title: Deoxyribonucleotide synthesis and the emergence of DNA in molecular evolution.
abstract: DNA replication requires monomeric deoxyribonucleotides, which cannot be regarded as primary products of organic syntheses on a primitive earth. However, the present biosynthetic pathway--reductive elimination of the 2'-OH group from ribonucleotides, catalyzed by ribonucleotide reductases and thioredoxins--suggests an early, polyphyletic combination of protein-nucleotide interactions and metal catalysis. That key process had to precede the upcome of RNA-DNA dualism on the way from RNA-protein protocells to true organisms.
mesh_terms: D001419:Bacteria / Q000378:metabolism; D005075:Biological Evolution; D004247:DNA / Q000235:genetics*; D004261:DNA Replication; D003854:Deoxyribonucleotides / Q000096:biosynthesis*; D005658:Fungi / Q000378:metabolism; D010084:Oxidation-Reduction; D012264:Ribonucleotide Reductases / Q000378:metabolism; D012265:Ribonucleotides / Q000378:metabolism; D013045:Species Specificity; D013879:Thioredoxins / Q000378:metabolism
chemical_list: D003854:Deoxyribonucleotides; D012265:Ribonucleotides; D013879:Thioredoxins; D004247:DNA; D012264:Ribonucleotide Reductases