It used to be that antibiotics could be trusted to rid the body of a host of bacterial diseases. Today, however, emerging strains of antibiotic-resistant bacteria are speeding ahead, threatening to make existing drugs obsolete. Now, researchers at the Weizmann Institute of Science have developed an original approach that may lead to a radically new way of treating bacterial infections.
Insects, frogs and, as was recently discovered, humans, have a clever first line of defense against bacterial infections. This defense consists of peptides, or protein fragments, that zap the bacteria, literally spilling their "guts." Prof. Yechiel Shai of the Biological Chemistry Department and his team studied the way these peptides work and found that peptide strategy is as ingenious as it is simple: similar to a detergent or soap that dissolves fatty stains, peptides attach themselves to a bacterium and dissolve a portion of its membrane, which is made of a fatty substance. Once its membrane is punctured, the contents of the bacterium spill out and it dies on the spot.
Having characterized this bacteria-bashing mechanism, Shai's team went on to synthesize novel antimicrobial peptides that are more stable and long-lasting than the natural ones. They hope that these peptides will become the basis for potent antibacterial drugs. Because the new peptide materials kill bacteria instantly, it's unlikely that germs will get a chance to develop resistance against the medication.
Another major advantage of the new peptides is their simplicity. In contrast to antibiotics, which must perform the complicated task of penetrating bacteria and interfering with their functioning, the peptides simply attach themselves to bacterial membranes.
The Weizmann scientists have discovered that peptide
attachment depends primarily on chemical composition, not
structure. As a result, a synthetic peptide does not require a
particularly good fit to be effective. This simpli
Contact: Julie Osler
American Committee for the Weizmann Institute of Science