Characterization of thiosulfate reductase from Pyrobaculum aerophilum heterologously produced in Pyrococcus furiosus

Dominik K. Haja, Chang Hao Wu, Farris L. Poole, John Sugar, Samuel G. Williams, Anne K. Jones, Michael W.W. Adams

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

The genome of the archaeon Pyrobaculum aerophilum (Topt ~ 100 °C) contains an operon (PAE2859–2861) encoding a putative pyranopterin-containing oxidoreductase of unknown function and metal content. These genes (with one gene modified to encode a His-affinity tag) were inserted into the fermentative anaerobic archaeon, Pyrococcus furiosus (Topt ~ 100 °C). Dye-linked assays of cytoplasmic extracts from recombinant P. furiosus show that the P. aerophilum enzyme is a thiosulfate reductase (Tsr) and reduces thiosulfate but not polysulfide. The enzyme (Tsr–Mo) from molybdenum-grown cells contains Mo (Mo:W = 9:1) while the enzyme (Tsr–W) from tungsten-grown cells contains mainly W (Mo:W = 1:6). Purified Tsr–Mo has over ten times the activity (Vmax = 1580 vs. 141 µmol min−1 mg−1) and twice the affinity for thiosulfate (Km = ~ 100 vs. ~ 200 μM) than Tsr–W and is reduced at a lower potential (Epeak = − 255 vs − 402 mV). Tsr–Mo and Tsr–W proteins are heterodimers lacking the membrane anchor subunit (PAE2861). Recombinant P. furiosus expressing P. aerophilum Tsr could not use thiosulfate as a terminal electron acceptor. P. furiosus contains five pyranopterin-containing enzymes, all of which utilize W. P. aerophilum Tsr–Mo is the first example of an active Mo-containing enzyme produced in P. furiosus.

Original languageEnglish (US)
Pages (from-to)53-62
Number of pages10
JournalExtremophiles
Volume24
Issue number1
DOIs
StatePublished - Jan 1 2020

Keywords

  • Archaea
  • Hyperthermophiles
  • Metabolism
  • Metalloenzyme
  • Pyranopterin
  • Recombinant proteins

ASJC Scopus subject areas

  • Microbiology
  • Molecular Medicine

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