Nucleotide-mimetic synthetic ligands for DNA-recognizing enzymes One-step purification of Pfu DNA polymerase

J Chromatogr A. 2006 Jul 28;1122(1-2):63-75. doi: 10.1016/j.chroma.2006.04.044. Epub 2006 May 18.

Abstract

The commercial availability of DNA polymerases has revolutionized molecular biotechnology and certain sectors of the bio-industry. Therefore, the development of affinity adsorbents for purification of DNA polymerases is of academic interest and practical importance. In the present study we describe the design, synthesis and evaluation of a combinatorial library of novel affinity ligands for the purification of DNA polymerases (Pols). Pyrococcus furiosus DNA polymerase (Pfu Pol) was employed as a proof-of-principle example. Affinity ligand design was based on mimicking the natural interactions between deoxynucleoside-triphosphates (dNTPs) and the B-motif, a conserved structural moiety found in Pol-I and Pol-II family of enzymes. Solid-phase 'structure-guided' combinatorial chemistry was used to construct a library of 26 variants of the B-motif-binding 'lead' ligand X-Trz-Y (X is a purine derivative and Y is an aliphatic/aromatic sulphonate or phosphonate derivative) using 1,3,5-triazine (Trz) as the scaffold for assembly. The 'lead' ligand showed complementarity against a Lys and a Tyr residue of the polymerase B-motif. The ligand library was screened for its ability to bind and purify Pfu Pol from Escherichia coli extract. One immobilized ligand (oABSAd), bearing 9-aminoethyladenine (AEAd) and sulfanilic acid (oABS) linked on the triazine scaffold, displayed the highest purifying ability and binding capacity (0,55 mg Pfu Pol/g wet gel). Adsorption equilibrium studies with this affinity ligand and Pfu Pol determined a dissociation constant (K(D)) of 83 nM for the respective complex. The oABSAd affinity adsorbent was exploited in the development of a facile Pfu Pol purification protocol, affording homogeneous enzyme (>99% purity) in a single chromatography step. Quality control tests showed that Pfu Pol purified on the B-motif-complementing ligand is free of nucleic acids and contaminating nuclease activities, therefore, suitable for experimental use.

MeSH terms

  • Amino Acid Motifs / genetics
  • Amino Acid Sequence
  • Biomimetics / methods
  • Chromatography, Affinity / instrumentation
  • Chromatography, Affinity / methods
  • Combinatorial Chemistry Techniques / methods
  • DNA Polymerase I / chemistry
  • DNA Polymerase I / genetics
  • DNA Polymerase I / isolation & purification
  • DNA Polymerase II / chemistry
  • DNA Polymerase II / genetics
  • DNA Polymerase II / isolation & purification
  • DNA-Directed DNA Polymerase / chemistry
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / isolation & purification*
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / enzymology
  • Hydrogen-Ion Concentration
  • Ligands
  • Models, Chemical
  • Molecular Sequence Data
  • Molecular Structure
  • Nucleotides / chemical synthesis
  • Nucleotides / chemistry*
  • Protein Structure, Secondary
  • Pyrococcus furiosus / enzymology*
  • Pyrococcus furiosus / genetics
  • Sepharose / analogs & derivatives
  • Sepharose / chemistry
  • Sequence Homology, Amino Acid

Substances

  • Ligands
  • Nucleotides
  • Sepharose
  • Pfu DNA polymerase
  • DNA Polymerase I
  • DNA Polymerase II
  • DNA-Directed DNA Polymerase