rna901

http://www.nature.com/nature/journal/v459/n7244/abs/nature08013.html

Letter

Nature 459, 239-242 (14 May 2009) | doi:10.1038/nature08013; Received 11 December 2008; Accepted 24 March 2009

Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions

Matthew W. Powner¹, Béatrice Gerland¹ & John D. Sutherland¹

School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK

Correspondence to: John D. Sutherland¹ Correspondence and requests for materials should be addressed to J.D.S. (Email: john.sutherland@manchester.ac.uk).

At some stage in the origin of life, an informational polymer must have arisen by purely chemical means. According to one version of the 'RNA world' hypothesis^{1, 2, 3} this polymer was RNA, but attempts to provide experimental support for this have failed^{4, 5}. In particular, although there has been some success demonstrating that 'activated' ribonucleotides can polymerize to form RNA^{6, 7}, it is far from obvious how such ribonucleotides could have formed from their constituent parts (ribose and nucleobases). Ribose is difficult to form selectively^8,9, and the addition of nucleobases to ribose is inefficient in the case of purines¹⁰ and does not occur at all in the case of the canonical pyrimidines¹¹. Here we show that activated pyrimidine ribonucleotides can be formed in a short sequence that bypasses free ribose and the nucleobases, and instead proceeds through arabinose amino-oxazoline and anhydronucleoside intermediates. The starting materials for the synthesis—cyanamide, cyanoacetylene, glycolaldehyde, glyceraldehyde and inorganic phosphate—are plausible prebiotic feedstock molecules^{12, 13, 14, 15}, and the conditions of the synthesis are consistent with potential early-Earth geochemical models. Although inorganic phosphate is only incorporated into the nucleotides at a late stage of the sequence, its presence from the start is essential as it controls three reactions in the earlier stages by acting as a general acid/base catalyst, a nucleophilic catalyst, a pH buffer and a chemical buffer. For prebiotic reaction sequences, our results highlight the importance of working with mixed chemical systems in which reactants for a particular reaction step can also control other steps.

rna901

Letter

Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions

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