The role of bacterial carbohydrate protective coating against antimicrobial peptides

The lack of antibiotics available to fight drug resistant bacteria is posing a serious threat to world health and is possible that the next pandemic will be caused by a bacterial pathogen rather than a virus. We can use neutrons to look at the main defence barrier of Gram-negative bacteria in great detail to visualise the effects of antibiotics on its complex asymmetric structure. In this proposal we wish to gain a deeper understanding of the effects of two antimicrobials, polymyxin B and alpha-purothionin on a realistic model of the bacterial cell envelope of pathogens. We have already looked at the effects of these antimicrobials on membranes mimicking the surface of laboratory-adapted bacteria and we wish now to compare what we have learned so far with the more complex and robust membrane of pathogens which contains an additional layer of protection formed of long carbohydrates