A Minimal Membrane Metal Transport System: Dynamics and Energetics of <i>mer</i> Proteins

Hwang, Hyea; Hazel, Anthony; Lian, Peng; Smith, Jeremy C.; Gumbart, James C.; Parks, Jerry M.

doi:10.1002/jcc.26098

Cited by 5 publications

(4 citation statements)

References 50 publications

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“…In the bacterial mercurial compounds detoxification system, organomercurial lyase (MerB) and mercuric reductase (MerA) can sequentially demethylate methylmercury (MeHg) to Hg(II) and reduce Hg(II) to Hg0, respectively [ 67 ]. Fourteen MAGs contained mer gene encoding the mercuric ion pore superfamily, which catalyze Hg(II) uptake from the periplasm, and its transport across the membrane into the cytoplasm for reduction by MerA [ 68 ]. In addition, we found that 26 MAGs contained the merB gene.…”

Section: Resultsmentioning

confidence: 99%

Microbe-driven elemental cycling enables microbial adaptation to deep-sea ferromanganese nodule sediment fields

Zhang

et al. 2023

Microbiome

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Background Ferromanganese nodule-bearing deep-sea sediments cover vast areas of the ocean floor, representing a distinctive habitat in the abyss. These sediments harbor unique conditions characterized by high iron concentration and low degradable nutrient levels, which pose challenges to the survival and growth of most microorganisms. While the microbial diversity in ferromanganese nodule-associated sediments has been surveyed several times, little is known about the functional capacities of the communities adapted to these unique habitats. Results Seven sediment samples collected adjacent to ferromanganese nodules from the Clarion–Clipperton Fracture Zone (CCFZ) in the eastern Pacific Ocean were subjected to metagenomic analysis. As a result, 179 high-quality metagenome-assembled genomes (MAGs) were reconstructed and assigned to 21 bacterial phyla and 1 archaeal phylum, with 88.8% of the MAGs remaining unclassified at the species level. The main mechanisms of resistance to heavy metals for microorganisms in sediments included oxidation (Mn), reduction (Cr and Hg), efflux (Pb), synergy of reduction and efflux (As), and synergy of oxidation and efflux (Cu). Iron, which had the highest content among all metallic elements, may occur mainly as Fe(III) that potentially functioned as an electron acceptor. We found that microorganisms with a diverse array of CAZymes did not exhibit higher community abundance. Instead, microorganisms mainly obtained energy from oxidation of metal (e.g., Mn(II)) and sulfur compounds using oxygen or nitrate as an electron acceptor. Chemolithoautotrophic organisms (Thaumarchaeota and Nitrospirota phyla) were found to be potential manganese oxidizers. The functional profile analysis of the dominant microorganisms further indicated that utilization of inorganic nutrients by redox reactions (rather than organic nutrient metabolism) is a major adaptive strategy used by microorganisms to support their survival in the ferromanganese nodule sediments. Conclusions This study provides a comprehensive metagenomic analysis of microbes inhabiting metal-rich ferromanganese nodule sediments. Our results reveal extensive redundancy across taxa for pathways of metal resistance and transformation, the highly diverse mechanisms used by microbes to obtain nutrition, and their participation in various element cycles in these unique environments.

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Section: Resultsmentioning

confidence: 99%

Microbe-driven elemental cycling enables microbial adaptation to deep-sea ferromanganese nodule sediment fields

Zhang

et al. 2023

Microbiome

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“…1A), which together enable the bacterium to promptly respond to the mercury stress (Zheng et al ., 2018). Within the mer operon, the smallest of the mercury transporters, MerF has a molecular mass of only 8.7 kDa and consists solely of a simple helix‐loop‐helix domain with two pairs of cysteine residues for binding Hg 2+ (Hwang et al ., 2020), and it is the homologue of MerT, another reported Hg 2+ transporter (Sone et al ., 2013). However, combining our previous report (Zheng et al ., 2018) and the present study (Fig.…”

Section: Discussionmentioning

confidence: 99%

MerF is a novel regulator of deep‐sea Pseudomonas stutzeri flagellum biogenesis and motility

Zheng

Sun

2020

Environmental Microbiology

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Summary MerF, a proposed bacterial mercury transporter, was surprisingly found to play key roles in the flagellum biogenesis and motility but not mercuric resistance of the deep‐sea bacterium Pseudomonas stutzeri 273 in our previous study. However, the mechanism behind this interesting discovery has not been elucidated. Here, we firstly applied the combined transcriptomic and proteomic analysis to the P. stutzeri 273 wild type and merF deletion mutant. The results showed that expressions of extracellular flagellar components and FliS, a key factor controlling the biogenesis of extracellular flagellar filament, were significantly downregulated in the merF deletion mutant. In combination of genetic and biochemical methods, MerF was further demonstrated to regulate the expression of fliS via directly binding to its promoter, which is consistent with the discovery that MerF is essential for bacterial flagellum biogenesis and motility. Importantly, the expression of merF and fliS could be simultaneously upregulated by different heavy metals and MerF homologues exist in both bacterial and archaeal domains. To the best of our knowledge, this is the first report linking the heavy metal transporter and the flagellum biogenesis and motility in microorganisms, which provides a good model to investigate the unexplored adaptation strategies of deep‐sea microbes against harsh conditions.

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“…These genes provide plants with the ability to gather more Hg in their tissues than wild type. The merP encodes a periplasmic protein that facilitates the absorption of Hg 2+ and is physically linked to merT (Hwang et al, 2020).…”

Section: Phytoremediationmentioning

confidence: 99%

Bioremediation of mercury contaminated soil and water: A review

Kumar,

Chawla

et al. 2023

Land Degrad Dev

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Mercury (Hg) pollution of soil and water environments is a major global threat to human health, agri‐food systems and ecosystems and industrial activities mainly coal combustion augmented their content in different environmental media. Bioremediation is a nature‐based solution involving microbial‐ and plant‐based (phytoremediation) technologies that clean‐up Hg contaminated sites. Here, we review Hg‐resistant bacteria and how latest insights in our understanding of the cellular and biochemical mechanisms of the mer operon genes responsible for Hg resistance and transformation have facilitated developments in microbial Hg‐bioremediation. We also review the phytoremediation mechanisms, including those of bacterial‐ and fungi‐assisted phytoremediation processes, which have shown promising results in reducing Hg2+ to Hg0. This review provides a detailed knowledge of novel Hg bioremediation mechanisms and methods. Consequently, microbial‐ and phyto‐based bioremediation technologies have a critical role in the reclamation of Hg‐contaminated environments and the protection of human health and ecosystems.

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A Minimal Membrane Metal Transport System: Dynamics and Energetics of mer Proteins

Cited by 5 publications

References 50 publications

Microbe-driven elemental cycling enables microbial adaptation to deep-sea ferromanganese nodule sediment fields

Microbe-driven elemental cycling enables microbial adaptation to deep-sea ferromanganese nodule sediment fields

MerF is a novel regulator of deep‐sea Pseudomonas stutzeri flagellum biogenesis and motility

Bioremediation of mercury contaminated soil and water: A review

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