‘Arsenic-life’ bacterium prefers phosphorus after all

NATURE NEWS ^ | 03 October 2012 | Daniel Cressey

[neverdem]

Transport proteins show 4,000-fold preference for phosphate over arsenate.

A bacterium that some scientists thought could use arsenic in place of phosphorus in its DNA actually goes to extreme lengths to grab any traces of phosphorus it can find.

The finding clears up a lingering question sparked by a controversial study¹, published in Science in 2010, which claimed that the GFAJ-1 microbe could thrive in the high-arsenic conditions of Mono Lake in California without metabolizing phosphorus — an element that is essential for all forms of life.

Although this and other key claims of the paper were later undermined (see 'Study challenges existence of arsenic-based life'), it was not clear how bacteria discriminate between nearly identical molecules of phosphate (PO₄^3-) and arsenate (AsO₄^3-).

Dan Tawfik, who studies protein function at the Weizmann Institute of Science in Rehovot, Israel, and his colleagues have now teased out the mechanism by which some of the bacterial proteins bind to phosphate and not arsenate. The study, published today in Nature², suggests that just one chemical bond holds the key, and shows that the ‘arsenic-life’ bacteria have a strong preference for phosphorus over arsenic...

[Inyo-Mono]

I live just a few miles from Mono Lake. Oldest lake in North America.

[mtg]

The only reason the bacteria incorporated arsenic at all was because there was nothing else around; as soon as it found phosphorous, it readily replaced the arsenic.

[neverdem]

So what does Inyo stand for?

[CottShop]

just fro m the brief description, it doesn’t make clear whether the bacteria can live off just arsenic, or whether ‘if given a choice’ it prefers phosphorus? It seems from the short exerpt that it’s just a case of ‘if it’s around (the phosphorus), we’ll take it, if not, oh well- we’ll survive’?

[flaglady47]

I went to Mono Lake when in my early 20’s, and have never forgotten it. It looked like a lake on a moonscape. The whole scene was a bit creepy as nature looked like an alien place hear on earth. Fascinating though. A beautiful lake in such a strange way. I just haven’t ever forgotten seeing it. Such a strong impression it made on me. Loved looking at it.

[fella]

I've heard that human cells that can't get enough magnesium will substitute aluminum which causes all sorts of problems.

[Inyo-Mono]

“Indian Land.”

[neverdem]

Thank you.

[SunkenCiv]

Thanks neverdem.

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