A Protonmotive Force Drives ATP Synthesis in Bacteria

Maloney, Peter C.; Kashket, Eva R.; Wilson, Thérèse

doi:10.1073/pnas.71.10.3896

Cited by 147 publications

(107 citation statements)

References 38 publications

(26 reference statements)

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“…and the function of this gene is also still unknown. E. hirae H+-ATPase can synthesize ATP when the proton motive force is imposed artificially (9,40,41,51). These data may suggest that the product of the i gene is not required for either enzyme assembly or enzyme function.…”

Section: Discussionmentioning

confidence: 68%

Gene structure of Enterococcus hirae (Streptococcus faecalis) F1F0-ATPase, which functions as a regulator of cytoplasmic pH

et al. 1992

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Enterococcus hirae (formerly Streptococcusfaecalis) ATCC 9790 has an F1F0-ATPase which functions as a regulator of the cytoplasmic pH but does not synthesize ATP. We isolated four clones which contained genes for c, b, delta, and alpha subunits of this enzyme but not for other subunit genes. It was revealed that two specific regions (upstream of the c-subunit gene and downstream of the gamma-subunit gene) were lost at a specific site in the clones we isolated, suggesting that these regions were unstable in Escherichia coli. The deleted regions were amplified by polymerase chain reaction, and the nucleotide sequences of these regions were determined. The results showed that eight genes for a, c, b, delta, alpha, gamma, beta, and epsilon subunits were present in this order. Northern (RNA) blot analysis showed that these eight genes were transcribed to one mRNA. The i gene was not found in the upper region of the a-subunit gene. Instead of the i gene, this operon contained a long untranslated region (240 bp) whose G+C content was only 30%1. There was no typical promoter sequence such as was proposed for E. coli, suggesting that the promoter structure of this species is different from that of E. coli. Deduced amino acid sequences suggested that E. hirae H+-ATPase is a typical F1F0-type ATPase but that its gene structure is not identical to that of other bacterial F1FO-ATPases.The anaerobic bacteria enterococci (streptococci) have a unique proton-translocating ATPase (H+-ATPase) which does not synthesize ATP but regulates the cytoplasmic pH in this species (16,17,29). The cytoplasmic pH is regulated by proton extrusion via the H+-ATPase and by potassium influx via the specific transport system for this ion. The latter system is not absolutely necessary for pH regulation, but dissipation of the membrane potential generated by the former system is definitely required. In fact, maintenance of neutral cytoplasmic pH can be attained in the presence of valinomycin, which dissipates the membrane potential (28).Biosynthesis of H+-ATPase is stimulated at a low cytoplasmic pH (2, 31). Data from our laboratory have shown that an elevated amount of H+-ATPase at a low pH is essential for maintaining neutral cytoplasmic pH (32, 49). Thus, it now appears that the primary factor for regulating cytoplasmic pH is the H+-ATPase in enterococci (streptococci). Abrams and his coworkers (1, 3-5, 36) have shown that Enterococcus hirae (formerly Streptococcus faecalis) H+-ATPase is biochemically similar to an F1FO-ATPase of aerobic bacteria which synthesizes ATP coupled with the proton motive force.In this study, we examined the gene structure of this H+-ATPase with E. hirae ATCC 9790. The operon for E. hirae H+-ATPase contained eight genes for a, c, b, delta, alpha, gamma, beta, and epsilon subunits in that order, and the deduced amino acid sequences of E. hirae H+-ATPase subunits had a high homology with those of other bacterial F1FO-ATPases. These with 5% trichloroacetic acid for 20 min in boiling water. Trichloroacetic acid was extrac...

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Section: Discussionmentioning

confidence: 68%

Gene structure of Enterococcus hirae (Streptococcus faecalis) F1F0-ATPase, which functions as a regulator of cytoplasmic pH

et al. 1992

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“…Since bacterial cells contain more than 200 mM of K' [9,14] and intracellular pH is about 7.5 [lO,lS] , the results presented above are well explained by that the transient motility was induced by an artificial protonmotive force, which was created either by the diffusion potential of K+ brought about by valinomycin (interior negative) or ApH due to pH drop (interior alkaline), or both. A low yield of the motile fraction by the pH drop alone may indicate that the ApH produced under the condition was not enough to support the translational swimming.…”

Section: Motility Induced By An Artificial Protonmotive Jbrcementioning

confidence: 61%

Motility in Bacillus subtilis driven by an artificial protonmotive force

1977

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“…Since the intracellular ATP concentration of enteric bacteria has been reported to be about 3 mM (4,26,29,58; for a review, see reference 37), we concluded that the concentration of acetyl-P is also about 3 mM. Implicit in this calculation is the assumption that all three of the phosphates within ATP are turned over at approximately the same rate.…”

Section: Discussionmentioning

confidence: 95%

The Intracellular Concentration of Acetyl Phosphate in Escherichia coli Is Sufficient for Direct Phosphorylation of Two-Component Response Regulators

et al. 2007

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Acetyl phosphate, the intermediate of the AckA-Pta pathway, acts as a global signal in Escherichia coli. Although acetyl phosphate clearly signals through two-component response regulators, it remains unclear whether acetyl phosphate acts as a direct phospho donor or functions through an indirect mechanism. We used two-dimensional thin-layer chromatography to measure the relative concentrations of acetyl phosphate, acetyl coenzyme A, ATP, and GTP over the course of the entire growth curve. We estimated that the intracellular concentration of acetyl phosphate in wild-type cells reaches at least 3 mM, a concentration sufficient to activate two-component response regulators via direct phosphoryl transfer.Bacterial cells must respond properly to diverse external and internal cues, a process that requires global signaling. The ideal global signal is metabolically inexpensive, short-lived, indicative only of significant changes, and capable of effecting the coordinated regulation of diverse cellular processes. Several lines of evidence suggest that the small molecule acetyl phosphate (acetyl-P) can serve as such a global signal.Acetyl-P is the high-energy, acid/base-labile intermediate of the reversible Pta-AckA pathway (Fig. 1). This pathway interconverts coenzyme A (HS-CoA), ATP, and acetate with acetyl coenzyme A (acetyl-CoA), ADP, and orthophosphate (P i ) (9, 43). The reversibility of this pathway permits both acetyl-CoA synthesis (acetate activation) and acetate evolution (acetogenesis). During acetogenesis, Pta synthesizes acetyl-P and HSCoA from acetyl-CoA and P i , while AckA generates ATP from acetyl-P and ADP. Simultaneously, AckA produces acetate, which cells excrete into the environment. Thus, the steadystate concentration of acetyl-P depends upon the rate of its formation catalyzed by Pta and the rate of its degradation catalyzed by AckA (for reviews, see references 45 and 59).Acetyl-P has been proposed to act as a global regulator by direct phosphorylation of response regulators (RRs) of the family of two-component signal transduction (2CST) pathways (34, 55). The simplest of these 2CST pathways consists of a histidine kinase (HK) and an RR. Using ATP as its phosphoryl donor, the HK autophosphorylates a conserved histidine residue. In turn, the RR autophosphorylates a conserved aspartate residue, using its phosphorylated cognate HK as its phosphoryl donor. Experiments performed in vitro have clearly demonstrated that acetyl-P can donate its phosphoryl group to purified RRs but not to HKs (for reviews, see references 52 and 57). This ability arises from its capacity to store energy. Acetyl-P possesses a larger ⌬G°of hydrolysis (Ϫ43.3 kJ/mol) than ATP possesses (Ϫ30.5 kJ/mol in complex with Mg 2ϩ ). This difference forms the basis for the role of acetyl-P in generating ATP (for a review, see reference 59).Although acetyl-P can function as a phosphoryl donor in vitro, its ability to function in vivo as a global signal has remained essentially unproven, despite a wealth of seemingly supportive data (for a r...

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A Protonmotive Force Drives ATP Synthesis in Bacteria

Cited by 147 publications

References 38 publications

Gene structure of Enterococcus hirae (Streptococcus faecalis) F1F0-ATPase, which functions as a regulator of cytoplasmic pH

Gene structure of Enterococcus hirae (Streptococcus faecalis) F1F0-ATPase, which functions as a regulator of cytoplasmic pH

Motility in Bacillus subtilis driven by an artificial protonmotive force

The Intracellular Concentration of Acetyl Phosphate in Escherichia coli Is Sufficient for Direct Phosphorylation of Two-Component Response Regulators

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