Kristensen and Nissen-Meyer group
The Peptide Group is involved in research on antibacterial peptides produced by lactic acid bacteria.
About the group
he Peptide Group is involved in research on antibacterial peptides produced by lactic acid bacteria. These peptides (often referred to as peptide bacteriocins) are of great interest because they are produced by “food grade” bacteria and might consequently be utilized as relatively safe agents for preventing growth of pathogenic/undesirable microorganisms. Our research focus has in recent years especially been on elucidating the mode-of-action and three-dimensional structure of peptides that group members have previously isolated, sequenced and genetically characterized. Some of the peptides have been shown to kill bacteria by a receptor-mediated mechanism, which entails that the peptides bind to specific membrane proteins, and thereby cause membrane-leakage and cell death. Through this receptor-mediated mode-of-action, the peptides show antibacterial activity at nanomolar to picomolar concentrations. The structure and structure-function relationships of these peptides have been analyzed using NMR-spectroscopy and site-directed in vitro mutagenesis. These last years, the receptors of several of these peptides have been identified by the use of whole-genome sequencing of spontaneous mutants of sensitive cells that have gained resistance to the peptides. Moreover, heterologous expression of these receptors in non-sensitive bacteria was shown to rend the bacteria sensitive to the peptides. The approach of whole genome sequencing of peptide resistant mutants combined with heterologous expression should be a widely applicable method for identification of receptors also for other peptide ligands.