Journal of Molecular Evolution

, Volume 39, Issue 6, pp 555–559 | Cite as

Production of RNA by a polymerase protein encapsulated within phospholipid vesicles

  • Ajoy C. Chakrabarti
  • Ronald R. Breaker
  • Gerald F. Joyce
  • David W. Deamer


Catalyzed polymerization reactions represent a primary anabolic activity of all cells. It can be assumed that early cells carried out such reactions, in which macromolecular catalysts were encapsulated within some type of boundary membrane. In the experiments described here, we show that a template-independent RNA polymerase (polynucleotide phosphorylase) can be encapsulated in dimyristoyl phosphatidylcholine vesicles without substrate. When the substrate adenosine diphosphate (ADP) was provided externally, long-chain RNA polymers were synthesized within the vesicles. Substrate flux was maximized by maintaining the vesicles at the phase transition temperature of the component lipid. A protease was introduced externally as an additional control. Free enzyme was inactivated under identical conditions. RNA products were visualized in situ by ethidium bromide fluorescence. The products were harvested from the liposomes, radiolabeled, and analyzed by polyacrylamide gel electrophoresis. Encapsulated catalysts represent a model for primitive cellular systems in which an RNA polymerase was entrapped within a protected microenvironment.

Key words

RNA Liposome Biogenesis Origin of life Polynucleotide phosphorylase Polymerase Permeability 



adenosine diphosphate


dimyristoyl phosphatidylcholine


ethylenediaminetetraacetic acid


large unilamellar vesicle


multilamellar vesicle


polyacrylamide gel electrophoresis

PNPase or PNP

polynucleotide phosphorylase


small unilamellar vesicle


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bachmann PA, Luisi PL, Lang J (1992) Autocatalytic self-replicating micelles as models for prebiotic structures. Nature 357:57–59Google Scholar
  2. Chakrabarti AC, Deamer DW (1992) Permeability of lipid bilayers to amino acids and phosphate. Biochim Biophys Acta 1111:171–177Google Scholar
  3. Deamer DW, Barchfeld GL (1982) Encapsulation of macromolecules by lipid vesicles under simulated prebiotic conditions. J Mol Evol 18:203–206Google Scholar
  4. Deamer DW, Bramhall J (1986) Permeability of lipid bilayers to and ionic solutes. Chem Phys Lipids 40:167–188Google Scholar
  5. Deamer DW, Harang Mahon E, Bosco G (in press) Self-assembly and function of primitive membrane structures. In: Early life on earth. Nobel Symposium 84, Columbia, UP, New YorkGoogle Scholar
  6. Evreinova TN, Orlovskii AF, Oparin AI (1975) Action of enzyme polynucleotide phosphorylase in a protein-carbohydrate coacervate system. Dokl Akad Nauk SSSR 220:38–40Google Scholar
  7. Fleischaker GR (1990) Origins of life: an operational definition. Orig Life Evol Biosph 20:127–132Google Scholar
  8. Grunberg-Manago M (1961) Polynucleotide phosphorylase. In: Boyer P et al. (eds) The enzymes. Academic Press, New York, pp 257–280Google Scholar
  9. Hargreaves WR, Deamer DW (1978) Liposomes from ionic, single-chain amphiphiles. Biochemistry 17:3759–3768Google Scholar
  10. Hope MJ, Bally MB, Webb G, Cullis PR (1985) Production of large unilamellar vesicles by an extrusion procedure. Characterization of size distribution, trapped volume and the ability to maintain a membrane potential. Biochim Biophys Acta 812:55–65Google Scholar
  11. Ipsen JH, Jorgensen K, Mouritsen OG (1990) Density fluctuations in saturated phospholipid bilayers increase as acyl-chain length decreases. Biophys J 58:1099–1107Google Scholar
  12. Joyce GF (1989) RNA evolution and the origin of life. Nature 338: 217–224Google Scholar
  13. Morowitz HJ, Heinz B, Deamer DW (1988) The chemical logic of a minimum protocell. Orig Life Evol Biosph 18:281–287Google Scholar
  14. Morowitz HJ (1992) Beginnings of cellular life. Yale University Press, New Haven, CTGoogle Scholar
  15. Nagle JF, Scott HL Jr (1978) Lateral compressibility of lipid mono- and bilayers—theory of membrane permeability. Biochim Biophys Acta 513:236–243Google Scholar
  16. Oparin AI, Orlovskii AF, Ya V, Gladilin KL (1976) Influence of enzymatic synthesis of polyadenylic acid on a coacervate system. Dokl Akad Nauk SSSR 226:61–63Google Scholar
  17. Papahadjopoulos D, Jacobson K, Nir S, Isac T (1973) Phase transitions in phospholipid vesicles. Fluorescence polarization and permeability measurements concerning the effect of temperature and cholesterol. Biochim Biophys Acta 311:330–348Google Scholar

Copyright information

© Springer-Verlag New York Inc 1994

Authors and Affiliations

  • Ajoy C. Chakrabarti
    • 1
  • Ronald R. Breaker
    • 2
  • Gerald F. Joyce
    • 2
  • David W. Deamer
    • 1
  1. 1.Department of Chemistry and BiochemistryUniversity of CaliforniaSanta Cruz, Santa CruzUSA
  2. 2.Departments of Chemistry and Molecular BiologyThe Scripps Research InstituteCALa JollaUSA

Personalised recommendations