Abstract
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.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- ADP:
-
adenosine diphosphate
- DMPC:
-
dimyristoyl phosphatidylcholine
- EDTA:
-
ethylenediaminetetraacetic acid
- LUV:
-
large unilamellar vesicle
- MLV:
-
multilamellar vesicle
- PAGE:
-
polyacrylamide gel electrophoresis
- PNPase or PNP:
-
polynucleotide phosphorylase
- SUV:
-
small unilamellar vesicle
references
Bachmann PA, Luisi PL, Lang J (1992) Autocatalytic self-replicating micelles as models for prebiotic structures. Nature 357:57–59
Chakrabarti AC, Deamer DW (1992) Permeability of lipid bilayers to amino acids and phosphate. Biochim Biophys Acta 1111:171–177
Deamer DW, Barchfeld GL (1982) Encapsulation of macromolecules by lipid vesicles under simulated prebiotic conditions. J Mol Evol 18:203–206
Deamer DW, Bramhall J (1986) Permeability of lipid bilayers to and ionic solutes. Chem Phys Lipids 40:167–188
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 York
Evreinova TN, Orlovskii AF, Oparin AI (1975) Action of enzyme polynucleotide phosphorylase in a protein-carbohydrate coacervate system. Dokl Akad Nauk SSSR 220:38–40
Fleischaker GR (1990) Origins of life: an operational definition. Orig Life Evol Biosph 20:127–132
Grunberg-Manago M (1961) Polynucleotide phosphorylase. In: Boyer P et al. (eds) The enzymes. Academic Press, New York, pp 257–280
Hargreaves WR, Deamer DW (1978) Liposomes from ionic, single-chain amphiphiles. Biochemistry 17:3759–3768
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 812:55–65
Ipsen JH, Jorgensen K, Mouritsen OG (1990) Density fluctuations in saturated phospholipid bilayers increase as acyl-chain length decreases. Biophys J 58:1099–1107
Joyce GF (1989) RNA evolution and the origin of life. Nature 338: 217–224
Morowitz HJ, Heinz B, Deamer DW (1988) The chemical logic of a minimum protocell. Orig Life Evol Biosph 18:281–287
Morowitz HJ (1992) Beginnings of cellular life. Yale University Press, New Haven, CT
Nagle JF, Scott HL Jr (1978) Lateral compressibility of lipid mono- and bilayers—theory of membrane permeability. Biochim Biophys Acta 513:236–243
Oparin AI, Orlovskii AF, Ya V, Gladilin KL (1976) Influence of enzymatic synthesis of polyadenylic acid on a coacervate system. Dokl Akad Nauk SSSR 226:61–63
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 311:330–348
Author information
Authors and Affiliations
Additional information
Correspondence to.: A.C. Chakrabarti
Rights and permissions
About this article
Cite this article
Chakrabarti, A.C., Breaker, R.R., Joyce, G.F. et al. Production of RNA by a polymerase protein encapsulated within phospholipid vesicles. J Mol Evol 39, 555–559 (1994). https://doi.org/10.1007/BF00160400
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00160400