3-mercaptopyruvate sulfurtransferase of leishmania contains an unusual C-terminal extension and is involved in thioredoxin and antioxidant metabolism

Roderick A. M. Williams, Sharon M. Kelly, Jeremy C. Mottram, Graham H. Coombs

Research output: Contribution to journalArticlepeer-review

64 Citations (Scopus)

Abstract

Cytosolic 3-mercaptopyruvate sulfurtransferases (EC ) of Leishmania major and Leishmania mexicana have been cloned, expressed as active enzymes in Escherichia coli, and characterized. The leishmanial single-copy genes predict a sulfurtransferase that is structurally peculiar in possessing a C-terminal domain of some 70 amino acids. Homologous genes of Trypanosoma cruzi and Trypanosoma brucei encode enzymes with a similar C-terminal domain, suggesting that this feature, not known in any other sulfurtransferase, is a characteristic of trypanosomatid parasites. Short truncations of the C-terminal domain resulted in misfolded inactive proteins, demonstrating that the domain plays some key role in facilitating correct folding of the enzymes. The leishmanial recombinant enzymes exhibited high activity toward 3-mercaptopyruvate and catalyzed the transfer of sulfane sulfur to cyanide to form thiocyanate. They also used thiosulfate as a substrate and reduced thioredoxin as the accepting nucleophile, the latter being oxidized. The enzymes were expressed in all life cycle stages, and the expression level was increased under peroxide or hypo-sulfur stress. The results are consistent with the enzymes having an involvement in the synthesis of sulfur amino acids per se or iron-sulfur centers of proteins and the parasite's management of oxidative stress.

Original languageEnglish
Pages (from-to)1480-1486
Number of pages7
JournalJournal of Biological Chemistry
Volume278
Issue number3
DOIs
Publication statusPublished - 17 Jan 2003
Externally publishedYes

Keywords

  • Amino Acid Sequence
  • Animals
  • Antioxidants
  • Base Sequence
  • Cloning, Molecular
  • DNA Primers
  • Leishmania major
  • Leishmania mexicana
  • Molecular Sequence Data
  • Oxidation-Reduction
  • Polymerase Chain Reaction
  • Protein Denaturation
  • Protein Folding
  • Recombinant Proteins
  • Sequence Homology, Amino Acid
  • Sulfurtransferases
  • Thioredoxins

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