Dipartimento di Scienze delle Produzioni Agrarie e Alimentari (DISPA), Università di Catania, Via S. Sofia 98, Catania, Italy.
Biodegradation. 2013 Jul;24(4):471-85. doi: 10.1007/s10532-012-9604-3. Epub 2012 Nov 15.
The use of plants to reclaim contaminated soils and groundwater, known as phytoremediation, is a promising biotechnological strategy which has gained a lot of attention in the last few years. Plants have evolved sophisticated detoxification systems against the toxin chemicals: following the uptake, the compounds are activated so that certain functional groups can conjugate hydrophilic molecules, such as thiols. The resulting conjugates are recognized by the tonoplast transporters and sequestered into the vacuoles. The xenobiotic conjugation with glutathione is mediated by enzymes which belong to the superfamily of glutathione S-transferases (GSTs) catalyzing the nucleophylic attack of the sulphur of glutathione on the electrophilic groups of the cytotoxic substrates therefore playing a crucial role in their degradation. This study was designed to identify the putative correlation between structural and functional characteristics of plant GST classes belonging to different plant species. Consequently, the protein sequences of the expressed GSTs have been retrieved from UniGene, classified and then analyzed in order to assess the evolutionary trend and to predict secondary structure. Moreover, the fingerprint analysis was performed with SCAN Prosite in the attempt to correlate meaningful signature profile and biological information. The results evidenced that all the soluble GSTs have a tendency to assume the α-helix secondary structure followed by random coil and β-sheet. The fingerprint analysis revealed that specific signature profiles related mainly to protein phosphorylation are in the GST classes of all considered species thus suggesting that they might be subjected to reversible activation by phosphorylation-mediated regulation. This approach provides the knowledge of the relationship between 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 engineering studies.
利用植物来修复受污染的土壤和地下水，即植物修复，是一种很有前途的生物技术策略，近年来受到了广泛关注。植物已经进化出了复杂的解毒系统来对抗毒素化学物质：在吸收之后，化合物被激活，这样某些功能基团就可以与亲水性分子（如硫醇）结合。由此产生的共轭物被液泡膜转运蛋白识别，并隔离到液泡中。外源化合物与谷胱甘肽的共轭是由属于谷胱甘肽 S-转移酶（GSTs）超家族的酶介导的，该酶催化谷胱甘肽的硫原子对细胞毒性底物的亲电基团的亲核攻击，因此在其降解中起着至关重要的作用。本研究旨在确定属于不同植物物种的植物 GST 类的结构和功能特征之间的假定相关性。因此，从 UniGene 中检索到表达 GST 的蛋白质序列，对其进行分类，然后进行分析，以评估进化趋势并预测二级结构。此外，还使用 SCAN Prosite 进行了指纹分析，试图将有意义的特征图谱和生物学信息相关联。结果表明，所有可溶性 GST 都有倾向于形成α-螺旋二级结构，其次是无规卷曲和β-折叠。指纹分析表明，与蛋白质磷酸化有关的特定特征图谱主要存在于所有考虑的物种的 GST 类中，这表明它们可能通过磷酸化介导的调节而发生可逆激活。这种方法提供了在未来选择 GST 时，关于保守特征图谱与生物学功能之间关系的知识，这些 GST 可能用于诱变或遗传工程研究。
