NASA announcement coming December 2nd.


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hmm, a direct replacement of arsenic in phosphorus ... group 5 element chemistry

i wonder what advances will this bring, not in the search for life, but in biochemistry?

isnt it ironic that the very same reason that arsenic is so poisonous to us, which is the similarity between arsenic and phosphorus, is also how this bacteria can exist at all?

thinking about it, i think that what is more curious is how the arsenic percentage seems to be variable in the DNA, as if some of the phosphorus could be substituted with arsenic... because of the non-regular nature of having some of the phosphorus get replaced by arsenic, wouldnt crystal data be quite unreliable?

like maybe if they knew the exact ratio of arsenic to phosphorus in the DNA, their x-ray diffraction might show a certain generalized shape, and the more arsenic there is, the more different it would be from a purely phosphorus-based DNA shape...

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hmm, a direct replacement of arsenic in phosphorus ... group 5 element chemistry

i wonder what advances will this bring, not in the search for life, but in biochemistry?

isnt it ironic that the very same reason that arsenic is so poisonous to us, which is the similarity between arsenic and phosphorus, is also how this bacteria can exist at all?

thinking about it, i think that what is more curious is how the arsenic percentage seems to be variable in the DNA, as if some of the phosphorus could be substituted with arsenic... because of the non-regular nature of having some of the phosphorus get replaced by arsenic, wouldnt crystal data be quite unreliable?

like maybe if they knew the exact ratio of arsenic to phosphorus in the DNA, their x-ray diffraction might show a certain generalized shape, and the more arsenic there is, the more different it would be from a purely phosphorus-based DNA shape...

DNA conformation plays a role in gene expression. Direct incorporation of arsenic to change the structure of specific regions of the chromosome may be an alternative means to regulate gene expression and the organism's phenotype, and we have no idea whether replacement of phosphorous with arsenic is a regulated process or not. Also keep in mind that DNA is chemically modified all the time; recall the purpose of DNA methylation.

Anyway, the biggest discovery here for me is that this organism might have some control over how much of its genome contains arsenic, and that it seems to be able to switch between the two.

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DNA conformation plays a role in gene expression. Direct incorporation of arsenic to change the structure of specific regions of the chromosome may be an alternative means to regulate gene expression and the organism's phenotype, and we have no idea whether replacement of phosphorous with arsenic is a regulated process or not. Also keep in mind that DNA is chemically modified all the time; recall the purpose of DNA methylation.

Anyway, the biggest discovery here for me is that this organism might have some control over how much of its genome contains arsenic, and that it seems to be able to switch between the two.

i've just had a thought, maybe the arsenic-containing DNA is actually a temporary and inactive form of DNA in the bacteria, and to perform its normal functions the arsenic needs to be swapped out with phosphorus... but then again im not a biologist so i dunno

yeah, the most interesting thing in this isnt arsenic alone, but how the bacteria can seamlessly use arsenic and phosphorus chemistry , and have phenotypical effects like having the cells get bigger when there is more arsenic in them and all that....

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i've just had a thought, maybe the arsenic-containing DNA is actually a temporary and inactive form of DNA in the bacteria, and to perform its normal functions the arsenic needs to be swapped out with phosphorus... but then again im not a biologist so i dunno

I think that it is unlikely that arsenated DNA isn't functional, since the organisms replicate in the absence of phosphates, provided that they can have arsenic instead.

Man, it would be cool to isolate the polymerase(s) of this organism and see whether you can do PCR using dNTAs'.

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I think that it is unlikely that arsenated DNA isn't functional, since the organisms replicate in the absence of phosphates, provided that they can have arsenic instead.

its not in the 'absence' of phosphates, its in trace quantities... i still think that the bacteria has evolved an enzyme or something which can safely swap phosphorus and arsenic in and out of the DNA and other cellular molecules

who is to say that the uptake of arsenic is actually spontaneous, while it is the cellular systems which is tolerant of the arsenic 'poisoning' ?like the cellular systems might have their own ways of replacing the arsenic with phosphorus just in time for 'traditional' cellular processes to happen, in effect establishing a sort of equilibrium between the original phosphorus molecules and the arsenic-substituted molecules

but then again, im no biologist, so i dunno....

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