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The origin of biological homochirality along with the origin of life

Fig 4

The emergence of ribozymes in the chirality-deviation background and subsequent enhancement of the chirality-deviation.

(a) The spontaneous appearance of NSR (with a uniform-handedness catalytic domain) in a chirality-deviation background established by the surface-mediated synthesis and the template-directed synthesis, and its effect of augmenting the enantiomeric excess. REP is not considered (i.e., PTLR = 0). About the primer effect in surface-mediated synthesis: Rn-mer = R3-mer = 2×R2-mer = 20×R1-mer (PRL is multiplied by one of such rates in corresponding situation; the scale of these rates are generally in accordance with experiments [29,30]; about the primer effect in template-directed synthesis: Rn-mer = R3-mer = 2×R2-mer = 10×R1-mer (PTL is multiplied by one of such rates in corresponding situation; the scale of these rates are generally in accordance with experiments [27,28]). See Fig 5 and S1 Movie for the evolutionary scenario of this case. (b) The spontaneous appearance of REP (with a uniform-handedness catalytic domain) in a chirality-deviation background established by the surface-mediated synthesis and the template-directed synthesis, and its effect of augmenting the enantiomeric excess. NSR is not considered (i.e., PNFR = 0). The situation about the primer effects are the same as that assumed in (a). For the panels of chain-length distribution, the chains longer than 20 nt are not displayed. Note that the prevailing of D-RNA and corresponding ribozymes shown in these two cases is merely by chance (i.e., in other cases L-type ones might show up).

Fig 4

doi: https://doi.org/10.1371/journal.pcbi.1007592.g004