Nucleotide synthetase ribozymes may have emerged first in the RNA world |
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Authors: | Ma Wentao Yu Chunwu Zhang Wentao Hu Jiming |
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Institution: | College of Life Sciences, Wuhan University, Wuhan, PR China. mwt@whu.edu.cn |
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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. |
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Keywords: | nucleotide pool self-replication RNA catalysis Darwinian evolution Monte Carlo method |
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