FINGERPRINT ANALYSIS OF SELECTED GLUTATHIONE S-TRANSFERASE SUPERFAMILY GENES FROM RAPE (BRASSICA NAPUS)

The glutathione S-transferases (GSTs; EC 2.5.1.18) are a widely distributed family of detoxifying dimeric enzymes found in both invertebrates and vertebrates, plants, yeast and bacteria. GSTs catalyze the nucleophilic addition of glutathione (GSH) to the electrophilic groups of a large variety of hydrophobic toxic chemicals. Following their uptake, the conjugation of such molecules to GSH increases their solubility and facilitates their further metabolic processing. In plants, the conjugated products are either sequestered in the vacuole or transferred to the apoplast thus potentially contributing to reclaim cells from unwanted compounds. It is well documented that plant GSTs show major transcriptional regulation as the levels of their transcripts markedly increase in response to a wide variety of stressful conditions, such as herbicides, chilling, hypoxic stress, dehydration, wounding and pathogen attack. However, the regulation of existing GSTs (post-translational regulation) by reversible covalent modification is still poorly investigated. This in silico study was designed to identify the putative correlation between structural and functional charac¬teristics of plant GST classes belonging to Brassica napus. Consequently, the protein sequences of the expressed GSTs have been retrieved from UniGene, classified and then analyzed in order to assess the evolutionary trend. Moreover, the fingerprint analysis was performed with SCAN Prosite in the attempt to correlate meaningful signature profile and biological information. The fingerprint analysis revealed that specific signature profiles related mainly to protein phosphorylation are in the GST classes thus suggesting that they might be subjected to reversible activation by phosphorylation-mediated regulation. This approach provides the knowledge of the relationship between the presence of conserved signature profile and biological function in the view of future selection of GSTs which might be employed in either mutagenesis or genetic transformation studies.