NASA Confirms Discovery of Organism With Phosphorus-Free DNA 380
GNUALMAFUERTE writes "As we mentioned before, NASA's Department of Astrobiology had an important announcement to make today. It looks like Gizmodo was right. You can watch the presentation online right now. It looks like the bacteria in question uses arsenic as a phosphorus replacement in its DNA."
Re:Not Phosphorus-Free (Score:5, Interesting)
Re:Not Phosphorus-Free (Score:4, Interesting)
In fact arsenic is toxic to you precisely because it takes the place of phosphorus so easily, without doing all of the jobs. Except for this little guy, who manages to work around the differences and survive nearly phosphorus-free.
Makes me wonder if this is an organism which has adapted to tolerate the damage from arsenic which would kill us.
Re:News flash: NASA discoveres there's life on ear (Score:4, Interesting)
This link [purdue.edu] may help. If not (it is, after all, a link to the chemistry department of a university), this [wikipedia.org], this [wikipedia.org], or this [wikipedia.org] may.
And yes, since it has to do with DNA it is indeed porn on acid. Or maybe acid on porn.
Re:News flash: NASA discoveres there's life on ear (Score:4, Interesting)
the cell has either found a way to strengthen the backbone or has developed an amazing repair mechanism which can deal with frequent DNA damage
Hmmm. Maybe it methylates the DNA more? Or the histones are different. I guess - as you say - more repair enzymes is quite likely, since that just requires some promoter mutations.
The interesting question for me is whether any of the mechanisms are different for this organisms enzymes. For the last few months I've been sitting on the next desk to the maintainer of a database of biochemical mechanisms (MACiE - hi gemma, assuming you read slashdot, and happy birthday...) so maybe that's why it occurs to me. Many enzymes use ATP/NAD/other phosphate cofactors to make stuff, so if AsO4 has a slightly different chemistry, I wonder if different sidechains are used. Or, as I say, some completely different mechanisms (or pathways?).
Re:Not Phosphorus-Free (Score:5, Interesting)
Re:News flash: NASA discoveres there's life on ear (Score:4, Interesting)
Re:News flash: NASA discoveres there's life on ear (Score:4, Interesting)
Thanks for filling in the blanks. There's some things that I deal with so often that I forget I can sound a little weird when I get excited about science and open my mouth - phosphate is one of them.
But yeah - the short story is that phosphate (and arsenate) have three spots to kick hydrogen on or off with - and the number of hydrogens that hang out on a phosphate ion is very much related to the pH.
The long story (for anyone who cares) is that each of those hydrogens has a different equilibrium constant (pKa) at which it will pop off. H3PO4 is phosphoric acid but if you increase the amount of OH- in solution (or reduce the amount of H+) the first of those hydrogens will hook up with the OH- to make water which leaves H2PO4-. So the next hydrogen to take a hike will leave the phosphate at HPO4- - which means it's harder to leave and has a different pH (which is a fancy way of talking about the levels of H+ and OH- in water) it will hit equilibrium with. So on and so forth for each of the four phosphate species (0, -1, -2, -3 charge).
The really long version throws out concentration of the different species of phosphate and talks about activities, taking into account that the activity coefficient is affected by the square of the ion's charge... [We interrupt this chemistry lesson for the sake of sanity]
Strange - I forgot what I was talking about - but back to your question: yeah - DNA is both sex and acid
Holy crap! (Score:4, Interesting)
What if this microbe isn't "new" - what if it is old?
As in - what if life on Terra initially evolved based around an arsenic atom, and then later evolved to use the much better and more stable phosphorus?
DG