Identification of Na+-Pumping Cytochrome Oxidase in the Membranes of Extremely Alkaliphilic Thioalkalivibrio Bacteria

Muntyan, Maria S.; Morozov, Denis A.; Leonova, Yulia F.; Ovchinnikova, Tatiana V.

doi:10.1134/s0006297920120147

Cited by 1 publication

(3 citation statements)

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“…At the same time, in T. versutus, operation of the Na + -motive cytochrome-c oxidase enables the maintenance of a high negative electrical potential on their membranes [33], which is even higher than that shown in many alkaliphiles [35]. Direct methods have shown that the described sodium pump generates a high sodium-motive force (Δs [36]) across the bacterial cytoplasmic membranes [29], and has properties inherent in alkaliphilic proteins [37].…”

Section: Resultsmentioning

confidence: 99%

“…Being similar in architecture to the known cbb 3 oxidases, the Na + -motive oxidase has unique properties that open the way for favorable existence of natronophilic T. versutus in soda lakes [37]. Having specific motifs in the amino acid sequence of the catalytic subunit capable of binding Na + ions, this CO shows a strongly negative redox potential of the cytochrome-c-bearing subunits, which apparently promote energy conversion under alkaline conditions [37]. Based on our previous studies of T. versutus cells, we can deduce the ∆s value generated on their membranes in 5 min after substrate addition.…”

Section: Resultsmentioning

confidence: 99%

“…The membranes of the grown bacterial cells were isolated as described previously [63], with some modifications [37], and analyzed for heme content. For this purpose, heme was extracted from the isolated cellular membranes, and the following heme analysis was performed using HPLC as described previously [64], with some modifications [65].…”

Section: Analysis Of Hemesmentioning

confidence: 99%

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Sodium Energetic Cycle in the Natronophilic Bacterium Thioalkalivibrio versutus

Muntyan

Viryasov

Sorokin

et al. 2022

IJMS

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As inhabitants of soda lakes, Thioalkalivibrio versutus are halo- and alkaliphilic bacteria that have previously been shown to respire with the first demonstrated Na+-translocating cytochrome-c oxidase (CO). The enzyme generates a sodium-motive force (Δs) as high as −270 mV across the bacterial plasma membrane. However, in these bacteria, operation of the possible Δs consumers has not been proven. We obtained motile cells and used them to study the supposed Na+ energetic cycle in these bacteria. The resulting motility was activated in the presence of the protonophore 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), in line with the same effect on cell respiration, and was fully blocked by amiloride—an inhibitor of Na+-motive flagella. In immotile starving bacteria, ascorbate triggered CO-mediated respiration and motility, both showing the same dependence on sodium concentration. We concluded that, in T. versutus, Na+-translocating CO and Na+-motive flagella operate in the Na+ energetic cycle mode. Our research may shed light on the energetic reason for how these bacteria are confined to a narrow chemocline zone and thrive in the extreme conditions of soda lakes.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%