Structure of a tRNA repair enzyme and molecular biology workhorse: T4 polynucleotide kinase

Eric A. Galburt, John Pelletier, Geoffrey Wilson, Barry L. Stoddard

Research output: Contribution to journalArticlepeer-review

107 Scopus citations


T4 phage polynucleotide kinase (PNK) was identified over 35 years ago and has become a staple reagent for molecular biologists. The enzyme displays 5′-hydroxyl kinase, 3′-phosphatase, and 2′,3′-cyclic phosphodiesterase activities against a wide range of substrates. These activities modify the ends of nicked tRNA generated by a bacterial response to infection and facilitate repair by T4 RNA ligase. DNA repair enzymes that share conserved motifs with PNK have been identified in eukaryotes. PNK contains two functionally distinct structural domains and forms a homotetramer. The C-terminal phosphatase domain is homologous to the L-2-haloacid dehalogenase family and the N-terminal kinase domain is homologous to adenylate kinase. The active sites have been characterized through structural homology analyses and visualization of bound substrate.

Original languageEnglish
Pages (from-to)1249-1260
Number of pages12
Issue number9
StatePublished - Sep 2002


  • Bifunctional enzyme
  • Crystal structure
  • Phosphatase
  • Structural enzymology
  • T4 polynucleotide kinase
  • tRNA repair


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