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
Article

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.

Key words

RNA Liposome Biogenesis Origin of life Polynucleotide phosphorylase Polymerase Permeability 

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

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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

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