Trifecta Chemistry Fashions Prebiotic Purine Precursors

Last year, chemists at the University of Manchester, in England, made headlines in the origin-of-life field by developing a recipe for pyrimidine ribonucleotides, which are two of the four fundamental units of RNA, that works under conditions thought to be feasible during Earth’s earliest days (C&EN, Dec. 21, 2009, page 37). Part of that team—John D. Sutherland, now at the University of Cambridge, and Matthew W. Powner, now a postdoctoral fellow with Jack W. Szostak at Harvard University—has found a three-component reaction that makes precursors of the pyrimidines’ purine counterparts (J. Am. Chem. Soc., DOI: 10.1021/ja108197s). The reaction runs in water and combines a variety of aldehydes (blue) with a 5-aminoimidazole (red) and a 2-aminooxazole (green). The imidazole can arise from cyanide tetramers and has been studied as a purine precursor, and the oxazole is a building block the team relied on in the previous study. “What’s key about this work is that it plays off the same chemistry that so robustly takes you to the pyrimidines,” because in the origin-of-life field it’s important to find chemical pathways by which the four ribonucleotides may have come about, explains RNA researcher Gerald F. Joyce of Scripps Research Institute.