The Origin and Evolution of Ribonucleotide Reduction

Life

Daniel Lundin¹  Gustav Berggren¹  Derek T. Logan²  Britt-Marie Sjrg¹ 

[1] Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, SE-106 91 Stockholm, Sweden; E-Mails:;Department of Biochemistry and Structural Biology, Lund University, Box 124, SE-221 00 Lund, Sweden; E-Mail:

关键词: ribonucleotide reductase (RNR);    RNA/RNP world;    DNA building blocks;    protein evolution;    redox chemistry;    radical chemistry;    deoxyribonucleotides;    primordial hydrogen atom abstraction;    structural phylogenetics;    allosteric regulation;   

DOI  :  10.3390/life5010604

来源: mdpi

【 摘 要 】

Ribonucleotide reduction is the only pathway for de novo synthesis of deoxyribonucleotides in extant organisms. This chemically demanding reaction, which proceeds via a carbon-centered free radical, is catalyzed by ribonucleotide reductase (RNR). The mechanism has been deemed unlikely to be catalyzed by a ribozyme, creating an enigma regarding how the building blocks for DNA were synthesized at the transition from RNA- to DNA-encoded genomes. While it is entirely possible that a different pathway was later replaced with the modern mechanism, here we explore the evolutionary and biochemical limits for an origin of the mechanism in the RNA + protein world and suggest a model for a prototypical ribonucleotide reductase (protoRNR). From the protoRNR evolved the ancestor to modern RNRs, the urRNR, which diversified into the modern three classes. Since the initial radical generation differs between the three modern classes, it is difficult to establish how it was generated in the urRNR. Here we suggest a model that is similar to the B₁₂-dependent mechanism in modern class II RNRs.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.