The lab I’m a part of does a lot of work with anti microbial peptides whose mechanism of action is either permeabilizing the membrane (effectively poking holes) of the target cells or translocating through the membrane into the cell and into the nucleus to interact with DNA. I’ve wondered how safe these peptides would be for use considering that both bacteria and human cells have membranes but understanding the composition of the membranes of the two kinds of cells has explained why. It turns out that though most bacterial membranes are composed of neutral phosphatidylethanolamine, they also contain many liposaccharides which give them a net negative charge. Human cell membrane contain varied lipids and charge is not negative like the bacteria’s. As such, the polycationic anti microbial peptides can target the negatively charged bacterial membranes but leave the human ones intact.
4 Responses to Anti microbial peptides
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That’s really interesting. I know that gram positive and gram negative bacteria have significantly different membrane compositions. Do you know if the same type of anti microbials will work on both types of bacteria?
That’s awesome, Mwangala. It cool to use what we know about the differences between human and bacterial composition to tweak the drugs we use to be selectively only acting with one or the other. I just wrote above about how azithromycin block protein synthesis in bacteria by basically inserting itself like a plug into bacterial ribosomes, but I’m still curious to find specifically why it doesn’t do the same to our ribosomes!
(Wow typos haha- I need sleep!)
Alyssa, I’m not completely sure but my guess is that gram positive and negative bacteria have membranes that are more similar to each other than they are to human membranes so selectivity still should work. I would think that the efficient would differ though.