title: Nucleotide synthetase ribozymes may have emerged first in the RNA world.
abstract: Though the "RNA world" hypothesis has gained a central role in ideas concerning the origin of life, the scenario concerning its emergence remains uncertain. It has been speculated that the first scene may have been the emergence of a template-dependent RNA synthetase ribozyme, which catalyzed its own replication: thus, "RNA replicase." However, the speculation remains uncertain, primarily because of the large sequence length requirement of such a replicase and the lack of a convincing mechanism to ensure its self-favoring features. Instead, we propose a nucleotide synthetase ribozyme as an alternative candidate, especially considering recent experimental evidence suggesting the possibility of effective nonenzymatic template-directed synthesis of RNA. A computer simulation was conducted to support our proposal. The conditions for the emergence of the nucleotide synthetase ribozyme are discussed, based on dynamic analysis on a computer. We suggest the template-dependent RNA synthetase ribozyme emerged later, perhaps after the emergence of protocells.
authors: College of Life Sciences, Wuhan University, Wuhan, PR China. mwt@whu.edu.cn
authors: Wentao
authors: W
authors: Ma
authors: Chunwu
authors: C
authors: Yu
authors: Wentao
authors: W
authors: Zhang
authors: Jiming
authors: J
authors: Hu
mesh_terms: D000818:Animals; D003198:Computer Simulation; D019143:Evolution, Molecular; D006801:Humans; D009010:Monte Carlo Method; D009711:Nucleotides / Q000096:biosynthesis; D012313:RNA / Q000378:metabolism*; D012316:RNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism*; D016337:RNA, Catalytic / Q000235:genetics* / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism
chemical_list: D009711:Nucleotides; D016337:RNA, Catalytic; D012313:RNA; D012316:RNA Nucleotidyltransferases; D012324:RNA-Dependent RNA Polymerase