A genetically engineered gene fusion was constructed which encoded a nontoxic derivative of the A fragment of diphtheria toxin joined to the C180 peptide of the S1 subunit of pertussis toxin. The product of this gene fusion, termed the DTA-C180 protein, was purified from the periplasm of Escherichia coli to approximately 80% purity. The DTA-C180 protein possessed an apparent molecular weight of...

The molecular events underlying the inhibition of exocytosis by tetanus toxin were investigated in permeabilized adrenal chromaffin cells. We found that replacement of amino acid residues within the putative zinc binding domain of the tetanus toxin light chain such as of histidine (position 233) by cysteine or valine, or of glutamate (position 234) by glutamine completely abolished the effect o...

Staphylococcal enterotoxin B (SEB) and α‑toxin produced by Staphylococcus aureus (S. aureus) are important in the pathogenesis of diseases. In the present study, we investigated the effects of SEB and α‑toxin on ECV304 cells. It was identified that both SEB and α‑toxin were capable of inducing the apoptosis of ECV304 cells in a dose‑ and time‑dependent manner. In addition, SEB and α‑toxin were ...

Natural diphtheria toxin is synthesized as a single polypeptide chain that is activated by cleavage into an A- and a B-fragment, which are linked by a disulphide bond. In the present work the ability of independently translated A- and B-fragments to associate was investigated. Low amounts of A- and B-fragments synthesized in vitro were mixed under conditions that allowed formation of a disulphi...

The novel insecticidal toxin, LaIT2, was isolated from venom of the scorpion Liocheles australasiae. The amino acid sequence of LaIT2 was determined by an Edman degradation analysis and subsequent cDNA cloning. LaIT2 is composed of 59 amino acids with three disulfide bridges, and shares sequence similarity to the scorpion beta-KTx peptides.

Staphylococcus aureus produces phenol-soluble modulins (PSMs), which are amphipathic small peptides with lytic activity against mammalian cells. We previously reported that PSMα1-4 stimulate S. aureus colony spreading, the phenomenon of S. aureus colony expansion on the surface of soft agar plates, whereas δ-toxin (Hld, PSMγ) inhibits colony-spreading activity. In this study, we revealed the un...

Pertussis toxin binds target cells through the carbohydrate recognition properties of two subunits, S2 and S3, which share amino acid sequence similarity with the lectin domains of the eukaryotic selectin family. Selectins appear on inflamed endothelial cells and promote rolling of leukocytes by reversibly binding carbohydrates. S2, S3, and synthetic peptides representing their carbohydrate rec...

Small peptides isolated from the venom of animals are potential scaffolds for ion channel drug discovery. This review article mainly focuses on the computational studies that have advanced our understanding of how various toxins interfere with the function of K⁺ channels. We introduce the computational tools available for the study of toxin-channel interactions. We then discuss how these comput...

Venoms of snakes, scorpions, spiders, insects, sea anemones, and cone snails are complex mixtures of mostly peptides and small proteins that have evolved for prey capture and/or defense. These deadly animals have long fascinated scientists and the public. Early studies isolated lethal components in the search for cures and understanding of their mechanisms of action. Ion channels have emerged a...

The positions of the disulfide bonds in Cerebratulus lacteus toxin B-IV were investigated by hydrolysis of the unreduced protein with a variety of proteases. The resulting peptides were purified by gel filtration, ion exchange chromatography, and preparative paper electrophoresis and chromatography. Determination of the amino acid compositions of the cystine-containing peptides purified demonst...