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Structure of glutathione reductase from escherichia coli at 1.86 Å resolution: Comparison with the enzyme from human erythrocytes
Author(s) -
Mittl Peer R.E.,
Schulz Georg E.
Publication year - 1994
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560030509
Subject(s) - antiparallel (mathematics) , dimer , chemistry , crystallography , cooperativity , escherichia coli , stereochemistry , enzyme , multiple isomorphous replacement , protein structure , active site , biochemistry , peptide sequence , physics , organic chemistry , quantum mechanics , magnetic field , gene
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 Å 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 β‐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.