Is crab duplex-specific nuclease a member of the Serratia family of non-specific nucleases?

Gene. 2008 Jul 15;418(1-2):41-8. doi: 10.1016/j.gene.2008.04.005. Epub 2008 Apr 16.


Kamchatka crab duplex-specific nuclease (Par_DSN) has been classified as a member of the family of DNA/RNA non-specific beta-beta-alpha metal finger (bba-Me-finger) nucleases, the archetype of which is the nuclease from Serratia marcescens. Although the enzyme under investigation seems to belong to the family of S. marcescens nucleases, Par_DSN exhibits a marked preference for double-stranded DNA as a substrate and this property is unusual for other members of this family. We have searched other Arthropod species and identified a number of novel Par_DSN homologs. A phylogenetic analysis demonstrates that the Par_DSN-like enzymes constitute a separate branch in the evolutionary tree of bba-Me-finger nucleases. Combining sequence analysis and site-directed mutagenesis, we found that Par_DSN and its homologs possess the nuclease domain that is slightly longer than that of classic Serratia relatives. The active site composition of Par_DSN is similar but not identical to that of classic Serratia nucleases. Based on these findings, we proposed a new classification of Par_DSN-like nucleases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Brachyura / enzymology*
  • Deoxyribonucleases / chemistry*
  • Deoxyribonucleases / classification*
  • Molecular Structure
  • Mutagenesis, Site-Directed
  • Phylogeny
  • Protein Structure, Tertiary
  • Serratia / enzymology*


  • Deoxyribonucleases