing replication stress.

Altered oncogene expression in cancer cells causes loss of redox homeostasis resulting in oxidative DNA damage, e.g. 8-oxoguanine (8-oxoG), repaired by base excision repair (BER).

Structural and Biochemical Characterization of Botulinum Neurotoxin Subtype B2 Binding to Its Receptors.

Botulinum neurotoxins (BoNTs) can be used therapeutically to treat a wide range of neuromuscular and neurological conditions. A collection of natural BoNT variants exists which can be classified into serologically distinct serotypes (BoNT/B), and further divided into subtypes (BoNT/B1, B2, …). BoNT subtypes share a high degree of sequence identity within the same serotype yet can display large variation in toxicity.

Crystal Structure of Exotoxin A from Pathogenic Species.

exotoxin A (AE) is a bacterial virulence factor recently discovered in a clinical case of necrotising fasciitis caused by the flesh-eating . Here, database mining shows that AE is present in the genome of several emerging pathogenic species. The X-ray crystal structure of AE was solved at 2.

Characterization of a membrane binding loop leads to engineering botulinum neurotoxin B with improved therapeutic efficacy.

Botulinum neurotoxins (BoNTs) are a family of bacterial toxins with seven major serotypes (BoNT/A-G). The ability of these toxins to target and bind to motor nerve terminals is a key factor determining their potency and efficacy. Among these toxins, BoNT/B is one of the two types approved for medical and cosmetic uses.

Structural basis for the interaction of the chaperone Cbp3 with newly synthesized cytochrome during mitochondrial respiratory chain assembly.

Assembly of the mitochondrial respiratory chain requires the coordinated synthesis of mitochondrial and nuclear encoded subunits, redox co-factor acquisition, and correct joining of the subunits to form functional complexes. The conserved Cbp3-Cbp6 chaperone complex binds newly synthesized cytochrome and supports the ordered acquisition of the heme co-factors. Moreover, it functions as a translational activator by interacting with the mitoribosome.

A neurotoxin that specifically targets Anopheles mosquitoes.

Clostridial neurotoxins, including tetanus and botulinum neurotoxins, generally target vertebrates. We show here that this family of toxins has a much broader host spectrum, by identifying PMP1, a clostridial-like neurotoxin that selectively targets anopheline mosquitoes. Isolation of PMP1 from Paraclostridium bifermentans strains collected in anopheline endemic areas on two continents indicates it is widely distributed.

Crystal structure of the catalytic domain of the Weissella oryzae botulinum-like toxin.

Botulinum neurotoxins (BoNTs) are the most potent toxins known. So far, eight serotypes have been identified that all act as zinc-dependent endopeptidases targeting SNARE proteins and inhibiting the release of neurotransmitters. Recently, the first botulinum toxin-like protein was identified outside the Clostridial genus, designated BoNT/Wo in the genome of Weissella oryzae.

Engineered botulinum neurotoxin B with improved binding to human receptors has enhanced efficacy in preclinical models.

Although botulinum neurotoxin serotype A (BoNT/A) products are common treatments for various disorders, there is only one commercial BoNT/B product, whose low potency, likely stemming from low affinity toward its human receptor synaptotagmin 2 (hSyt2), has limited its therapeutic usefulness. We express and characterize two full-length recombinant BoNT/B1 proteins containing designed mutations E1191M/S1199Y (rBoNT/B1) and E1191Q/S1199W (rBoNT/B1) that enhance binding to hSyt2. In preclinical models including human-induced pluripotent stem cell neurons and a humanized transgenic mouse, this increased hSyt2 affinity results in high potency, comparable to that of BoNT/A.

Small-molecule inhibitor of OGG1 suppresses proinflammatory gene expression and inflammation.

The onset of inflammation is associated with reactive oxygen species and oxidative damage to macromolecules like 7,8-dihydro-8-oxoguanine (8-oxoG) in DNA. Because 8-oxoguanine DNA glycosylase 1 (OGG1) binds 8-oxoG and because -deficient mice are resistant to acute and systemic inflammation, we hypothesized that OGG1 inhibition may represent a strategy for the prevention and treatment of inflammation. We developed TH5487, a selective active-site inhibitor of OGG1, which hampers OGG1 binding to and repair of 8-oxoG and which is well tolerated by mice.

Botulinum and Tetanus Neurotoxins.

Botulinum neurotoxins (BoNTs) and tetanus neurotoxin (TeNT) are the most potent toxins known and cause botulism and tetanus, respectively. BoNTs are also widely utilized as therapeutic toxins. They contain three functional domains responsible for receptor-binding, membrane translocation, and proteolytic cleavage of host proteins required for synaptic vesicle exocytosis.

Crystal Structure of Botulinum Neurotoxin A2 in Complex with the Human Protein Receptor SV2C Reveals Plasticity in Receptor Binding.

Botulinum neurotoxins (BoNTs) are a family of highly dangerous bacterial toxins, with seven major serotypes (BoNT/A-G). Members of BoNTs, BoNT/A1 and BoNT/B1, have been utilized to treat an increasing number of medical conditions. The clinical trials are ongoing for BoNT/A2, another subtype of BoNT/A, which showed promising therapeutic properties.

Structural characterisation of the catalytic domain of botulinum neurotoxin X - high activity and unique substrate specificity.

Botulinum neurotoxins (BoNTs) are among the most potent toxins known and are also used to treat an increasing number of medical disorders. There are seven well-established serotypes (BoNT/A-G), which all act as zinc-dependent endopeptidases targeting specific members of the SNARE proteins required for synaptic vesicle exocytosis in neurons. A new toxin serotype, BoNT/X, was recently identified.

Identification of a Botulinum Neurotoxin-like Toxin in a Commensal Strain of Enterococcus faecium.

Botulinum neurotoxins (BoNTs), produced by various Clostridium strains, are a family of potent bacterial toxins and potential bioterrorism agents. Here we report that an Enterococcus faecium strain isolated from cow feces carries a BoNT-like toxin, designated BoNT/En. It cleaves both VAMP2 and SNAP-25, proteins that mediate synaptic vesicle exocytosis in neurons, at sites distinct from known BoNT cleavage sites on these two proteins.

Mechanism of Peptide Binding and Cleavage by the Human Mitochondrial Peptidase Neurolysin.

Proteolysis plays an important role in mitochondrial biogenesis, from the processing of newly imported precursor proteins to the degradation of mitochondrial targeting peptides. Disruption of peptide degradation activity in yeast, plant and mammalian mitochondria is known to have deleterious consequences for organism physiology, highlighting the important role of mitochondrial peptidases. In the present work, we show that the human mitochondrial peptidase neurolysin (hNLN) can degrade mitochondrial presequence peptides as well as other fragments up to 19 amino acids long.

Identification and characterization of a novel botulinum neurotoxin.

Botulinum neurotoxins are known to have seven serotypes (BoNT/A-G). Here we report a new BoNT serotype, tentatively named BoNT/X, which has the lowest sequence identity with other BoNTs and is not recognized by antisera against known BoNTs. Similar to BoNT/B/D/F/G, BoNT/X cleaves vesicle-associated membrane proteins (VAMP) 1, 2 and 3, but at a novel site (Arg66-Ala67 in VAMP2).

The structure of the tetanus toxin reveals pH-mediated domain dynamics.

The tetanus neurotoxin (TeNT) is a highly potent toxin produced by that inhibits neurotransmission of inhibitory interneurons, causing spastic paralysis in the tetanus disease. TeNT differs from the other clostridial neurotoxins by its unique ability to target the central nervous system by retrograde axonal transport. The crystal structure of the tetanus toxin reveals a "closed" domain arrangement stabilised by two disulphide bridges, and the molecular details of the toxin's interaction with its polysaccharide receptor.

Glycans Confer Specificity to the Recognition of Ganglioside Receptors by Botulinum Neurotoxin A.

The highly poisonous botulinum neurotoxins, produced by the bacterium Clostridium botulinum, act on their hosts by a high-affinity association to two receptors on neuronal cell surfaces as the first step of invasion. The glycan motifs of gangliosides serve as initial coreceptors for these protein complexes, whereby a membrane protein receptor is bound. Herein we set out to characterize the carbohydrate minimal binding epitope of the botulinum neurotoxin serotype A.

Crystal structure of a peptidyl-dipeptidase K-26-DCP from Actinomycete in complex with its natural inhibitor.

Unlabelled: Several soil-derived Actinobacteria produce secondary metabolites that are proven specific and potent inhibitors of the human angiotensin-I-converting enzyme (ACE), a key target for the modulation of hypertension through its role in the renin-angiotensin-aldosterone system. K-26-DCP is a zinc dipeptidyl carboxypeptidase (DCP) produced by Astrosporangium hypotensionis, and an ancestral homologue of ACE. Here we report the high-resolution crystal structures of K-26-DCP and of its complex with the natural microbial tripeptide product K-26.