Purple extremist thrives under inhospitable ...( This release is available in A HREF h...)

Mild environmental conditions are a prerequisite for life. Strong acids or dissolved metallic salts in high concentrations are detrimental to both humans and to simpler life forms, such as bacteria. Such conditions destroy proteins, ensuring that all biological functions in the cells come to a standstill. So what do we find at the limits of hostile conditions where we still find life? Scientists at the Helmholtz Centre for Infection Research (HZI) in Braunschweig (Germany) have joined up with colleagues from Spain and Great Britain to identify an enzyme that requires acids and dissolved metals in order to function. The team describes its findings regarding the extreme protein of the archaebacterium Ferroplasma acidiphilum in the latest online edition of the renowned US research journal PNAS.

HZI scientist Dr. Olga Golyshina discovered Ferroplasma ten years ago and has been endeavouring to unlock its secrets ever since. "This organism is ideally adapted to extremely hostile environments. It likes to live in highly acidic solutions containing toxic heavy metals. It is unable to exist at all under normal conditions," she says, describing her research object. "We recently noted that Ferroplasma is unique in the world of living organisms, as it contains iron in high concentrations. Now we aim to discover how its proteins function under such extreme conditions."

For this purpose the team has selected a so-called DNA ligase. Enzymes of this type play a central role in important metabolic processes such as the duplication of genetic material in dividing cells and the repair of genetic damage. All DNA ligases investigated so far, including the DNA ligases of the so-called extremophile microorganisms that live in particularly inhospitable habitats which are either acidic, alkaline, hot or cold, , re
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