A covalent complex between retroviral integrase and nicked substrate DNA

Michael Katzman, Joseph P G Mack, Anna Marie Skalka, Jonathan Leis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Purified retroviral integrase (IN) from avian sarcoma-leukosis viruses can appropriately process the termini of linear viral DNA, cleave host DNA in a sequence-independent manner, and catalyze integrative recombination; an exogenous source of energy is not required for these reactions. Using DNA substrates containing radioactive phosphate groups, we demonstrate that IN becomes covalently joined to the new 5′ phosphate ends of DNA produced at sites of cleavage. Most of the phosphodiester linkages between IN and DNA involve serine, but some involve threonine. Computer-assisted alignment of 80 retroviral and retrotransposon IN sequences identified one serine that is conserved in all of these proteins and three less-conserved threonine residues. These results identify candidate active-site residues and provide support for the participation of a covalent IN-DNA intermediate in retroviral integration.

Original languageEnglish (US)
Pages (from-to)4695-4699
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number11
StatePublished - Jun 1 1991


  • Covalent linkage
  • Retroviral DNA integration

ASJC Scopus subject areas

  • General


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