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The exfoliative toxins (ETs) cause staphylococcal scalded skin syndrome, a disease characterized by specific separation of layers of the skin. Research has shown that the toxins act as serin proteases, though the specific substrate and mode of action are not known for certain. The crystal structure of exfoliative toxin A (ETA) has been found previously to be similar to that of chymotrypsin-like serine proteases. The 2.4 angstrom resolution crystal structure of the other exfoliative toxin, ETB, which is 40% identical to ETA.

Verotoxins are a class of bacterial toxins whose morphology constitutes an enzymatic A subunit where the toxic activity resides and is linked to a B oligomer that binds to specific cell-surface carbohydrate receptors. The solution structure of this carbohydrate B subunit of verotoxin VT-1 from the enterohemmorrhagic Escherichia coli is determined in relation to the trimethylsilylethyl derivative of the trisaccharide moiety of Gb3. The solution structure was obtained using nuclear magnetic resonance methods and is described.

The three-dimensional structures of the cyclic cyanobacterial heptapeptide toxin microcystin-LR was characterized using nuclear magnetic resonance spectroscopy in aqueous and dimethyl sulfoxide (DMSO)/water solutions. Spatial arrangement was further studied by simulated annealing and molecular dynamics calculations. In solution, microcystin-LR predicted a single saddle-shaped backbone conformation with the flat part consisting of the residues Adda5-Glu6-Mdha7. The side segments of Arg4 and the remote portion of Adda5 are described to be pliable with no discernible structures.

Recombination of two delta-toxins from Bacillus thuringiensis, CryIAa and CryIAc, by reciprocal exchange of specificity regions resulted in proteins susceptible to proteolyticcleavage and reduced insecticidal potency. The instability of the recombinant toxin structure can be suppressed by introducing a second mutation in defined regions of the gene for the original recombinant CryIAa gene.

The activation and activation of aerolysin from the protoxin form were analyzed using several spectroscopic techniques. The sites for trypsin and chymotrypsin cleavage were identified. Trypsin-mediated proteolytic modification does not produce appreciable alteration in the toxin's secondary or tertiary conformation, however, there is an alteration in the spatial orientation of tryptophan residues due to the exposure of a hydrophobic region. The oligomerization of aerolysin molecules activated by trypsin was also investigated.