The key role of E418 carboxyl group in the formation of Nt.BspD6I nickase active site: Structural and functional properties of Nt.BspD6I E418A mutant

J Struct Biol. 2020 Jun 1;210(3):107508. doi: 10.1016/j.jsb.2020.107508. Epub 2020 Apr 13.


The mutated nickase Nt.BspD6I E418A has been obtained by site-directed mutagenesis. The purified protein has been crystallized, and its spatial structure has been determined at 2.45 Å resolution. An analysis of the crystal structures of the wild-type and mutated nickase have shown that the elimination of a carboxyl group due to the E418A mutation initiates marked conformational changes in both the N-terminal recognition domain and the C-terminal catalytic domain of nickase and insignificantly affects its linker domain. This is supported by changes in the functional properties of mutated nickase: an increase in the oligomerization capacity in the presence of a substrate, a reduction in the capacity to bind a substrate, and complete loss of catalytic activity.

Keywords: Cleavage domain; Crystal structure; Nickase; Recognition domain; Site-directed mutagenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalytic Domain / genetics
  • Deoxyribonuclease I / chemistry*
  • Deoxyribonuclease I / genetics
  • Deoxyribonuclease I / metabolism*
  • Mutagenesis, Site-Directed
  • Mutation / genetics


  • Deoxyribonuclease I