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

Nagy, Ildikó Katalin and Kovács, Kornél Lajos and Rákhely, Gábor and Maróti, Gergely (2016) HupO is a novel regulator involved in thiosulfate-responsive control of HupSL NiFe-hydrogenase synthesis in Thiocapsa roseopersicina. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 82 (7). pp. 2039-2049. ISSN 0099-2240


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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, where 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 non-functional in T. roseopersicina and that thiosulfate was a regulating factor of the hup expression. Here, we describe the discovery and mutant analysis of a putative regulator (HupO) of the Hup hydrogenase in T. roseopersicina. HupO appears to mediate transcriptional repression of Hup enzyme synthesis under low thiosulfate concentrations. We also demonstrate that the presence of the Hox1 hydrogenase strongly influences Hup enzyme synthesis, whereby hup expression was decreased significantly in the hox1 mutant. This reduction in Hup synthesis could be reverted 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 only observed at low thiosulfate concentration. 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.

Item Type: Article
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia > QH3011 Biochemistry / biokémia
Q Science / természettudomány > QR Microbiology / mikrobiológia
Depositing User: MTMT SWORD
Date Deposited: 03 Feb 2017 12:41
Last Modified: 08 Feb 2017 14:27

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