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High-affinity iron binding

Posted on 11 May 2016

High-affinity iron binding in Campylobacter jejuni, the most common cause of food poisoning in the UK

Researchers in York have found that a key protein within the iron uptake system of a pathogen can scavenge the fragments of siderophores made by other bacteria to gain an advantage in the competition for essential iron.

Pathogenic bacteria have evolved to synthesise molecules that enable them to acquire essential iron from their host. These siderophores display a remarkably high affinity and selectivity for iron(III).

To be competitive, many bacteria rely on the production of large siderophores with six iron-binding sites, such as the siderophore enterobactin. However, a number of species, including the food-borne pathogen Campylobacter jejuni, steal siderophores from other micro-organisms and make use of their degradation products, for example by scavenging the enterobactin linear dimer.

Structures of iron-binding siderophores

Research led by professors Keith S. Wilson and Anne-K, Duhme-Klair in the Department of Chemistry at York reveal that CeuE, the periplasmic siderophore-binding protein of C. jejuni, is adapted to bind the hydrolysis product of enterobactin via two key amino-acid side chains. This adaptation allows the pathogen to benefit from the enterobactin made by other bacteria and hence gain a competitive advantage by exploiting their resources.

This research was supported by the Engineering and Physical Sciences Research Council (EPSRC) and is published in Proceedings of the National Academy of Sciences of the United States of America (PNAS), DOI: 10.1073/PNAS.1520829113.  http://www.pnas.org/content/early/2016/05/05/1520829113