Single-step purification of recombinant Thermus aquaticus DNA polymerase using DNA-aptamer immobilized novel affinity magnetic beads

Biotechnol Prog. 2007 Jan-Feb;23(1):146-54. doi: 10.1021/bp0602505.

Abstract

A DNA aptamer specific for Thermus aquaticus DNA polymerase (Taq-polymerase) was immobilized on magnetic beads, which were prepared in the presented study. The effect of various parameters including pH, temperaturem and aptamer concentration on the immobilization of 5'-thiol labeled DNA-aptamer onto glutaric dialdhyde activated magnetic beads was evaluated. The binding conditions of Taq-polymerase on the aptamer immobilized magnetic beads were studied using commercial Taq-polymerase to characterize the surface complexation reaction. Efficiency of affinity magnetic beads in the purification of recombinant Taq-polymerase from crude extracts was also evaluated. For this case, the enzyme "recombinant Taq-DNA polymerase" was cloned and expressed using an Amersham E. coli GST-Gene Fusion Expression system. Crude extracts were in contact with affinity magnetic beads for 30 min and were collected by magnetic field application. The purity of the eluted Tag-polymerase from the affinity beads, as determined by HPLC, was 93% with a recovery of 89% in a one-step purification protocol. Apparently, the system was found highly effective as one step for the low-cost purification of Taq-polymerase in bacterial crude extract.

MeSH terms

  • Aptamers, Nucleotide / chemistry*
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / isolation & purification*
  • DNA-Directed DNA Polymerase / metabolism*
  • Enzymes, Immobilized / chemistry
  • Escherichia coli / physiology
  • Immunomagnetic Separation / methods*
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Thermus / enzymology*
  • Thermus / genetics*

Substances

  • Aptamers, Nucleotide
  • Enzymes, Immobilized
  • Recombinant Proteins
  • DNA-Directed DNA Polymerase