The structure of I-Crel, a group I intron-encoded homing endonuclease

Nat Struct Biol. 1997 Jun;4(6):468-76. doi: 10.1038/nsb0697-468.

Abstract

The structure of I-Crel provides the first view of a protein encoded by a gene within an intron. This endonuclease recognizes a long DNA site approximately 20 base pairs in length and facilitates the lateral transfer of that intron. The protein exhibits a DNA-binding surface consisting of four antiparallel beta-strands that form a 20 A wide groove which is over 70 A long. The architecture of this fold is different from that of the TATA binding protein, TBP, which also contains an antiparallel beta-saddle. The conserved LAGLIDADG motif, which is found in many mobile intron endonucleases, maturases and inteins, forms a novel helical interface and contributes essential residues to the active site.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Conserved Sequence
  • Crystallography, X-Ray
  • DNA / metabolism*
  • DNA Restriction Enzymes*
  • Deoxyribonuclease EcoRI / chemistry
  • Deoxyribonuclease EcoRI / metabolism
  • Deoxyribonucleases, Type II Site-Specific / chemistry*
  • Deoxyribonucleases, Type II Site-Specific / genetics
  • Deoxyribonucleases, Type II Site-Specific / metabolism*
  • Dimerization
  • Eukaryotic Cells / enzymology
  • Introns*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Protein Folding
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Substrate Specificity

Substances

  • Recombinant Proteins
  • DNA
  • DNA Restriction Enzymes
  • Deoxyribonuclease EcoRI
  • endodeoxyribonuclease CreI
  • Deoxyribonucleases, Type II Site-Specific