scholarly journals The cellular response towards lanthanum is substrate specific and reveals a novel route for glycerol metabolism inPseudomonas putidaKT2440

2019 ◽  
Author(s):  
Matthias Wehrmann ◽  
Maxime Toussaint ◽  
Jens Pfannstiel ◽  
Patrick Billard ◽  
Janosch Klebensberger
Keyword(s):  
Rare Earth ◽  
Cellular Response ◽  
Physiological Role ◽  
Physiological Traits ◽  
Glycerol Metabolism ◽  
Methylotrophic Bacteria ◽  
Environmental Implications ◽  
Glycerate Kinase ◽  
Proteomic Approach

AbstractEver since the discovery of the first rare earth element (REE)-dependent enzyme, the physiological role of lanthanides has become an emerging field of research due to the potential environmental implications and biotechnological opportunities. InPseudomonas putidaKT2440, the two pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) PedE and PedH are inversely produced in response to La3+-availability. This REE-switch is orchestrated by a complex regulatory network including the PedR2/PedS2 two-component system and is important for efficient growth on several alcoholic volatiles. AsP. putidais exposed to a broad variety of organic compounds in its natural soil habitat, the cellular responses towards La3+during growth on various carbon and energy sources were investigated with a differential proteomic approach. Apart from the Ca2+-dependent enzyme PedE, the differential abundance of most other identified proteins was conditional and revealed a substrate specificity. Concomitant with the proteomic changes, La3+had a beneficial effect on lag-phases while causing reduced growth rates and lower optical densities in stationary phase during growth on glycerol. When these growth phenotypes were evaluated with mutant strains, a novel metabolic route for glycerol utilization was identified that seems to be functional in parallel with the main degradation pathway encoded by theglpFKRDoperon. The newly discovered route is initiated by PedE and/or PedH, which most likely convert glycerol to glyceraldehyde. In the presence of lanthanum, glyceraldehyde seems to be further oxidized to glycerate, which, upon phosphorylation to glycerate-2-phosphate by the glycerate kinase GarK, is finally channelled into the central metabolism.ImportanceThe biological role of rare earth elements has long been underestimated and research has mainly focused on methanotrophic bacteria. We have recently demonstrated thatP. putida,a plant growth promoting bacterium that thrives in the rhizosphere of various feed crops, possesses a REE-dependent alcohol dehydrogenase (PedH), but knowledge about lanthanide-dependent effects on physiological traits in non-methylotrophic bacteria is still scarce. This study demonstrates that the cellular response ofP. putidaKT2440 towards La3+is mostly substrate specific and that during growth on glycerol, La3+has a severe effect on several growth parameters. We provide compelling evidence that the observed physiological changes are linked to the catalytic activity of PedH and thereby identify a novel route for glycerol metabolism in this biotechnological relevant organism. Overall, these findings demonstrate that lanthanides can alter important physiological traits of non-methylotrophic bacteria, which might consequently influence their competitiveness during colonization of various environmental niches.

scholarly journals The Cellular Response to Lanthanum Is Substrate Specific and Reveals a Novel Route for Glycerol Metabolism in Pseudomonas putida KT2440

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Matthias Wehrmann ◽  
Maxime Toussaint ◽  
Jens Pfannstiel ◽  
Patrick Billard ◽  
Janosch Klebensberger
Keyword(s):  
Pseudomonas Putida ◽  
Cellular Response ◽  
Physiological Role ◽  
Physiological Traits ◽  
Glycerol Metabolism ◽  
Methylotrophic Bacteria ◽  
Environmental Implications ◽  
Glycerate Kinase ◽  
Content Type

ABSTRACT Ever since the discovery of the first rare earth element (REE)-dependent enzyme, the physiological role of lanthanides has become an emerging field of research due to the environmental implications and biotechnological opportunities. In Pseudomonas putida KT2440, the two pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) PedE and PedH are inversely regulated in response to REE availability. This transcriptional switch is orchestrated by a complex regulatory network that includes the PedR2/PedS2 two-component system and is important for efficient growth on several alcoholic volatiles. To study whether cellular responses beyond the REE switch exist, the differential proteomic responses that occur during growth on various model carbon sources were analyzed. Apart from the Ca2+-dependent enzyme PedE, the differential abundances of most identified proteins were conditional. During growth on glycerol—and concomitant with the proteomic changes—lanthanum (La3+) availability affected different growth parameters, including the onset of logarithmic growth and final optical densities. Studies with mutant strains revealed a novel metabolic route for glycerol utilization, initiated by PedE and/or PedH activity. Upon oxidation to glycerate via glyceraldehyde, phosphorylation by the glycerate kinase GarK most likely yields glycerate-2-phosphate, which is eventually channeled into the central metabolism of the cell. This new route functions in parallel with the main degradation pathway encoded by the glpFKRD operon and provides a growth advantage to the cells by allowing an earlier onset of growth with glycerol as the sole source of carbon and energy. IMPORTANCE The biological role of REEs has long been underestimated, and research has mainly focused on methanotrophic and methylotrophic bacteria. We have recently demonstrated that P. putida, a plant growth-promoting bacterium that thrives in the rhizosphere of various food crops, possesses a REE-dependent alcohol dehydrogenase (PedH), but knowledge about REE-specific effects on physiological traits in nonmethylotrophic bacteria is still scarce. This study demonstrates that the cellular response of P. putida to lanthanum (La3+) is mostly substrate specific and that La3+ availability highly affects the growth of cells on glycerol. Further, a novel route for glycerol metabolism is identified, which is initiated by PedE and/or PedH activity and provides a growth advantage to this biotechnologically relevant organism by allowing a faster onset of growth. Overall, these findings demonstrate that lanthanides can affect physiological traits in nonmethylotrophic bacteria and might influence their competitiveness in various environmental niches.

scholarly journals Crystal structures of γ-glutamyltranspeptidase in complex with inhibitors

2014 ◽  
Vol 70 (a1) ◽  
pp. C847-C847
Author(s):  
Kei Hirabayashi ◽  
Tomoyo Ida ◽  
Chunjie Li ◽  
Hideyuki Suzuki ◽  
Keiichi Fukuyama ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Cellular Response ◽  
Physiological Role ◽  
Time Lapse ◽  
Binding Mode ◽  
E Coli ◽  
Glutathione Biosynthesis ◽  
Intracellular Glutathione ◽  
H Pylori

γ-Glutamyltranspeptidase (GGT; EC 2.3.2.2) is involved in the degradation of γ-glutamyl compounds such as glutathione (GSH; γ-glutamyl-cysteinyl-glycine) . A major physiological role of this enzyme is to cleave the extracellular GSH as a source of cysteine for intracellular glutathione biosynthesis. Another crucial role of GGT is to cleave glutathione-S-conjugates as a key step in detoxification of xenobiotics and drug metabolism. In mammals, GGT has been implicated in physiological disorders such as Parkinson's disease, other neurodegenerative diseases including Alzheimer's disease and cardiovascular disease. The indispensable roles played by GGT in GSH-mediated detoxification and cellular response to oxidative stress suggest that GGT is an attractive pharmaceutical target. We here report the binding mode of acivicin, a well-known glutamine antagonist, to B. subtilis GGT at 1.8 Å resolution showing that acivicin is bound to the Oγ atom of Thr403, the catalytic nucleophile of the enzyme, through its C3 atom [1]. The observed electron density around the C3 atom was best fitted to the planar and sp2 hybridized carbon, consistent with a simple nucleophilic substitution of Cl at the imino carbon by Oγ atom of Thr403. Furthermore, comparison of three bacterial enzymes, the GGTs from E. coli, H. pylori and B. subtilis in complex with acivicin, showed significant diversity in the orientation of the dihydroisoxazole ring among three GGTs. The differences are discussed in terms of the recognition of the α-amino and α-carboxy groups in preference to the dihydroisoxazole ring as observed in time-lapse soaking crystal structures of B. subtilis GGT with acivicin.

scholarly journals Genetic and biochemical characterization of the Na + /H + antiporters of Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Sara Foreman ◽  
Kristina Ferrara ◽  
Teri Hreha ◽  
Ana Duran-Pinedo ◽  
Jorge Frias-Lopez ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biochemical Characterization ◽  
Physiological Role ◽  
Glycerol Metabolism ◽  
Kinetic Properties ◽  
Wild Type ◽  
Wide Range ◽  
Quadruple Mutant

Pseudomonas aeruginosa has four Na + /H + antiporters that interconvert and balance Na + and H + gradients across the membrane. These gradients are important for bioenergetics and ionic homeostasis. To understand these transporters, we have constructed four strains, each of which has only one antiporter: NhaB, NhaP, NhaP2, and Mrp. We also constructed a quadruple deletion mutant that has no Na + /H + antiporters. Although the antiporters of P. aeruginosa have previously been studied, the strains constructed here present the opportunity to characterize their kinetic properties in their native membranes and their roles in the physiology of P. aeruginosa . The strains expressing only NhaB or Mrp, the two electrogenic antiporters, are able to grow essentially as the wild type across a range of [Na + ] and pH. Strains with only NhaP or NhaP2, which are electroneutral, grow more poorly at increasing [Na + ], especially at high pH, with NhaP the most sensitive. The strain with no Na + /H + antiporters is extremely sensitive to [Na + ] and shows essentially no Na + (Li + )/H + antiporter activity but retains most K + /H + antiporter activity of the wild type at pH 7.5 and approximately half at pH 8.5. We also used the four strains that each express one of the four antiporters to characterize the kinetic properties of each transporter. RNA-seq analysis of the quadruple deletion strain showed widespread changes, including pyocyanin synthesis, biofilm formation, and nitrate and glycerol metabolism. Thus, the strains constructed for this study will open a new door to understanding the physiological role of these proteins and their activities in P. aeruginosa . Importance Pseudomonas aeruginosa has four Na + /H + antiporters that connect and interconvert its Na + and H + gradients. We have constructed four deletion mutants, each of which has only one of the four Na + /H + antiporters. These strains made it possible to study the properties and physiological roles of each antiporter independently in its native membrane. Mrp and NhaB are each able to sustain growth over a wide range of pH and [Na + ], whereas the two electroneutral antiporters, NhaP and NhaP2, are most effective at low pH. We also constructed a quadruple mutant, lacking all four antiporters in which the H + and Na + gradients are disconnected. This will make it possible to study the role of the two gradients independently.

Physiological Role of Cyclic Electron Flow in Higher Plants

2012 ◽  
Vol 30 (1) ◽  
pp. 100
Author(s):  
Wei HUANG ◽  
Shi-Bao ZHANG ◽  
Kun-Fang CAO
Keyword(s):  
Higher Plants ◽  
Electron Flow ◽  
Physiological Role ◽  
Cyclic Electron Flow

The Renal Outer Medullary Potassium Channel (ROMK): An Intriguing Pharmacological Target for an Innovative Class of Diuretic Drugs

2018 ◽  
Vol 25 (23) ◽  
pp. 2627-2636 ◽  
Author(s):  
Vincenzo Calderone ◽  
Alma Martelli ◽  
Eugenia Piragine ◽  
Valentina Citi ◽  
Lara Testai ◽  
...  
Keyword(s):  
Physiological Role ◽  
Clinical Use ◽  
Diuretic Activity ◽  
First Line ◽  
Potassium Homeostasis ◽  
Diuretic Drugs ◽  
Pharmacological Target ◽  
Diuretic Agents ◽  
Effective Drugs

In the last four decades, the several classes of diuretics, currently available for clinical use, have been the first line option for the therapy of widespread cardiovascular and non-cardiovascular diseases. Diuretic drugs generally exhibit an overall favourable risk/benefit balance. However, they are not devoid of side effects. In particular, all the classes of diuretics cause alteration of potassium homeostasis. <p> In recent years, understanding of the physiological role of the renal outer medullary potassium (ROMK) channels, has shown an intriguing pharmacological target for developing an innovative class of diuretic agents: the ROMK inhibitors. This novel class is expected to promote diuretic activity comparable to (or even higher than) that provided by the most effective drugs used in clinics (such as furosemide), with limited effects on potassium homeostasis. <p> In this review, the physio-pharmacological roles of ROMK channels in the renal function are reported, along with the most representative molecules which have been currently developed as ROMK inhibitors.

THE PROVENANCE OF WINE: THE ROLE OF BEDROCK AND SOIL IN TRANSFERRING TRACE AND RARE EARTH ELEMENTS INTO WINE GRAPES, SONOMA COUNTY, CA

2019 ◽  
Author(s):  
Kylie E. Dupuis ◽  
◽  
Owen A. Anfinson ◽  
Laura Waters ◽  
Holli M. Frey ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Wine Grapes ◽  
Sonoma County
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