Genetic Identification of Antimonate Respiratory Reductase in Shewanella sp. ANA-3

Abstract

Microbial antimonate [Sb(V)] respiratory reduction is an important process regulating Sb redox transformation in the environment. However, little is known about the microbial respiratory reductase for Sb(V). Herein, we report Sb(V)-respiring reduction by Shewanella sp. ANA-3 through an arsenate respiratory reductase encoded by arrAB. Incubation experiments showed that Shewanella sp. ANA-3 mediated Sb(V)-respiring reduction, which was dependent on the cell concentration. Both protein analysis and reverse transcriptase−polymerase chain reaction results revealed that arrAB was highly expressed in Sb(V)-respiring reduction. In vivo evidence with mutants indicated that neither ANA-3-ΔarrA nor ANA-3-ΔarrB was capable of reducing Sb(V) as efficiently as the wild type, whereas complementation by the wild-type sequences of arrA and arrB rescued the mutants' ability. Our in vitro results showed that ArrAB purified by His-Tag was able to mediate Sb(V) reduction, though with much suppressed catalytic kinetics compared with As(V) reduction. The cell-concentration-dependent reduction of Sb(V) was regulated by quorum sensing via the luxS gene. This study opens a new chapter in the mechanistic understanding of microbial Sb(V) respiratory reduction.

Identification of Antimonate Reducing Bacteria and Their Potential Metabolic Traits by the Combination of Stable Isotope Probing and Metagenomic-Pangenomic Analysis

“…ANA-3 through an arsenate respiratory reductase encoded by arrAB. 61 In this study, the shift of arrA to heavier fractions in 13 CSb also implied that SbRB may contain an arrA. Consistently, arrA was detected in all three Geobacter-associated bins but not in other bins.…”

“…Given the chemical structural similarities between As and Sb, microorganisms may use similar metabolic pathways to transform both As and Sb. Indeed, the arrA gene encoding arsenate reductase could also contribute to the reduction of Sb­(V). , For example, Wang et al reported Sb­(V) reduction by Shewanella sp. ANA-3 through an arsenate respiratory reductase encoded by arrAB .…”

“…Indeed, the arrA gene encoding arsenate reductase could also contribute to the reduction of Sb­(V). , For example, Wang et al reported Sb­(V) reduction by Shewanella sp. ANA-3 through an arsenate respiratory reductase encoded by arrAB . In this study, the shift of arrA to heavier fractions in 13 CSb also implied that SbRB may contain an arrA .…”

“…Indeed, the arrA gene encoding arsenate reductase could also contribute to the reduction of Sb(V). 14,61 For example, Wang et al reported Sb(V) reduction by Shewanella sp. ANA-3 through an arsenate respiratory reductase encoded by arrAB.…”

New Mobilization Pathway of Antimonite: Thiolation and Oxidation by Dissimilatory Metal-Reducing Bacteria via Elemental Sulfur Respiration

“…Antimony (Sb), a toxic contaminant, has received public attention due to increased industrial use and mining activities. , The fate of Sb is mediated by microorganisms, and a wide range of bacteria have been reported to promote or inhibit Sb release. , Dissimilatory metal-reducing bacteria (DMRB) including Shewanella and Geobacter spp., widely distributed in Sb-contaminated environments, − have been reported to affect Sb mobility under anoxic conditions. , …”