Innate antibacterial ability scrutinised
6 June 2008
The bonds that bind tiny fragments of the immune system called b-defensins have been scrutinised to find out if they are required for the molecules’ powerful properties. The results show that the antimicrobial activity of b-defensins can be separated from their ability to attract immune cells. In addition these properties have not been found to be dependent on bonds within the molecule and can still function in their absence.
Defensins are small protein molecules called peptides that are made up of short chains of amino acids. They are thought to be important in the first response of a person exposed to microorganisms like bacteria or viruses. They are able to quickly kill bacteria, viruses or yeast and can also attract specialised immune cells to the site of infection. Their action is non-specific and broad ranging which helps stop healthy people from being affected by the large number of microorganisms that are all around us.
Dr Julia Dorin of the MRC Human Genetics Unit who led the study in collaboration with Edinburgh University School of Chemistry said: ‘‘It is important that the structure-function relationships of these peptides are determined as they have great therapeutic potential. As well as antimicrobial abilities, defensins are chemoattractant, this means they attract specialised immune cells to move towards them.’’
‘‘In this study we have discovered that the anti-microbial and chemoattractant properties of b-defensins can be separated, this new knowledge could help not only further understanding of how defensins provide natural defence against bacterial infection but also in the design of therapeutic agents.’’
The research results are published in the Journal of Biological Chemistry.
Original research paper: ‘Analysis and separation of residues important for the chemoattractant and antimicrobial activities of ß-defensin 3’ is published in Journal of Biological Chemistry.
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