Researchers from the University of Groningen have clarified the structure of an enzyme that disturbs the communication processes between bacteria. By doing so they have laid the foundations for a new method of tackling bacterial infections such as cystic fibrosis. An article on the structure and function of the so-called quorum-quenching acylase was published on 21 December 2009 in the online edition of the Proceedings of the National Academy of Sciences of the United States of America (PNAS).
Although bacteria are simple single-celled organisms, they are capable of communicating with each other. Bacteria talk to each other by exchanging tiny hormone-like signal molecules. By means of this process of 'quorum sensing', the activities of a large group of bacteria are synchronized. Thus bacteria can adapt quickly to changes in their environment such as the running out of nutrients or the arrival of rival microorganisms.
The production of factors that determine the virulence of a bacterium is also controlled by these signal molecules. This enables bacteria to remain invisible to the immune system in the early stages of infection. As soon as the group of informed bacteria -- the quorum -- is sufficiently large, the attack on the infected host is initiated by starting up the production of toxins and other virulence factors.
The quorum-quenching acylase of which the Groningen research team has determined the structure is capable of cutting off these signal molecules. As a result, the communication processes between pathogenic bacteria are disturbed. The enzyme turns out to suppress the virulence of the lung bacteria Pseudomonas aeruginosa, the most important pathogen for cystic fibrosis.
The clarified structure of the bacterial jammer provides insight into the precise functioning of the acylase and could be the first step in the development of a new antibacterial therapy.
- Bokhove, M., Nadal Jimenez, P., Quax, W.J. and B. W. Dijkstra. The quorum-quenching N-acyl homoserine lactone acylase PvdQ is an Ntn-hydrolase with an unusual substrate-binding pocket. Proceedings of the National Academy of Sciences of the United States of America, 2009-11839R Early Edition
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