Drosophila glutathione S-transferases have sequence homology to the stringent starvation protein of Escherichia coli.

The Drosophila glutathione S-transferase D genes encode a family of isozymes. We have determined the amino acid sequence of a new member of this family by nucleotide sequence analysis of a genomic DNA clone. The open reading frame of this intronless gene should encode an isozyme subunit of 211 amino acids. This sequence has significant homology to the E. coli stringent starvation protein, SSP, which is also a protein of two identical 211 amino acid subunits. The two proteins have very similar overall amino acid composition as well. It is possible that SSP may be a glutathione S-transferase(s) in E. coli or is evolutionarily related to glutathione S-transferases. Because SSP is known to be tightly associated with the RNA polymerase holoenzyme during purification, it is conceivable that Drosophila glutathione S-transferase(s) may potentially interact with the transcription machinery in a fashion similar to SSP's interaction with E. coli RNA polymerase holoenzyme.