Kristiansen Group

Description of Research Group

We are involved in structure function studies of ribosomal and none ribosomal produced antimicrobial peptides and their antimicrobial function/interactions. We use CD and NMR spectroscopy to characterize the structures in combination with activity measurements on site specific mutants and molecular dynamics to determine the mode of action.

Large portion of our research has been directed at determine the mode of action of antimicrobial bacteriocins ribosomally produced by lactic acid bacteria (LAB). Recent results indicate that many of the bacteriocins, if
not all LAB bacteriocins, exert their antimicrobial activity by a receptor-mediated mode-of-action. In contrast, less potent eukaryotic AMPs appear in many cases to bind in a non-chiral manner to bacterial
membrane lipids and at sufficiently high peptide concentrations disrupt the membrane. The receptor mediated mode-of-action apparently involves so-called “membrane catalysis” These peptides are typically
unstructured in buffer solution but are drawn to the membrane through electro static interactions, does become structured and positioned so that it may interact with membrane bound receptor. Recently we also started working on none ribosomally produced peptides with antimicrobial activity against gram positive bacteria such as MRSA. These are peptides produced by a large complex multi domain machinery catalyzing the production of a diverse family of natural products These natural products have several applications both by the cells producing them and in medical science as antibiotics and other medically important compounds.

Technology, expertise and equipment

Broad background in NMR spectroscopy in the characterization of peptide protein and peptide membrane interaction applying of both liquid and solid stat NMR on biological samples/model system. The NMR is supported with CD spectroscopy, analysis of activity of mutants and Molecular Dynamics
to determine the mode of action.