Selenocysteine incorporation in Kinetoplastid: selenophosphate synthetase (SELD) from Leishmania major and Trypanosoma brucei.

摘要: Selenophosphate synthetase (EC 2.7.9.3), the product of selD gene, produces biologically active selenium donor compound, monoselenophosphate, from ATP and selenide, for synthesis selenocysteine. The kinetoplastid Leishmania major Trypanosoma brucei genes were cloned SELD protein overexpressed purified to apparent homogeneity. gene in L. T. are respectively 1197 1179 bp long encoding proteins 399 393 amino acids with molecular masses 42.7 43 kDa. mass 100 kDa both (L. brucei) SELDs is consistent dimeric proteins. complement Escherichia coli (WL400) deletion confirming it a functional enzyme specific activity these enzymes was determined. A conserved Cys residue identified by multiple sequence alignment as well complementation assay mutant (Cys Ala) forms identifying this essential catalytic function.