We recently showed that the gamma-subunit of Kluyveromyces lactis killer toxin (gamma-toxin) is a tRNA endonuclease that cleaves tRNA(mcm5s2UUC Glu), tRNA(mcm5s2UUU Lys), and tRNA(mcm5s2UUG Gln) 3' of the wobble nucleoside 5-methoxycarbonylmethyl-2-thiouridine (mcm(5)s(2)U). The 5-methoxycarbonylmethyl (mcm(5)) side chain was important for efficient cleavage by gamma-toxin, and defects in mcm(5...

Staphylococcus aureus alpha-toxin is a membrane-damaging exoprotein that oligomerizes to form transmembrane pores. Chemical modification of histidines with diethylpyrocarbonate has been shown to reduce the hemolytic activity of alpha-toxin, suggesting that one or more of the histidine residues is important for toxin function. To individually assess the functional importance of each of the four ...

In human neutrophils, the synthetic lipopeptide, N-palmitoyl-S-[2,3-bis(palmitoyloxy-(2RS)propyl]-(~)-cysteiny1-(S)-seryl-(S)-lysyl-(S)-lysyl-(S)-lysyl-(~-lysine [Pam,CysSer(Lys),], activates NADPH-oxidase catalyzed superoxide (0;) formation through pertussis-toxin-sensitive and pertussis-toxin-insensitive mechanisms (Seifert, R., Schultz, G., Richter-Freund, M., Metzger, J ., Wiesmuller, K.-H....

Clostridium perfringens iota-toxin consists of two separate proteins identified as a cell binding protein, iota b (Ib), which forms high-molecular-weight complexes on cells generating Na(+)/K(+)-permeable pores through which iota a (Ia), an ADP-ribosyltransferase, presumably enters the cytosol. Identity of the cell receptor and membrane domains involved in Ib binding, oligomer formation, and in...

Staphylococcal alpha-toxin was radiolabeled to high specific radioactivity (1,500-3,000 Ci/mmol) under retention of its hemolytic activity. Binding studies with susceptible rabbit erythrocytes and highly resistant human erythrocytes revealed that binding of alpha-toxin to target cells can occur via two different mechanisms. Binding of alpha-toxin to rabbit erythrocytes initially involves specif...

The ability of a strain of Clostridium tetani to produce toxin is conventionally determined by measuring the Lf titer of the culture supernatant fluid after lysis is completed sometime after the third or fourth day of incubation. Although the flocculation procedure has been repeatedly found useful in the development of a suitable nutritional background for toxin production (Mueller and 1liller,...

Interaction between bacterial toxins and cellular surface receptors is an important component of the host-pathogen interaction. Anthrax toxin protective antigen (PA) binds to the cell surface receptor, enters the cell through receptor-mediated endocytosis, and forms a pore on the endosomal membrane that translocates toxin enzymes into the cytosol of the host cell. As the major receptor for anth...

Toxin complexes from Xenorhabdus and Photorhabdus spp. bacteria represent novel insecticidal proteins. We purified a native toxin complex (toxin complex 1) from Xenorhabdus nematophilus. The toxin complex is composed of three different proteins, XptA2, XptB1, and XptC1, representing products from class A, B, and C toxin complex genes, respectively. We showed that recombinant XptA2 and co-produc...

The biochemical characteristics of specific receptor molecules for diphtheria toxin on the surface of two toxin-sensitive cell lines (Vero and BS-C-1) were examined. Diphtheria toxin was found to bind to a number of different proteins in Nonidet P-40 solubilized extracts of 125I-labeled cells. In contrast, permitting diphtheria toxin to bind first to labeled intact cells, which were subsequentl...