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An Extended Model for the Evolution of Prebiotic Homochirality: A Bottom-Up Approach to the Origin of Life

  • Marcelo Gleiser
  • Sara Imari Walker
Chirality

Abstract

A generalized autocatalytic model for chiral polymerization is investigated in detail. Apart from enantiomeric cross-inhibition, the model allows for the autogenic (non-catalytic) formation of left and right-handed monomers from a substrate with reaction rates ε L and ε R , respectively. The spatiotemporal evolution of the net chiral asymmetry is studied for models with several values of the maximum polymer length, N. For N = 2, we study the validity of the adiabatic approximation often cited in the literature. We show that the approximation obtains the correct equilibrium values of the net chirality, but fails to reproduce the short time behavior. We show also that the autogenic term in the full N = 2 model behaves as a control parameter in a chiral symmetry-breaking phase transition leading to full homochirality from racemic initial conditions. We study the dynamics of the N→ ∞ model with symmetric (ε L  = ε R ) autogenic formation, showing that it only achieves homochirality for ε > ε c , where ε c is an N-dependent critical value. For ε ≤ ε c we investigate the behavior of models with several values of N, showing that the net chiral asymmetry grows as tanh(N). We show that for a given symmetric autogenic reaction rate, the net chirality and the concentrations of chirally pure polymers increase with the maximum polymer length in the model. We briefly discuss the consequences of our results for the development of homochirality in prebiotic Earth and possible experimental verification of our findings.

Keywords

Homochirality Prebiotic chemistry Origin of life Early planetary environments 

References

  1. Blackmond DG (2004) Asymmetric autocatalysis and its implications for the origin of homochirality. Proc Natl Acad Sci U S A 101:5732–5736PubMedCrossRefGoogle Scholar
  2. Bonner WA (1996) The quest for chirality. In: Cline DD (ed) Physical origin of homochirality in life. Santa Monica, California, February 1995. AIP Conference Proceedings 379. AIP, New YorkGoogle Scholar
  3. Brandenburg A, Multamäki T (2004) How long can left and right handed life forms coexist? Int J Astrobiol 3:209–219CrossRefGoogle Scholar
  4. Brandenburg A, Andersen A, Nilsson M, Höfner ST (2005) Homochiral growth through enantiometric cross-inhibition. Orig Life Evol Biosph 35:225–241PubMedCrossRefGoogle Scholar
  5. Dunitz JD (1996) Symmetry arguments in chemistry. Proc Natl Acad Sci U S A 93:14260–14266PubMedCrossRefGoogle Scholar
  6. Engel MH, Macko SA (1997) Isotopic evidence for extraterrestrial non-racemic amino acids in the Murchison meteorite. Nature 389:265–268PubMedCrossRefGoogle Scholar
  7. Fitz D, Reiner H, Plankensteiner K, Rode BM (2007) Possible origins of biohomochirality. Curr Chem Biol 1:41–52CrossRefGoogle Scholar
  8. Frank FC (1953) On spontaneous asymmetric catalysis. Biochim Biophys Acta 11:459–463PubMedCrossRefGoogle Scholar
  9. Gleiser M (2007) Asymmetric spatiotemporal evolution of prebiotic homochirality. Orig Life Evol Biosph 37:235–251PubMedCrossRefGoogle Scholar
  10. Gleiser M, Thorarinson J (2006) Prebiotic homochiralirty as a critical phenomenon. Orig Life Evol Biosph 36:501–505PubMedCrossRefGoogle Scholar
  11. Gleiser M, Thorarinson J, Walker SI (2008) Punctuated chirality. arXiv:astro-ph/0802.1446 (in press)Google Scholar
  12. Goldenfeld N (1992) Lectures on phase transitions and the renormalization group. Addison Wesley, New YorkGoogle Scholar
  13. Gunton JD, San Miguel M, Sahni PS (1983) In: Domb C, Lebowitz JL (eds) Phase transitions and critical phenomena, vol 8. Academic, LondonGoogle Scholar
  14. Haken H (1983) Synergetics: an introduction. Springer, Berlin Heidelberg New YorkGoogle Scholar
  15. Joyce GF et al (1984) Chiral selection in poly(C)-directed synthesis of oligo(G). Nature 310:602PubMedCrossRefGoogle Scholar
  16. Kondepudi DK, Nelson GW (1985) Weak neutral currents and the origin of biomolecular chirality. Nature 314:438–441CrossRefGoogle Scholar
  17. Langer JS (1992) An introduction to the kinetics of first-order phase transitions. In: Godrèche C (ed) Solids far from equilibrium. Cambridge University Press, CambridgeGoogle Scholar
  18. Nilsson M, Brandenburg A, Anderson A, Höfner S (2005) Uni-directional polymerization leading to homochirality in the RNA world. Int J Astrobiol 4:233–239CrossRefGoogle Scholar
  19. Pizzarello S, Cronin JR (1998) Alanine enantiomers in the Murchison meteorite. Nature 394:236PubMedCrossRefGoogle Scholar
  20. Saito Y, Hyuga H (2004) Chirality selection models in a closed system. arXiv.org:physics/0408105Google Scholar
  21. Sandars PGH (2003) A toy model for the generation of homochirality during polymerization. Orig Life Evol Biosph 33:575–587PubMedCrossRefGoogle Scholar
  22. Sandars PGH (2005) Chirality in the RNA world and beyond. Int J Astrobiology 4:49–61CrossRefGoogle Scholar
  23. Soai K, Shibata T, Morioka H, Choji K (1995) Asymmetric autocatalysis and amplification of enantiometric excess of a chiral molecule. Nature 378:767–768CrossRefGoogle Scholar
  24. Wattis JA, Coveney PV (2005) Symmetry-breaking in chiral polymerization. Orig Life Evol Biosph 35:243–273PubMedCrossRefGoogle Scholar
  25. Yamagata Y (1966) A hypothesis for the asymmetric appearance of biomolecules on earth. J Theor Biol 11:495–498PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Department of Physics and AstronomyDartmouth College HanoverHanoverUSA

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