title: Overexpression of genes involved in phytochelatin biosynthesis in Escherichia coli: effects on growth, cadmium accumulation and thiol level.
abstract: In Escherichia coli, heterologous production of Schizosaccharomyces pombe phytochelatin synthase (PCS) along with overproduction of E. coli serine acetyltransferase (SAT) and gamma-glutamylcysteine synthase (gammaECS) was achieved and resulted in the accumulation of phytochelatins in bacterial cells. Overproduction of either gammaECS alone or simultaneous production of all three proteins in bacterial cells were accompanied by reduced growth rate in liquid cultures. Interestingly, bacteria overproducing either gammaECS or both SAT and gammaECS (with elevated level of gamma-glutamylcysteine but not of phytochelatins) were able to accumulate more cadmium per dry weight than the control. However, the most efficient cadmium accumulation was observed in bacteria with elevated levels of all three proteins: SAT, gammaECS and PCS. Therefore, "pushing" the entire pathway might be the most promising approach in modification of bacteria for potential bioremediation purposes because the level of intermediates, cysteine and glutathione, can limit the rate of production of phytochelatins. However, in such bacteria other metabolic process might become limiting for efficient growth.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Wawrzyńska
authors.forename: Adam
authors.initials: A
authors.lastname: Wawrzyński
authors.forename: Dali
authors.initials: D
authors.lastname: Gaganidze
authors.forename: Edyta
authors.initials: E
authors.lastname: Kopera
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Piatek
authors.forename: Wojciech
authors.initials: W
authors.lastname: Bal
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Sirko
mesh_terms: D000123:Acetyltransferases / Q000235:genetics; D019881:Aminoacyltransferases / Q000096:biosynthesis; D002104:Cadmium / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D005721:Glutamate-Cysteine Ligase / Q000235:genetics; D005978:Glutathione; D008667:Metalloproteins / Q000096:biosynthesis* / Q000235:genetics; D054811:Phytochelatins; D010957:Plasmids; D012333:RNA, Messenger / Q000235:genetics; D012568:Schizosaccharomyces / Q000201:enzymology; D051050:Serine O-Acetyltransferase; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D014170:Transformation, Genetic
chemical_list: D008667:Metalloproteins; D012333:RNA, Messenger; D013438:Sulfhydryl Compounds; D002104:Cadmium; D054811:Phytochelatins; D000123:Acetyltransferases; D051050:Serine O-Acetyltransferase; D019881:Aminoacyltransferases; C093784:glutathione gamma-glutamylcysteinyltransferase; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione