Autocatalytic replication and homochirality in biopolymers: Is homochirality a requirement of life or a result of it?

Meng Wu, Sara Walker, Paul G. Higgs

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

A key step in the origin of life is the establishment of autocatalytic cycles controlled by biopolymer catalysts. These catalysts (either ribozymes or proteins) are composed of homochiral monomers. Homochirality in living systems is maintained because biopolymers are asymmetric in their catalysis and synthesize molecules of their own handedness. Asymmetric autocatalysis is also possible with small molecules, as demonstrated by the Soai reaction, but it is rare. As far as we know, single nucleotides and amino acids are not autocatalytic. The observation that organic molecules in meteorites can have an enantiomeric excess of a few percent suggests that the prebiotic mixture may have had a partial chiral bias that was caused by external physical influences. Here, we consider the way that such a partial prebiotic bias would influence the origin of ribozymes in an RNA world scenario. We have previously shown how a transition to a living state can occur in a model for RNA polymerization. Here, we add chirality to the problem by considering simultaneous synthesis and polymerization of left- and right-handed monomers. The two chemical synthesis rates may be equal or unequal, due to physical or chemical effects prior to the origin of life. We determine the stationary states of this reaction system. The nonliving state is racemic, or slightly biased. There are two living states that are almost completely homochiral, whether or not the nonliving state is biased. It is a feature of our model that, for some regions of parameter space, living and nonliving states are both found to be stable under the same conditions. The origin of life therefore involves a stochastic transition between the nonliving and living states. Our model extends previous theories by treating the origin of life and the origin of chirality as aspects of the same model.

Original languageEnglish (US)
Pages (from-to)818-829
Number of pages12
JournalAstrobiology
Volume12
Issue number9
DOIs
StatePublished - Sep 1 2012

Fingerprint

origin of life
Biopolymers
biopolymers
Prebiotics
Catalytic RNA
requirements
prebiotics
catalysts
polymerization
Polymerization
RNA
Meteoroids
catalyst
handedness
chirality
Functional Laterality
synthesis
catalysis
monomers
Catalysis

Keywords

  • Chirality
  • Origin of life
  • Prebiotic chemistry
  • RNA world

ASJC Scopus subject areas

  • Space and Planetary Science
  • Agricultural and Biological Sciences (miscellaneous)

Cite this

Autocatalytic replication and homochirality in biopolymers : Is homochirality a requirement of life or a result of it? / Wu, Meng; Walker, Sara; Higgs, Paul G.

In: Astrobiology, Vol. 12, No. 9, 01.09.2012, p. 818-829.

Research output: Contribution to journalArticle

@article{b383cea77d2a4f7098ad5b2256de3ace,
title = "Autocatalytic replication and homochirality in biopolymers: Is homochirality a requirement of life or a result of it?",
abstract = "A key step in the origin of life is the establishment of autocatalytic cycles controlled by biopolymer catalysts. These catalysts (either ribozymes or proteins) are composed of homochiral monomers. Homochirality in living systems is maintained because biopolymers are asymmetric in their catalysis and synthesize molecules of their own handedness. Asymmetric autocatalysis is also possible with small molecules, as demonstrated by the Soai reaction, but it is rare. As far as we know, single nucleotides and amino acids are not autocatalytic. The observation that organic molecules in meteorites can have an enantiomeric excess of a few percent suggests that the prebiotic mixture may have had a partial chiral bias that was caused by external physical influences. Here, we consider the way that such a partial prebiotic bias would influence the origin of ribozymes in an RNA world scenario. We have previously shown how a transition to a living state can occur in a model for RNA polymerization. Here, we add chirality to the problem by considering simultaneous synthesis and polymerization of left- and right-handed monomers. The two chemical synthesis rates may be equal or unequal, due to physical or chemical effects prior to the origin of life. We determine the stationary states of this reaction system. The nonliving state is racemic, or slightly biased. There are two living states that are almost completely homochiral, whether or not the nonliving state is biased. It is a feature of our model that, for some regions of parameter space, living and nonliving states are both found to be stable under the same conditions. The origin of life therefore involves a stochastic transition between the nonliving and living states. Our model extends previous theories by treating the origin of life and the origin of chirality as aspects of the same model.",
keywords = "Chirality, Origin of life, Prebiotic chemistry, RNA world",
author = "Meng Wu and Sara Walker and Higgs, {Paul G.}",
year = "2012",
month = "9",
day = "1",
doi = "10.1089/ast.2012.0819",
language = "English (US)",
volume = "12",
pages = "818--829",
journal = "Astrobiology",
issn = "1531-1074",
publisher = "Mary Ann Liebert Inc.",
number = "9",

}

TY - JOUR

T1 - Autocatalytic replication and homochirality in biopolymers

T2 - Is homochirality a requirement of life or a result of it?

AU - Wu, Meng

AU - Walker, Sara

AU - Higgs, Paul G.

PY - 2012/9/1

Y1 - 2012/9/1

N2 - A key step in the origin of life is the establishment of autocatalytic cycles controlled by biopolymer catalysts. These catalysts (either ribozymes or proteins) are composed of homochiral monomers. Homochirality in living systems is maintained because biopolymers are asymmetric in their catalysis and synthesize molecules of their own handedness. Asymmetric autocatalysis is also possible with small molecules, as demonstrated by the Soai reaction, but it is rare. As far as we know, single nucleotides and amino acids are not autocatalytic. The observation that organic molecules in meteorites can have an enantiomeric excess of a few percent suggests that the prebiotic mixture may have had a partial chiral bias that was caused by external physical influences. Here, we consider the way that such a partial prebiotic bias would influence the origin of ribozymes in an RNA world scenario. We have previously shown how a transition to a living state can occur in a model for RNA polymerization. Here, we add chirality to the problem by considering simultaneous synthesis and polymerization of left- and right-handed monomers. The two chemical synthesis rates may be equal or unequal, due to physical or chemical effects prior to the origin of life. We determine the stationary states of this reaction system. The nonliving state is racemic, or slightly biased. There are two living states that are almost completely homochiral, whether or not the nonliving state is biased. It is a feature of our model that, for some regions of parameter space, living and nonliving states are both found to be stable under the same conditions. The origin of life therefore involves a stochastic transition between the nonliving and living states. Our model extends previous theories by treating the origin of life and the origin of chirality as aspects of the same model.

AB - A key step in the origin of life is the establishment of autocatalytic cycles controlled by biopolymer catalysts. These catalysts (either ribozymes or proteins) are composed of homochiral monomers. Homochirality in living systems is maintained because biopolymers are asymmetric in their catalysis and synthesize molecules of their own handedness. Asymmetric autocatalysis is also possible with small molecules, as demonstrated by the Soai reaction, but it is rare. As far as we know, single nucleotides and amino acids are not autocatalytic. The observation that organic molecules in meteorites can have an enantiomeric excess of a few percent suggests that the prebiotic mixture may have had a partial chiral bias that was caused by external physical influences. Here, we consider the way that such a partial prebiotic bias would influence the origin of ribozymes in an RNA world scenario. We have previously shown how a transition to a living state can occur in a model for RNA polymerization. Here, we add chirality to the problem by considering simultaneous synthesis and polymerization of left- and right-handed monomers. The two chemical synthesis rates may be equal or unequal, due to physical or chemical effects prior to the origin of life. We determine the stationary states of this reaction system. The nonliving state is racemic, or slightly biased. There are two living states that are almost completely homochiral, whether or not the nonliving state is biased. It is a feature of our model that, for some regions of parameter space, living and nonliving states are both found to be stable under the same conditions. The origin of life therefore involves a stochastic transition between the nonliving and living states. Our model extends previous theories by treating the origin of life and the origin of chirality as aspects of the same model.

KW - Chirality

KW - Origin of life

KW - Prebiotic chemistry

KW - RNA world

UR - http://www.scopus.com/inward/record.url?scp=84866509362&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84866509362&partnerID=8YFLogxK

U2 - 10.1089/ast.2012.0819

DO - 10.1089/ast.2012.0819

M3 - Article

C2 - 22931294

AN - SCOPUS:84866509362

VL - 12

SP - 818

EP - 829

JO - Astrobiology

JF - Astrobiology

SN - 1531-1074

IS - 9

ER -