Nasa news conference (re: Arsenic-based life form?)

My first gut reaction was that the Kepler satellite had scanned the first exoplanet atmosphere. However, the inclusion of a molecular biologist on the panel tips it towards the bacteria or possibly new findings by one of the Mars probes.

Agreed. This goes beyond mutations which confer protein stability in high salt or temperature. This is NEW biochemistry at a very fundamental level. Something as conserved and basic as ATP was replaced by new chemistry. It is a big find that tells us that even the foundations of long standing evolved pathways can still be changed to fit new conditions.Edited by Taq, : No reason given.

"New" as in all other life we know of uses phosphate attached to an adenosine as a fundamental storehouse of energy while these bacteria use arsenate instead (and by extension the arsenate backbone of their DNA). If it so easy to switch between the two then why isn't it more common? It's not as if these bacteria have produced a protein that breaks down arsenic to reduce it's toxicity (which is what bacteria do for many antibiotics). Instead, this bacteria has turned a toxin into an integral part of it's metabolism.I guess that the coolness of this is quite subjective, but from my own view as someone who has worked in the lab with metabolism and protein chemistry this is pretty cool stuff.

I guess I view it through a different lens. Biologists have many speculations about many things. It is going from speculation to verification that is the exciting part. Speculating that bacteria could replace phosphate with arsenate in something as fundamental as ATP is one thing. Showing it is another. To use an analogy, people had long speculated that humans could build a self powered flying machine. This didn't take away from the achievements of the Wright Bros.As for the astrobiology aspect of the study, it is one thing to say that life could replace phosphates with arsenates, and it is an entirely different thing to show that it can indeed do it.