Finding life doing the oddest things

mono lake by KidsLoveAnimals
Subsisting on Arsenic, a Microbe May Redefine Life
[Via NYT > Science]

Researchers said that the bacterium was trained to grow without phosphorus, one of six elements considered essential for life.

[More]

Thirty years ago, a professor of mine described how a bottle of arsenic in his lab refrigerator was contaminated with something– something was growing in it. So he tossed it out. Only then did his forebrain hit him – what the heck grows in arsenic? I think we know.

This substantially alters what we can expect life to look like and what elements it decides to use. Arsenic is one row down from phosphorus, so it has some similar chemical properties.

But it is normally toxic to life. Here, scientists have found a bacteria that can replace its phosphorus atoms with arsenic. That means that the very structure of its DNA, which contains large amounts of phosphorus, now use arsenic. It also means that the major source of the energy needed for its metabolism, adenosine triphosphate (ATP), must also have been altered.

This suggest huge changes in the metabolism of the bacteria because I would expect something like adenosine triarsenate to have very different energy potentials than ATP. Current metabolic pathways are known the require the energy provided by the high energy binds of ATP. I would think that ATA would be very different possible causing substantial alteration of the metabolism.

As the researchers found, the bugs like phosphorus better – probably because of the more energy efficient ATP – and they have not yet shown that working DNA has no phosphorus. It may be that the bugs have recycled the phosphorus that they did have access to.

But there has to be some really interesting metabolism going on here. What sorts of proteins don’t get made because of the different energy carriers, ATP and ATA.

One thought on “Finding life doing the oddest things

  1. In centuries past, women would use an arsenic paste to make their complextion whiter. (Good Queen Bess did). In the 1800’s, there were arsenic eaters. They started with small amounts and worked their way up to some large amounts. I can’t remember the reason, but maybe it was a deficiency of some sort. Anyway, I wonder what arsenic did to their metabolism.

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