This looked interesting -
newscientist.com
"...Now Laszlo Otvos from the Wistar Institute in Philadelphia and his colleagues have isolated a group of insect peptides which target specific molecules inside bacterial cells.
The peptide, present in the European sap-sucking insect Pyrrhocoris apterus, is called pyrrhocoricin. The researchers identified the protein it targets by attaching the peptide to a "hook" molecule called biotin. They mixed the biotin-peptide with bacterial cells, then used beads coated with an antibody against biotin to pull it back out of the cells again, this time bound to its mystery target.
The research will appear in the next issue of Biochemistry. "It's a very elegant piece of biochemistry," says Ian Chopra, head of the Antimicrobial Research Centre at Leeds University.
The target turned out to be a "heat shock protein" called DnaK, which re-folds malformed proteins back into shape. DnaK is an essential protein in the cell, and when it is inactivated by the peptide, the bacterium dies. All species have their own version of DnaK, but the researchers showed that the human equivalent, called Hsp70, is different enough not to be affected by the peptides--so insect DnaKs could be safe to use as drugs...
"Specific antibiotics would help in the fight against resistance, but the approach would need to go hand in hand with much more rapid and improved diagnostic methods," he says...."
Although there are problems -
wistar.upenn.edu
"...In our attempts to develop a drug lead, we tried to stabilize pyrrhocoricin. The resistance of the peptide to aminopeptidase cleavage could be increased by N-terminal acetylation, but the same modification resulted in a complete loss of biological activity..." |
