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P Dorenbos - One of the best experts on this subject based on the ideXlab platform.
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invited improved parameters for the Lanthanide 4fq and 4fq 15d curves in hrbe and vrbe schemes that takes the nephelauxetic effect into account
Journal of Luminescence, 2020Co-Authors: P DorenbosAbstract:Abstract In first approximation the binding of an electron in Lanthanide 4f q ground states changes with q in a characteristic zigzag shape that is independent on type of compound. Those shapes have been parameterized in past publications and are used to construct host referred binding energy (HRBE) or vacuum referred binding energy (VRBE) schemes showing the Lanthanide 4f q level locations with respect to the host valence bands or to the vacuum level. There is experimental evidence for a slight compound dependence, and a model explaining that has appeared recently (Dorenbos, 2019). This all implies that the parameters for constructing HRBE and VRBE schemes need to be revised and a compound dependence needs to be introduced as a second order approximation. In this work the improved parameters are derived from the 3 r d and 4 t h ionization potentials of the Lanthanide atoms. In compounds, as explained by the chemical shift model, the free ion binding energy curves undergo an upward shift due to Coulomb repulsion from anion ligands and they undergo a tilt due to the Lanthanide contraction. In this work we will use the nephelauxetic parameter β to add a compound dependence. Its main effect is an increased binding in the 4f q ground states for the Lanthanides from the right hand branch (q > 7) of the zigzag curves. The same applies for the 4f q − 1 5d excited states with ( q − 1 ) > 7 . Collected spectroscopic data on divalent and trivalent Lanthanides from more than 1000 different compounds have been analyzed to arrive at the proposed revised parameters for the 4f q and 4f q − 1 5d binding energy curves.
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the nephelauxetic effect on the electron binding energy in the 4fq ground state of Lanthanides in compounds
Journal of Luminescence, 2019Co-Authors: P DorenbosAbstract:Abstract In the construction of a vacuum referred binding energy (VRBE) diagram with the Lanthanide 4fq ground states, always a compound independent variation with the number q = 1 to 14 is assumed. Experimental data from thermo-luminescence, intervalence charge transfer bands, and thermo-bleaching studies provide first indications that a minor compound dependence does exist. To explain its origin we will first apply Jorgensen spin pairing theory to reproduce the VRBE in the ground states of the free di- and trivalent Lanthanide ions which is equivalent to the 3 r d and 4 t h ionization potentials of the Lanthanide atoms. By combining experimental data and calculated trends therein, the relevant Racah E 1 , Racah E 3 , and spin orbit coupling ζ ff parameters for all di-, tri-, and tetravalent free ion Lanthanides are derived. Using that as input for the spin pairing theory, the characteristic zigzag shapes in VRBE as function of q, as derived from ionization potentials, are nicely reproduced. Because of the nephelauxetic effect the parameter values are lowered when Lanthanides are in compounds. How that reduction affects the VRBE curves will be treated in this work.
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electronic structure engineering of Lanthanide activated materials
Journal of Materials Chemistry, 2012Co-Authors: P DorenbosAbstract:There are fourteen Lanthanides that may adopt the 2+ and 3+ charge states, and that can be incorporated into a countless number of compounds. Few tenths of an eV change in the location of the Lanthanide impurity states with respect to the host compound band states can have dramatic performance consequences. In this unimaginable large materials research field, knowledge on the electronic structure and how it changes with the type of Lanthanide and the type of compound are highly desired. Past years have witnessed large progress in our understanding, and today models to construct electronic structure diagrams have reached sufficient accuracy to provide a tool for engineering the properties of Lanthanide activated compounds. Here the models to construct those diagrams and how they can be utilized to explain or engineer properties are reviewed.
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Lanthanide charge transfer energies and related luminescence charge carrier trapping and redox phenomena
Journal of Alloys and Compounds, 2009Co-Authors: P DorenbosAbstract:The energy of electron transfer from the valence band to a trivalent Lanthanide ion provides information on the location of the ground state energy of the corresponding divalent Lanthanide ion relative to the top of the valence band. It turns out that the 14 divalent Lanthanides show a highly predictive pattern of the lowest 4f state energy location in compounds with the number n of electrons in the 4f shell. The lowest 4f state location controls important aspects like luminescence quantum efficiency, valence stability, and charge carrier trapping. An overview of our present state of knowledge is presented.
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spectroscopy and Lanthanide impurity level locations in caga2 s 4 ln3 ln ce pr tb er tm
Journal of The Electrochemical Society, 2004Co-Authors: Aurelie Bessiere, P Dorenbos, C W E Van Eijk, E Yamagishi, Chiharu Hidaka, Takeo TakizawaAbstract:The emission and excitation spectra of single crystals of CaGa 2 S 4 doped with Ce 3+ , Pr 3+ , Tb 3+ , Er 3+ , and Tm 3+ were measured with the aim to determine the location of the Lanthanide energy levels relative to the valence and conduction band of the host crystal. By combining energies known for charge transfer bands involving trivalent Lanthanides with systematic behavior in 4f-5d transition energies of divalent Lanthanides, the level positions of 4f and 5d states for each divalent Lanthanide can be drawn relative to the host levels. With similar techniques combined with results on the thermal quenching behavior of Ce 3+ emission, the levels for the trivalent Lanthanides were constructed. We demonstrate consistency between the proposed level scheme and the spectroscopic information presented here and elsewhere. The scintillation properties of Ce 3+ -doped CaGa 2 S 4 are addressed also.
Janosch Klebensberger - One of the best experts on this subject based on the ideXlab platform.
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functional role of Lanthanides in enzymatic activity and transcriptional regulation of pyrroloquinoline quinone dependent alcohol dehydrogenases in pseudomonas putida kt2440
Mbio, 2017Co-Authors: Matthias Wehrmann, Patrick Billard, Audrey Martinmeriadec, Asfaw Zegeye, Janosch KlebensbergerAbstract:The oxidation of alcohols and aldehydes is crucial for detoxification and efficient catabolism of various volatile organic compounds (VOCs). Thus, many Gram-negative bacteria have evolved periplasmic oxidation systems based on pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) that are often functionally redundant. Here we report the first description and characterization of a Lanthanide-dependent PQQ-ADH (PedH) in a nonmethylotrophic bacterium based on the use of purified enzymes from the soil-dwelling model organism Pseudomonas putida KT2440. PedH (PP_2679) exhibits enzyme activity on a range of substrates similar to that of its Ca2+-dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of Lanthanide ions, including La3+, Ce3+, Pr3+, Sm3+, or Nd3+ Reporter assays revealed that PedH not only has a catalytic function but is also involved in the transcriptional regulation of pedE and pedH, most likely acting as a sensory module. Notably, the underlying regulatory network is responsive to as little as 1 to 10 nM lanthanum, a concentration assumed to be of ecological relevance. The present study further demonstrates that the PQQ-dependent oxidation system is crucial for efficient growth with a variety of volatile alcohols. From these results, we conclude that functional redundancy and inverse regulation of PedE and PedH represent an adaptive strategy of P. putida KT2440 to optimize growth with volatile alcohols in response to the availability of different Lanthanides.IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments.
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functional role of Lanthanides in enzymatic activity and transcriptional regulation of pyrroloquinoline quinone dependent alcohol dehydrogenases in pseudomonas putida kt2440
Mbio, 2017Co-Authors: Matthias Wehrmann, Patrick Billard, Audrey Martinmeriadec, Asfaw Zegeye, Janosch KlebensbergerAbstract:ABSTRACT The oxidation of alcohols and aldehydes is crucial for detoxification and efficient catabolism of various volatile organic compounds (VOCs). Thus, many Gram-negative bacteria have evolved periplasmic oxidation systems based on pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) that are often functionally redundant. Here we report the first description and characterization of a Lanthanide-dependent PQQ-ADH (PedH) in a nonmethylotrophic bacterium based on the use of purified enzymes from the soil-dwelling model organism Pseudomonas putida KT2440. PedH (PP_2679) exhibits enzyme activity on a range of substrates similar to that of its Ca 2+ -dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of Lanthanide ions, including La 3+ , Ce 3+ , Pr 3+ , Sm 3+ , or Nd 3+ . Reporter assays revealed that PedH not only has a catalytic function but is also involved in the transcriptional regulation of pedE and pedH , most likely acting as a sensory module. Notably, the underlying regulatory network is responsive to as little as 1 to 10 nM lanthanum, a concentration assumed to be of ecological relevance. The present study further demonstrates that the PQQ-dependent oxidation system is crucial for efficient growth with a variety of volatile alcohols. From these results, we conclude that functional redundancy and inverse regulation of PedE and PedH represent an adaptive strategy of P. putida KT2440 to optimize growth with volatile alcohols in response to the availability of different Lanthanides. IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments. IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments.
Patrick Billard - One of the best experts on this subject based on the ideXlab platform.
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functional role of Lanthanides in enzymatic activity and transcriptional regulation of pyrroloquinoline quinone dependent alcohol dehydrogenases in pseudomonas putida kt2440
Mbio, 2017Co-Authors: Matthias Wehrmann, Patrick Billard, Audrey Martinmeriadec, Asfaw Zegeye, Janosch KlebensbergerAbstract:The oxidation of alcohols and aldehydes is crucial for detoxification and efficient catabolism of various volatile organic compounds (VOCs). Thus, many Gram-negative bacteria have evolved periplasmic oxidation systems based on pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) that are often functionally redundant. Here we report the first description and characterization of a Lanthanide-dependent PQQ-ADH (PedH) in a nonmethylotrophic bacterium based on the use of purified enzymes from the soil-dwelling model organism Pseudomonas putida KT2440. PedH (PP_2679) exhibits enzyme activity on a range of substrates similar to that of its Ca2+-dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of Lanthanide ions, including La3+, Ce3+, Pr3+, Sm3+, or Nd3+ Reporter assays revealed that PedH not only has a catalytic function but is also involved in the transcriptional regulation of pedE and pedH, most likely acting as a sensory module. Notably, the underlying regulatory network is responsive to as little as 1 to 10 nM lanthanum, a concentration assumed to be of ecological relevance. The present study further demonstrates that the PQQ-dependent oxidation system is crucial for efficient growth with a variety of volatile alcohols. From these results, we conclude that functional redundancy and inverse regulation of PedE and PedH represent an adaptive strategy of P. putida KT2440 to optimize growth with volatile alcohols in response to the availability of different Lanthanides.IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments.
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functional role of Lanthanides in enzymatic activity and transcriptional regulation of pyrroloquinoline quinone dependent alcohol dehydrogenases in pseudomonas putida kt2440
Mbio, 2017Co-Authors: Matthias Wehrmann, Patrick Billard, Audrey Martinmeriadec, Asfaw Zegeye, Janosch KlebensbergerAbstract:ABSTRACT The oxidation of alcohols and aldehydes is crucial for detoxification and efficient catabolism of various volatile organic compounds (VOCs). Thus, many Gram-negative bacteria have evolved periplasmic oxidation systems based on pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) that are often functionally redundant. Here we report the first description and characterization of a Lanthanide-dependent PQQ-ADH (PedH) in a nonmethylotrophic bacterium based on the use of purified enzymes from the soil-dwelling model organism Pseudomonas putida KT2440. PedH (PP_2679) exhibits enzyme activity on a range of substrates similar to that of its Ca 2+ -dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of Lanthanide ions, including La 3+ , Ce 3+ , Pr 3+ , Sm 3+ , or Nd 3+ . Reporter assays revealed that PedH not only has a catalytic function but is also involved in the transcriptional regulation of pedE and pedH , most likely acting as a sensory module. Notably, the underlying regulatory network is responsive to as little as 1 to 10 nM lanthanum, a concentration assumed to be of ecological relevance. The present study further demonstrates that the PQQ-dependent oxidation system is crucial for efficient growth with a variety of volatile alcohols. From these results, we conclude that functional redundancy and inverse regulation of PedE and PedH represent an adaptive strategy of P. putida KT2440 to optimize growth with volatile alcohols in response to the availability of different Lanthanides. IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments. IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments.
Asfaw Zegeye - One of the best experts on this subject based on the ideXlab platform.
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functional role of Lanthanides in enzymatic activity and transcriptional regulation of pyrroloquinoline quinone dependent alcohol dehydrogenases in pseudomonas putida kt2440
Mbio, 2017Co-Authors: Matthias Wehrmann, Patrick Billard, Audrey Martinmeriadec, Asfaw Zegeye, Janosch KlebensbergerAbstract:The oxidation of alcohols and aldehydes is crucial for detoxification and efficient catabolism of various volatile organic compounds (VOCs). Thus, many Gram-negative bacteria have evolved periplasmic oxidation systems based on pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) that are often functionally redundant. Here we report the first description and characterization of a Lanthanide-dependent PQQ-ADH (PedH) in a nonmethylotrophic bacterium based on the use of purified enzymes from the soil-dwelling model organism Pseudomonas putida KT2440. PedH (PP_2679) exhibits enzyme activity on a range of substrates similar to that of its Ca2+-dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of Lanthanide ions, including La3+, Ce3+, Pr3+, Sm3+, or Nd3+ Reporter assays revealed that PedH not only has a catalytic function but is also involved in the transcriptional regulation of pedE and pedH, most likely acting as a sensory module. Notably, the underlying regulatory network is responsive to as little as 1 to 10 nM lanthanum, a concentration assumed to be of ecological relevance. The present study further demonstrates that the PQQ-dependent oxidation system is crucial for efficient growth with a variety of volatile alcohols. From these results, we conclude that functional redundancy and inverse regulation of PedE and PedH represent an adaptive strategy of P. putida KT2440 to optimize growth with volatile alcohols in response to the availability of different Lanthanides.IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments.
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functional role of Lanthanides in enzymatic activity and transcriptional regulation of pyrroloquinoline quinone dependent alcohol dehydrogenases in pseudomonas putida kt2440
Mbio, 2017Co-Authors: Matthias Wehrmann, Patrick Billard, Audrey Martinmeriadec, Asfaw Zegeye, Janosch KlebensbergerAbstract:ABSTRACT The oxidation of alcohols and aldehydes is crucial for detoxification and efficient catabolism of various volatile organic compounds (VOCs). Thus, many Gram-negative bacteria have evolved periplasmic oxidation systems based on pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) that are often functionally redundant. Here we report the first description and characterization of a Lanthanide-dependent PQQ-ADH (PedH) in a nonmethylotrophic bacterium based on the use of purified enzymes from the soil-dwelling model organism Pseudomonas putida KT2440. PedH (PP_2679) exhibits enzyme activity on a range of substrates similar to that of its Ca 2+ -dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of Lanthanide ions, including La 3+ , Ce 3+ , Pr 3+ , Sm 3+ , or Nd 3+ . Reporter assays revealed that PedH not only has a catalytic function but is also involved in the transcriptional regulation of pedE and pedH , most likely acting as a sensory module. Notably, the underlying regulatory network is responsive to as little as 1 to 10 nM lanthanum, a concentration assumed to be of ecological relevance. The present study further demonstrates that the PQQ-dependent oxidation system is crucial for efficient growth with a variety of volatile alcohols. From these results, we conclude that functional redundancy and inverse regulation of PedE and PedH represent an adaptive strategy of P. putida KT2440 to optimize growth with volatile alcohols in response to the availability of different Lanthanides. IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments. IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments.
Audrey Martinmeriadec - One of the best experts on this subject based on the ideXlab platform.
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functional role of Lanthanides in enzymatic activity and transcriptional regulation of pyrroloquinoline quinone dependent alcohol dehydrogenases in pseudomonas putida kt2440
Mbio, 2017Co-Authors: Matthias Wehrmann, Patrick Billard, Audrey Martinmeriadec, Asfaw Zegeye, Janosch KlebensbergerAbstract:The oxidation of alcohols and aldehydes is crucial for detoxification and efficient catabolism of various volatile organic compounds (VOCs). Thus, many Gram-negative bacteria have evolved periplasmic oxidation systems based on pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) that are often functionally redundant. Here we report the first description and characterization of a Lanthanide-dependent PQQ-ADH (PedH) in a nonmethylotrophic bacterium based on the use of purified enzymes from the soil-dwelling model organism Pseudomonas putida KT2440. PedH (PP_2679) exhibits enzyme activity on a range of substrates similar to that of its Ca2+-dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of Lanthanide ions, including La3+, Ce3+, Pr3+, Sm3+, or Nd3+ Reporter assays revealed that PedH not only has a catalytic function but is also involved in the transcriptional regulation of pedE and pedH, most likely acting as a sensory module. Notably, the underlying regulatory network is responsive to as little as 1 to 10 nM lanthanum, a concentration assumed to be of ecological relevance. The present study further demonstrates that the PQQ-dependent oxidation system is crucial for efficient growth with a variety of volatile alcohols. From these results, we conclude that functional redundancy and inverse regulation of PedE and PedH represent an adaptive strategy of P. putida KT2440 to optimize growth with volatile alcohols in response to the availability of different Lanthanides.IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments.
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functional role of Lanthanides in enzymatic activity and transcriptional regulation of pyrroloquinoline quinone dependent alcohol dehydrogenases in pseudomonas putida kt2440
Mbio, 2017Co-Authors: Matthias Wehrmann, Patrick Billard, Audrey Martinmeriadec, Asfaw Zegeye, Janosch KlebensbergerAbstract:ABSTRACT The oxidation of alcohols and aldehydes is crucial for detoxification and efficient catabolism of various volatile organic compounds (VOCs). Thus, many Gram-negative bacteria have evolved periplasmic oxidation systems based on pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ-ADHs) that are often functionally redundant. Here we report the first description and characterization of a Lanthanide-dependent PQQ-ADH (PedH) in a nonmethylotrophic bacterium based on the use of purified enzymes from the soil-dwelling model organism Pseudomonas putida KT2440. PedH (PP_2679) exhibits enzyme activity on a range of substrates similar to that of its Ca 2+ -dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of Lanthanide ions, including La 3+ , Ce 3+ , Pr 3+ , Sm 3+ , or Nd 3+ . Reporter assays revealed that PedH not only has a catalytic function but is also involved in the transcriptional regulation of pedE and pedH , most likely acting as a sensory module. Notably, the underlying regulatory network is responsive to as little as 1 to 10 nM lanthanum, a concentration assumed to be of ecological relevance. The present study further demonstrates that the PQQ-dependent oxidation system is crucial for efficient growth with a variety of volatile alcohols. From these results, we conclude that functional redundancy and inverse regulation of PedE and PedH represent an adaptive strategy of P. putida KT2440 to optimize growth with volatile alcohols in response to the availability of different Lanthanides. IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments. IMPORTANCE Because of their low bioavailability, Lanthanides have long been considered biologically inert. In recent years, however, the identification of Lanthanides as a cofactor in methylotrophic bacteria has attracted tremendous interest among various biological fields. The present study reveals that one of the two PQQ-ADHs produced by the model organism P. putida KT2440 also utilizes Lanthanides as a cofactor, thus expanding the scope of Lanthanide-employing bacteria beyond the methylotrophs. Similar to the system described in methylotrophic bacteria, a complex regulatory network is involved in Lanthanide-responsive switching between the two PQQ-ADHs encoded by P. putida KT2440. We further show that the functional production of at least one of the enzymes is crucial for efficient growth with several volatile alcohols. Overall, our study provides a novel understanding of the redundancy of PQQ-ADHs observed in many organisms and further highlights the importance of Lanthanides for bacterial metabolism, particularly in soil environments.
