Structure of glutathione reductase from Escherichia coli at 1.86 A resolution: comparison with the enzyme from human erythrocytes

Protein Sci. 1994 May;3(5):799-809. doi: 10.1002/pro.5560030509.

Abstract

The crystal structure of the dimeric flavoenzyme glutathione reductase from Escherichia coli was determined and refined to an R-factor of 16.8% at 1.86 A resolution. The molecular 2-fold axis of the dimer is local but very close to a possible crystallographic 2-fold axis; the slight asymmetry could be rationalized from the packing contacts. The 2 crystallographically independent subunits of the dimer are virtually identical, yielding no structural clue on possible cooperativity. The structure was compared with the well-known structure of the homologous enzyme from human erythrocytes with 52% sequence identity. Significant differences were found at the dimer interface, where the human enzyme has a disulfide bridge, whereas the E. coli enzyme has an antiparallel beta-sheet connecting the subunits. The differences at the glutathione binding site and in particular a deformation caused by a Leu-Ile exchange indicate why the E. coli enzyme accepts trypanothione much better than the human enzyme. The reported structure provides a frame for explaining numerous published engineering results in detail and for guiding further ones.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Crystallization
  • Crystallography, X-Ray
  • Erythrocytes / enzymology*
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Glutathione Reductase / blood
  • Glutathione Reductase / chemistry*
  • Glutathione Reductase / genetics
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Structure
  • Protein Conformation
  • Protein Structure, Secondary
  • Solvents
  • Species Specificity
  • Water / chemistry

Substances

  • Solvents
  • Water
  • Glutathione Reductase