HupO, a novel regulator involved in thiosulfate-responsive control of HupSL [NiFe]-hydrogenase synthesis in Thiocapsa roseopersicina

Ildikó K. Nagy, K. Kovács, G. Rákhely, Gergely Maróti

Research output: Contribution to journalArticle

Abstract

[NiFe]-hydrogenases are regulated by various factors to fulfill their physiological functions in bacterial cells. The photosynthetic purple sulfur bacterium Thiocapsa roseopersicina harbors four functional [NiFe]-hydrogenases: HynSL, HupSL, Hox1, and Hox2. Most of these hydrogenases are functionally linked to sulfur metabolism, and thiosulfate has a central role in this organism. The membrane-associated Hup hydrogenases have been shown to play a role in energy conservation through hydrogen recycling. The expression of Hup-type hydrogenases is regulated by H2 in Rhodobacter capsulatus and Cupriavidus necator; however, it has been shown that the corresponding hydrogen-sensing system is nonfunctional in T. roseopersicina and that thiosulfate is a regulating factor of hup expression. Here, we describe the discovery and analysis of mutants of a putative regulator (HupO) of the Hup hydrogenase in T. roseopersicina. HupO appears to mediate the transcriptional repression of Hup enzyme synthesis under low-thiosulfate conditions. We also demonstrate that the presence of the Hox1 hydrogenase strongly influences Hup enzyme synthesis in that hup expression was decreased significantly in the hox1 mutant. This reduction in Hup synthesis could be reversed by mutation of hupO, which resulted in strongly elevated hup expression, as well as Hup protein levels, and concomitant in vivo hydrogen uptake activity in the hox1 mutant. However, this regulatory control was observed only at low thiosulfate concentrations. Additionally, weak hydrogen-dependent hup expression was shown in the hupO mutant strain lacking the Hox1 hydrogenase. HupO-mediated Hup regulation therefore appears to link thiosulfate metabolism and the hydrogenase network in T. roseopersicina.

Original languageEnglish
Pages (from-to)2039-2049
Number of pages11
JournalApplied and Environmental Microbiology
Volume82
Issue number7
DOIs
Publication statusPublished - Apr 1 2016

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Thiocapsa roseopersicina
ferredoxin hydrogenase
Hydrogenase
Thiosulfates
thiosulfates
thiosulfate
synthesis
hydrogen
Hydrogen
metabolism
sulfur
mutants
enzyme
Enzyme Repression
Chromatiaceae
Cupriavidus necator
energy conservation
Rhodobacter capsulatus
mutation
harbor

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Food Science
  • Biotechnology
  • Ecology

Cite this

HupO, a novel regulator involved in thiosulfate-responsive control of HupSL [NiFe]-hydrogenase synthesis in Thiocapsa roseopersicina. / Nagy, Ildikó K.; Kovács, K.; Rákhely, G.; Maróti, Gergely.

In: Applied and Environmental Microbiology, Vol. 82, No. 7, 01.04.2016, p. 2039-2049.

Research output: Contribution to journalArticle

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