PhD thesis of Jitka Rihakova (2006-2009)

This research project has several goals. First, a major goal is to determine the structure function relationship of divercin V41, and to understand its mode of action. Then the second one is the heterologous expression of divercin V41 in Lactococus lactis. To achieve these scientific objectives, several molecular biology methods, site-directed mutagenis, circular dichroism, spectroscopy, biochemistry méthods have been used and several collaborations have been established. In the study of structure and function relationship of Dvn RV41, eight derivative peptides were produced by site directed mutagenesis and each derivative peptide was modified in one specific amino acid. The activity of all variants against Listeria monocytogenes EGDe and Enterococcus faecalis JH2-2 in vitro appeared to be decreased, as compared to DvnRV41. The decrease in activity of four variants was shown also in a murin model against Listeria monocytogenes EGDe. The results showed that the central region of DvnRV41 was necessary for the antibacterial activity and was important for the correct spatial position of DvnRV41 for its mechanism of action.