A pseudo-phytochelatin synthase in the ciliated protozoan Tetrahymena thermophila |
| |
| Authors: | Francisco Amaro Roberta Ruotolo Ana Martín-González Andrea Faccini Simone Ottonello Juan-Carlos Gutiérrez |
| |
| Affiliation: | 1. Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada;2. Environment Canada, National Wildlife Research Centre, Ottawa, Ontario K1A 0H3, Canada;3. Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA;4. Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada;5. Department of Zoology and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA;6. Department of Biology & Chemistry, City University of Hong Kong, Kowloon, Hong Kong, SAR, China;7. Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA |
| |
| Abstract: | Phytochelatins (PCs) and metallothioneins (MTs) are the two major heavy metal chelating peptides in eukaryotes. We report here on the identification of a biosynthetically inactive pseudo-phytochelatin synthase enzyme (TtψPCS) in the ciliate Tetrahymena thermophila, the first of this kind (pseudo-PCS) to be described in eukaryotes. TtψPCS which resembles a true PCS at the N-terminal region, while it is most divergent in its Cys-poor C-terminal region, was found to be up-regulated under cadmium stress conditions. However, only glutathione (GSH) hydrolysis products, but not PCs, could be detected in extracts from Cd-treated cells. The latter feature is reminiscent of pseudo-PCS enzymes recently identified in cyanobacteria, which are also biosynthetically inactive, but capable to hydrolyze GSH. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
