Asian Scientist (Aug. 6, 2013) – New Zealand and Australian scientists have uncovered a new way in which bacteria store and release toxins. The discovery paves the way for bacterial toxins to be harnessed for developing bioinsecticides and even new medicines.
In their study, published in Nature, the researchers discovered that the bacterium Yersinia entomophaga packages its insect-killing toxin in a hollow protein shell. They made the discovery while examining how the bacterium kills crop pests such as grass grubs, diamondback moths and porina caterpillars.
The scientists used high-resolution x-ray crystallography and electron microscopy to determine the three-dimensional structure of proteins produced by the bacterium.
In the process, they found that the proteins form a hollow shell that releases the toxin only when it encounters specific environmental conditions, such as those found in the gut of crop pests. This explains how the bacterium can produce toxins without harming itself, and release them only when needed.
The genetic sequence that provides the blueprint for the shell is also found in many other species, including animals, and the researchers believe they have discovered a new biological mechanism by which toxins or other sensitive molecules may be stored and released.
According to the researchers, scientists may be able to generate new insecticides or even new medicines based on the discovery.
“This is a mechanism for delivery, and you could pack whatever you want into the shell. You could develop different toxins for use as bioinsecticides, or package therapeutic molecules that you want to deliver only in specific conditions,” said Dr Shaun Lott, a senior author of the study.
The article can be found at: Busby et al. (2013) The BC Component Of ABC Toxins Is An RHS-Repeat-Containing Protein Encapsulation Device.
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Source: University of Auckland; Photo: kaibara87/Flikcr/CC.
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