Tack för länken, ErikS. Om det stämmer så verkar det vara sant att arseniken faktiskt kan ersätta fosfor i DNA:t.
"You may have seen Internet speculation December 1, 2010 about a NASA announcement related to the search for extra-terrestrial life. The online rumors weren't quite right. But from a science perspective, a paper being published 2 December by the journal Science does describe a pretty amazing microbe. Scientists have discovered bacteria that can live and grow entirely off poison, arsenic (rather than the usual phosphate). Found in California's Mono Lake, the salt-loving bacteria, a member of the Halomonadaceae family of proteobacteria, may support NASA's astrobiology program because it suggests that the requirements for life's basic building blocks may be more flexible than we thought. In the lab, the researchers grew the bacteria in Petri dishes in which phosphate salt was gradually replaced by arsenic, until the bacteria could grow without needing phosphate, an essential building block for various macromolecules present in all cells, including nucleic acids, lipids and proteins. Using radio-tracers, the team closely followed the path of arsenic in the bacteria; from the chemical's uptake to its incorporation into various cellular components. Arsenic had completely replaced phosphate in the molecules of the bacteria, right down its DNA. The work by Felisa Wolfe-Simon and colleagues can be found online at
http://www.sciencemag.org. For public information on this research, please see
http://www.eurekalert.org and look for "Breaking News.""
På ett sätt låter det lite märkligt. Om arsenik då ersätter fosfat i DNA:t så måste väl strukturen påverkas? Och i och med det så borde enzymerna som avläser DNA:t får svårare att jobba?
Verkat också ha ersatt fosfor i proteiner och vissa lipider då, vilket också verkar mycket märkligt. Helt identiska är de ju inte direkt...