title: Conserved structural elements in glutathione transferase homologues encoded in the genome of Escherichia coli.
abstract: Multiple sequence alignments of the eight glutathione (GSH) transferase homologues encoded in the genome of Escherichia coli were used to define a consensus sequence for the proteins. The consensus sequence was analyzed in the context of the three-dimensional structure of the gst gene product (EGST) obtained from two different crystal forms of the enzyme. The enzyme consists of two domains. The N-terminal region (domain I) has a thioredoxin-like alpha/beta-fold, while the C-terminal domain (domain II) is all alpha-helical. The majority of the consensus residues (12/17) reside in the N-terminal domain. Fifteen of the 17 residues are involved in hydrophobic core interactions, turns, or electrostatic interactions between the two domains. The results suggest that all of the homologues retain a well-defined group of structural elements both in and between the N-terminal alpha/beta domain and the C-terminal domain. The conservation of two key residues for the recognition motif for the gamma-glutamyl-portion of GSH indicates that the homologues may interact with GSH or GSH analogues such as glutathionylspermidine or alpha-amino acids. The genome context of two of the homologues forms the basis for a hypothesis that the b2989 and yibF gene products are involved in glutathionylspermidine and selenium biochemistry, respectively.
authors.affiliation: Department of Biochemistry and the Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville Tennessee 37232-0146, USA.
authors.forename: Chris L
authors.initials: CL
authors.lastname: Rife
authors.forename: James F
authors.initials: JF
authors.lastname: Parsons
authors.forename: Gaoyi
authors.initials: G
authors.lastname: Xiao
authors.forename: Gary L
authors.initials: GL
authors.lastname: Gilliland
authors.forename: Richard N
authors.initials: RN
authors.lastname: Armstrong
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics*; D016680:Genome, Bacterial; D005982:Glutathione Transferase / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D029968:Escherichia coli Proteins; D005982:Glutathione Transferase