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NewswireToday - /newswire/ -
Honolulu, HI, United States, 08/23/2006 - Some microbes are able to tolerate radioactivity and other toxic environments because they developed detoxification mechanisms that allow them to resist adverse environments without being damaged..
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These protective mechanisms increasingly are of great interest to scientists not only for developing innovative remediation strategies but also for creating novel biotechnological applications. As a recent example, researchers in Germany managed to produce highly stable and regular palladium (Pd) nanoparticles by harnessing the survival mechanism of bacteria found in uranium-polluted waste. These particles showed much improved catalytic activity and other new physical properties, which make them ideal for use as nanocatalysts or nanosensors.
Back in 1997, a team of biologists from the Institute of Radiochemistry at the Forschungszentrum Rossendorf (FZR) in Dresden, Germany, discovered a microbe called Bacillus sphaericus JG-A12 in the waste of an uranium mining site. JG-A12 exhibits a high metal-binding capacity, indicating that it might provide a protective function by preventing the cellular uptake of heavy metals and radionuclides.
The researchers working on interactions of actinides with biomolecular surfaces found that JG-A12 protects itself from the toxicity of uranium by selectively binding large amounts of the toxic metal on its protective protein surface layer (S-layer). The S-layers are surface structures of bacteria that form highly regular protein lattices, covering the whole cell. The lattice pores measure only a few nanometers.
Dr. Sonja Selenska-Pobell, the group leader Molecular Microbiology in the Institute of Radiochemistry at the FZR, explained the recent findings to Nanowerk: "Although JG-A12's properties allowed us to use S-layers as self-assembling organic templates for the synthesis of heavy metal nanocluster arrays, we knew little about the molecular basis of the metal-protein interactions and their impact on secondary structure."
In recent work ("Secondary Structure and Pd(II) Coordination in S-Layer Proteins from Bacillus sphaericus Studied by Infrared and X-Ray Absorption Spectroscopy"), Selenska-Pobell and her colleagues localized the sites on the S-layer protein of JG-A12 that are involved in the metal complexation.
Read the full article on the Nanowerk website.
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By Michael Berger, Copyright 2006 Nanowerk LLC
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editor[.]nanowerk.com 
