Friday, May 15, 2009

origin of life breakthrough

In the big jigsaw that is the origin of life, there are two well-researched areas, namely the prebiotic chemistry giving rise to simple molecules such as amino acids, and the RNA world scenario, which concludes from today's peculiarities of biomolecules that RNA carried both genetic information and catalytic function in life before the evolution of proteins and DNA.

So far, there has been a huge gap between these two areas, as nobody could explain how prebiotic chemistry may have led to RNA. Now John Sutherland's group at Manchester has found a highly original new chemical approach to the issue. Bypassing the fundamental problem that the building blocks ribose, phosphate and the four information carrying nitrogen bases will not hook up in the right way under prebiotic conditions, the group found a new intermediate, 2-aminooxazole, which can be plausibly produced in a prebiotic setting, and which in turn can react to form a nucleoside including both the ribose and the pyrimidine base directly, without the need for a step hitching the sugar to the base.

While a similar path to purine bases remains to be discovered, I would reckon that this may well be the the biggest breakthrough in the origin of life field since the Urey Miller experiment more than 50 years ago. Suddenly, a complete solution, from prebiotic reactions to replicating living systems appears to be possible.

Reference:

Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions p239
At some stage in the origin of life, an information-carrying polymer must have formed by purely chemical means. That polymer might have been RNA, but until now this theory has been hampered by a lack of evidence for a plausible route in which the ribonucleotides could have formed on prebiotic Earth. Here, just such a route is reported.
Matthew W. Powner, Béatrice Gerland & John D. Sutherland
doi:10.1038/nature08013


News and Views:

Origins of life: Systems chemistry on early Earth p171
Understanding how life emerged on Earth is one of the greatest challenges facing modern chemistry. A new way of looking at the synthesis of RNA sidesteps a thorny problem in the field.
Jack W. Szostak
doi:10.1038/459171a

No comments:

Related Posts with Thumbnails