Have deoxyribonucleotides and DNA been among the earliest biomolecules?
Unlike ribose chemistry, the chemistry of 2-deoxyribose precludes its formation or at least its incorporation into nucleotides under accepted "primordial soup" conditions; therefore RNA and DNA could not develop in parallel during the evolution of protocells. However, deoxyribonucleotides might have been formed abiotically by direct reduction of ribonucleotides in a primitive version of the biochemical pathway. This sequence of events, in which DNA lagged behind RNA in the assembly of genetic information for an unknown--probably short--period of time is suggested by the primitive traits (i.e., nucleotide binding, thiol redox chemistry, and metal ion catalysis) of present-day enzyme systems of deoxyribonucleotide biosynthesis. The reaction should be amenable to experimental study.
Follmann
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Fachbereich Chemie (Biochemie) der Philipps-Universitat, Marburg, FRG.
D002241:Carbohydrates / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D003854:Deoxyribonucleotides / Q000737:chemistry*; D003855:Deoxyribose / Q000737:chemistry; D019143:Evolution, Molecular; D017665:Hydroxyl Radical; D000069497:Origin of Life; D012264:Ribonucleotide Reductases / Q000737:chemistry*
D002241:Carbohydrates; D003854:Deoxyribonucleotides; D017665:Hydroxyl Radical; D003855:Deoxyribose; D004247:DNA; D012264:Ribonucleotide Reductases