Delta-toxin, unlike melittin, has only hemolytic activity and no antimicrobial activity: rationalization of this specific biological activity.
The antimicrobial activity of a synthetic peptide corresponding to delta-hemolysin had been examined. The peptide did not exhibit antimicrobial activity against gram negative and gram positive micro-organisms unlike other hemolytic peptides like melittin. This lack of antibacterial activity arises due to the inability of delta-hemolysin to perturb the negatively charged bacterial cell surface and permeabilize the bacterial plasma membrane. However, the red blood cell surface has a structure considerably different from bacteria and does not act as a barrier to molecules reaching the lipid membrane. Hence delta-toxin can lyse erythrocytes. Thus, the specificity in biological activity has been rationalized in terms of differences in the interaction of the toxin with the bacterial and red blood cell surfaces.
Dhople
V M
VM
Centre for Cellular and Molecular Biology, Hyderabad, India.
Nagaraj
R
R
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects*; D001426:Bacterial Proteins / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects; D006460:Hemolysin Proteins / Q000378:metabolism / Q000494:pharmacology*; D006461:Hemolysis / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D013211:Staphylococcus aureus / Q000187:drug effects
D001426:Bacterial Proteins; D006460:Hemolysin Proteins; C025994:delta hemolysin protein, Staphylococcus aureus