Cytoplasmic Localization of Sulfide:Quinone Oxidoreductase and Persulfide Dioxygenase of Cupriavidus pinatubonensis JMP134

Abstract

Heterotrophic bacteria have recently been reported to oxidize sulfide to sulfite and thiosulfate by using sulfide:quinone oxidoreductase (SQR) and persulfide dioxygenase (PDO). In chemolithotrophic bacteria, both SQR and PDO have been reported to function in the periplasmic space, with SQR as a peripheral membrane protein whose C terminus inserts into the cytoplasmic membrane and PDO as a soluble protein. JMP134, best known for its ability to degrade 2,4-dichlorophenoxyacetic acid and other aromatic pollutants, has a gene cluster of and encoding SQR (CpSQR) and CpPDO2. When cloned in , the enzymes are functional. Here we investigated whether they function in the periplasmic space or in the cytoplasm in heterotrophic bacteria. By using sequence analysis, biochemical detection, and green fluorescent protein (GFP)/PhoA fusion proteins, we found that CpSQR was located on the cytoplasmic side of the membrane and CpPDO2 was a soluble protein in the cytoplasm with a tendency to be peripherally located near the membrane. The location proximity of these proteins near the membrane in the cytoplasm may facilitate sulfide oxidation in heterotrophic bacteria. The information may guide the use of heterotrophic bacteria in bioremediation of organic pollutants as well as HS. Sulfide (HS, HS, and S), which is common in natural gas and wastewater, causes a serious malodor at low levels and is deadly at high levels. Microbial oxidation of sulfide is a valid bioremediation method, in which chemolithotrophic bacteria that use sulfide as the energy source are often used to remove sulfide. Heterotrophic bacteria with SQR and PDO have recently been reported to oxidize sulfide to sulfite and thiosulfate. JMP134 has been extensively characterized for its ability to degrade organic pollutants, and it also contains SQR and PDO. This paper shows the localization of SQR and PDO inside the cytoplasm in the vicinity of the membrane. The information may provide guidance for using heterotrophic bacteria in sulfide bioremediation.

Sulfur Oxidation in the Acidophilic Autotrophic Acidithiobacillus spp.

“…(Valdés et al, 2008a; Quatrini et al, 2009; Mangold et al, 2011; Chen et al, 2012; Yin et al, 2014; Christel et al, 2016). Similar localization of SQR was reported for Rhodobacter capsulatus (Schutz et al, 1999), while results for heterotrophic Cupriavidus pinatubonensis indicated that SQR located on the cytoplasmic side of the membrane and the soluble cytoplasmic PDO was in the vicinity of the membrane (Gao et al, 2017). The close location of SQR and PDO in the cytoplasm increases the efficiency of sulfide oxidation in heterotrophic bacteria (Gao et al, 2017).…”

Rhodaneses minimize the accumulation of cellular sulfane sulfur to avoid disulfide stress during sulfide oxidation in bacteria

“…The activity of SQR Cp relies on the electron transport chain in cell membrane [ 40 , 41 ], and the prepared crude membrane fraction was sufficient to detect SQR activity [ 42 ]. In order to maintain the SQR Cp activity as in native state, the membrane factions of SQR Cp or SQR Cp -C94S proteins overexpression cells were extracted to characterize the enzyme activity in all the biochemical assay in vitro.…”

Physiology, Taxonomy, and Sulfur Metabolism of the Sulfolobales, an Order of Thermoacidophilic Archaea

“…Sulfides (S 2− , HS − , and H 2 S) are widely distributed in soils, ore, wastewater, and marine environments. They are produced partly from mineral deposits, and partly by biological metabolism, including as products of eukaryotic and prokaryotic endogenous catabolism of cysteine and iron–sulfur proteins and dissimilatory metabolism of sulfur-containing inorganic compounds ( Kabil and Banerjee, 2010 ; Lencina et al, 2013 ; Gao et al, 2017 ; Bełtowski, 2019 ). H 2 S is an important electron donor in prokaryotes, such as phototrophic or chemotrophic microorganisms ( Reinartz et al, 1998 ; Sakurai et al, 2010 ; Klatt et al, 2015 ).…”