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  1. Article ; Online: Characterisation of kinetics, substrate inhibition and product activation by AMP of bifunctional ADP-dependent glucokinase/phosphofructokinase from Methanococcus maripaludis.

    Vallejos-Baccelliere, Gabriel / Kaufman, Sergio B / González-Lebrero, Rodolfo M / Castro-Fernandez, Víctor / Guixé, Victoria

    The FEBS journal

    2022  Volume 289, Issue 23, Page(s) 7519–7536

    Abstract: Methanogenic archaea have received attention due to their potential use in biotechnological applications such as methane production, so their metabolism and regulation are topics of special interest. When growing in a nutrient-rich medium, these ... ...

    Abstract Methanogenic archaea have received attention due to their potential use in biotechnological applications such as methane production, so their metabolism and regulation are topics of special interest. When growing in a nutrient-rich medium, these organisms exhibit gluconeogenic metabolism; however, under starvation conditions, they turn to glycolytic metabolism. To date, no regulatory mechanism has been described for this gluconeogenic/glycolytic metabolic switch. Here, we report that adenosine monophosphate (AMP) activates both enzymatic activities of the bifunctional adenosine diphosphate (ADP)-dependent phosphofructokinase/glucokinase from Methanococcus maripaludis (MmPFK/GK). To understand this phenomenon, we performed a comprehensive kinetic characterisation, including determination of the kinetics, substrate inhibition and AMP activation mechanism of this enzyme. We determined that MmPFK/GK has an ordered-sequential mechanism, in which MgADP is the first substrate to bind and AMP is the last product released. The enzyme also displays substrate inhibition by both sugar substrates; we determined that this inhibition occurs through the formation of catalytically nonproductive enzyme complexes caused by sugar binding. For both activities, the AMP activation mechanism occurs primarily through incremental changes in the affinity for the sugar substrate, with this effect being higher in the GK than in the PFK activity. Interestingly, due to the increase in the sugar substrate affinity caused by AMP, an enhancement in the sugar substrate inhibition effect was also observed for both activities, which can be explained by an increase in sugar binding leading to the formation of dead-end complexes. These results shed light on the regulatory mechanisms of methanogenic archaeal sugar metabolism, a phenomenon that has been largely unexplored.
    MeSH term(s) Phosphofructokinases ; Adenosine Diphosphate ; Adenosine Monophosphate ; Methanococcus/genetics ; Sugars
    Chemical Substances Phosphofructokinases (EC 2.7.1 -) ; Adenosine Diphosphate (61D2G4IYVH) ; Adenosine Monophosphate (415SHH325A) ; ADP-dependent glucokinase (EC 2.7.1.-) ; Sugars
    Language English
    Publishing date 2022-06-29
    Publishing country England
    Document type Journal Article
    ZDB-ID 2173655-8
    ISSN 1742-4658 ; 1742-464X
    ISSN (online) 1742-4658
    ISSN 1742-464X
    DOI 10.1111/febs.16557
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  2. Article ; Online: Characterisation of kinetics, substrate inhibition and product activation by AMP of bifunctional ADP‐dependent glucokinase/phosphofructokinase from Methanococcus maripaludis

    Vallejos‐Baccelliere, Gabriel / Kaufman, Sergio B. / González‐Lebrero, Rodolfo M. / Castro‐Fernandez, Víctor / Guixé, Victoria

    The FEBS Journal. 2022 Dec., v. 289, no. 23 p.7519-7536

    2022  

    Abstract: Methanogenic archaea have received attention due to their potential use in biotechnological applications such as methane production, so their metabolism and regulation are topics of special interest. When growing in a nutrient‐rich medium, these ... ...

    Abstract Methanogenic archaea have received attention due to their potential use in biotechnological applications such as methane production, so their metabolism and regulation are topics of special interest. When growing in a nutrient‐rich medium, these organisms exhibit gluconeogenic metabolism; however, under starvation conditions, they turn to glycolytic metabolism. To date, no regulatory mechanism has been described for this gluconeogenic/glycolytic metabolic switch. Here, we report that adenosine monophosphate (AMP) activates both enzymatic activities of the bifunctional adenosine diphosphate (ADP)‐dependent phosphofructokinase/glucokinase from Methanococcus maripaludis (MmPFK/GK). To understand this phenomenon, we performed a comprehensive kinetic characterisation, including determination of the kinetics, substrate inhibition and AMP activation mechanism of this enzyme. We determined that MmPFK/GK has an ordered‐sequential mechanism, in which MgADP is the first substrate to bind and AMP is the last product released. The enzyme also displays substrate inhibition by both sugar substrates; we determined that this inhibition occurs through the formation of catalytically nonproductive enzyme complexes caused by sugar binding. For both activities, the AMP activation mechanism occurs primarily through incremental changes in the affinity for the sugar substrate, with this effect being higher in the GK than in the PFK activity. Interestingly, due to the increase in the sugar substrate affinity caused by AMP, an enhancement in the sugar substrate inhibition effect was also observed for both activities, which can be explained by an increase in sugar binding leading to the formation of dead‐end complexes. These results shed light on the regulatory mechanisms of methanogenic archaeal sugar metabolism, a phenomenon that has been largely unexplored.
    Keywords Methanococcus maripaludis ; adenosine diphosphate ; adenosine monophosphate ; glucokinase ; glycolysis ; methane production ; methanogens ; phosphofructokinases ; starvation ; sugars
    Language English
    Dates of publication 2022-12
    Size p. 7519-7536.
    Publishing place John Wiley & Sons, Ltd
    Document type Article ; Online
    Note JOURNAL ARTICLE
    ZDB-ID 2173655-8
    ISSN 1742-4658 ; 1742-464X
    ISSN (online) 1742-4658
    ISSN 1742-464X
    DOI 10.1111/febs.16557
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  3. Article ; Online: Functional characterization of Legionella pneumophila Cu

    Placenti, M Agueda / Roman, Ernesto A / González Flecha, F Luis / González-Lebrero, Rodolfo M

    Biochimica et biophysica acta. Biomembranes

    2021  Volume 1864, Issue 2, Page(s) 183822

    Abstract: ... ...

    Abstract Cu
    MeSH term(s) Adenosine Triphosphatases/metabolism ; Adenosine Triphosphate/metabolism ; Cation Transport Proteins/metabolism ; Copper/metabolism ; Ion Transport ; Kinetics ; Legionella pneumophila/enzymology ; Models, Molecular ; Protein Binding
    Chemical Substances Cation Transport Proteins ; Copper (789U1901C5) ; Adenosine Triphosphate (8L70Q75FXE) ; Adenosine Triphosphatases (EC 3.6.1.-)
    Language English
    Publishing date 2021-11-24
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 60-7
    ISSN 1879-2642 ; 1879-2596 ; 1879-260X ; 1872-8006 ; 1879-2618 ; 1879-2650 ; 0006-3002 ; 0005-2728 ; 0005-2736 ; 0304-4165 ; 0167-4838 ; 1388-1981 ; 0167-4889 ; 0167-4781 ; 0304-419X ; 1570-9639 ; 0925-4439 ; 1874-9399
    ISSN (online) 1879-2642 ; 1879-2596 ; 1879-260X ; 1872-8006 ; 1879-2618 ; 1879-2650
    ISSN 0006-3002 ; 0005-2728 ; 0005-2736 ; 0304-4165 ; 0167-4838 ; 1388-1981 ; 0167-4889 ; 0167-4781 ; 0304-419X ; 1570-9639 ; 0925-4439 ; 1874-9399
    DOI 10.1016/j.bbamem.2021.183822
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  4. Article ; Online: A laboratory work to introduce biochemistry undergraduate students to basic enzyme kinetics-alkaline phosphatase as a model.

    Miquet, Johanna G / González, Lorena / Sotelo, Ana I / González Lebrero, Rodolfo M

    Biochemistry and molecular biology education : a bimonthly publication of the International Union of Biochemistry and Molecular Biology

    2018  Volume 47, Issue 1, Page(s) 93–99

    Abstract: Enzyme kinetics is an essential topic in undergraduate Biochemistry courses. A laboratory work that covers the principal basic concepts of enzyme kinetics in steady state is presented. The alkaline phosphatase catalyzed reaction of phenyl-phosphate ... ...

    Abstract Enzyme kinetics is an essential topic in undergraduate Biochemistry courses. A laboratory work that covers the principal basic concepts of enzyme kinetics in steady state is presented. The alkaline phosphatase catalyzed reaction of phenyl-phosphate hydrolysis was studied as a model. The laboratory experience was designed to reinforce the concepts of initial velocity dependence on substrate and enzyme concentration, and to highlight the importance of the accurate determination of initial reaction rate. The laboratory work consists in two parts, in which students first determine the enzyme concentration and the time to be used in the following session to obtain the kinetic parameters (K
    MeSH term(s) Alkaline Phosphatase/metabolism ; Biochemistry ; Humans ; Kinetics ; Laboratories ; Models, Biological ; Students ; Universities
    Chemical Substances Alkaline Phosphatase (EC 3.1.3.1)
    Language English
    Publishing date 2018-12-21
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1539-3429
    ISSN (online) 1539-3429
    DOI 10.1002/bmb.21195
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  5. Article ; Online: Thermodynamic study of the effect of ions on the interaction between dengue virus NS3 helicase and single stranded RNA.

    Cababie, Leila A / Incicco, J Jeremías / González-Lebrero, Rodolfo M / Roman, Ernesto A / Gebhard, Leopoldo G / Gamarnik, Andrea V / Kaufman, Sergio B

    Scientific reports

    2019  Volume 9, Issue 1, Page(s) 10569

    Abstract: Dengue virus nonstructural protein 3 (NS3) fulfills multiple essential functions during the viral replication and constitutes a prominent drug target. NS3 is composed by a superfamily-2 RNA helicase domain joined to a serine protease domain. Quantitative ...

    Abstract Dengue virus nonstructural protein 3 (NS3) fulfills multiple essential functions during the viral replication and constitutes a prominent drug target. NS3 is composed by a superfamily-2 RNA helicase domain joined to a serine protease domain. Quantitative fluorescence titrations employing a fluorescein-tagged RNA oligonucleotide were used to investigate the effect of salts on the interaction between NS3 and single stranded RNA (ssRNA). We found a strong dependence of the observed equilibrium binding constant, K
    MeSH term(s) Dengue Virus/enzymology ; Dengue Virus/genetics ; Dengue Virus/metabolism ; Fluorescence ; RNA Helicases/metabolism ; RNA, Viral/metabolism ; Serine Endopeptidases/metabolism ; Thermodynamics ; Viral Nonstructural Proteins/metabolism ; Viral Proteins/metabolism
    Chemical Substances NS3 protein, flavivirus ; RNA, Viral ; Viral Nonstructural Proteins ; Viral Proteins ; Serine Endopeptidases (EC 3.4.21.-) ; RNA Helicases (EC 3.6.4.13)
    Language English
    Publishing date 2019-07-22
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-019-46741-4
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  6. Article ; Online: Folding and Dynamics Are Strongly pH-Dependent in a Psychrophile Frataxin.

    González-Lebrero, Rodolfo M / Defelipe, Lucas / Modenutti, Carlos / Roitberg, Adrian E / Batastini, Nicolas A / Noguera, Martín E / Santos, Javier / Roman, Ernesto A

    The journal of physical chemistry. B

    2019  Volume 123, Issue 36, Page(s) 7676–7686

    Abstract: Protein dynamics, folding, and thermodynamics represent a central aspect of biophysical chemistry. pH, temperature, and denaturant perturbations inform our understanding of diverse contributors to stability and rates. In this work, we performed a ... ...

    Abstract Protein dynamics, folding, and thermodynamics represent a central aspect of biophysical chemistry. pH, temperature, and denaturant perturbations inform our understanding of diverse contributors to stability and rates. In this work, we performed a thermodynamic analysis using a combined experimental and computational approach to gain insights into the role of electrostatics in the folding reaction of a psychrophile frataxin variant from
    MeSH term(s) Hydrogen-Ion Concentration ; Iron-Binding Proteins/chemistry ; Molecular Dynamics Simulation ; Protein Folding ; Thermodynamics ; Frataxin
    Chemical Substances Iron-Binding Proteins
    Language English
    Publishing date 2019-08-27
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.9b05960
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  7. Article ; Online: Unexpected Effects of K

    Placenti, M Agueda / Kaufman, Sergio B / González Flecha, F Luis / González Lebrero, Rodolfo M

    The journal of physical chemistry. B

    2017  Volume 121, Issue 19, Page(s) 4949–4957

    Abstract: ... ...

    Abstract Na
    Language English
    Publishing date 2017-05-18
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.7b00629
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  8. Article: Folding and Dynamics Are Strongly pH-Dependent in a Psychrophile Frataxin

    González-Lebrero, Rodolfo M / Defelipe, Lucas / Modenutti, Carlos / Roitberg, Adrian E / Batastini, Nicolas A / Noguera, Martín E / Santos, Javier / Roman, Ernesto A

    Journal of physical chemistry. 2019 Aug. 13, v. 123, no. 36

    2019  

    Abstract: Protein dynamics, folding, and thermodynamics represent a central aspect of biophysical chemistry. pH, temperature, and denaturant perturbations inform our understanding of diverse contributors to stability and rates. In this work, we performed a ... ...

    Abstract Protein dynamics, folding, and thermodynamics represent a central aspect of biophysical chemistry. pH, temperature, and denaturant perturbations inform our understanding of diverse contributors to stability and rates. In this work, we performed a thermodynamic analysis using a combined experimental and computational approach to gain insights into the role of electrostatics in the folding reaction of a psychrophile frataxin variant from Psychromonas ingrahamii. This folding reaction is strongly modulated by pH with a single, narrow, and well-defined transition state with ∼80% compactness, ∼70% electrostatic interactions, and ∼60% hydration shell compared to the native state (αD = 0.82, αH = 0.67, and αΔCₚ = 0.59). Our results are best explained by a two-proton/two-state model with very different pKₐ values of the native and denatured states (∼5.5 and ∼8.0, respectively). As a consequence, the stability strongly increases from pH 8.0 to 6.0 (|ΔΔG°| = 5.2 kcal mol–¹), mainly because of a decrease in the TΔS°. Variation of ΔH° and ΔS° at pH below 7.0 is dominated by a change in ΔHf⧧ and ΔSf⧧, while at pH above 7.0, it is governed by ΔHᵤ⧧ and ΔSᵤ⧧. Molecular dynamics simulations showed that these pH modulations could be explained by the fluctuations of two regions, rich in electrostatic contacts, whose dynamics are pH-dependent and motions are strongly correlated. Results presented herein contribute to the understanding of the stability and dynamics of this frataxin variant, pointing to an intrinsic feature of the family topology to support different folding mechanisms.
    Keywords Psychromonas ; electrostatic interactions ; molecular dynamics ; pH ; simulation models ; temperature ; thermodynamics ; topology
    Language English
    Dates of publication 2019-0813
    Size p. 7676-7686.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1520-5207
    DOI 10.1021/acs.jpcb.9b05960
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  9. Article ; Online: Human Frataxin Folds Via an Intermediate State. Role of the C-Terminal Region.

    Faraj, Santiago E / González-Lebrero, Rodolfo M / Roman, Ernesto A / Santos, Javier

    Scientific reports

    2016  Volume 6, Page(s) 20782

    Abstract: The aim of this study is to investigate the folding reaction of human frataxin, whose deficiency causes the neurodegenerative disease Friedreich's Ataxia (FRDA). The characterization of different conformational states would provide knowledge about how ... ...

    Abstract The aim of this study is to investigate the folding reaction of human frataxin, whose deficiency causes the neurodegenerative disease Friedreich's Ataxia (FRDA). The characterization of different conformational states would provide knowledge about how frataxin can be stabilized without altering its functionality. Wild-type human frataxin and a set of mutants, including two highly destabilized FRDA-associated variants were studied by urea-induced folding/unfolding in a rapid mixing device and followed by circular dichroism. The analysis clearly indicates the existence of an intermediate state (I) in the folding route with significant secondary structure content but relatively low compactness, compared with the native ensemble. However, at high NaCl concentrations I-state gains substantial compaction, and the unfolding barrier is strongly affected, revealing the importance of electrostatics in the folding mechanism. The role of the C-terminal region (CTR), the key determinant of frataxin stability, was also studied. Simulations consistently with experiments revealed that this stretch is essentially unstructured, in the most compact transition state ensemble (TSE2). The complete truncation of the CTR drastically destabilizes the native state without altering TSE2. Results presented here shed light on the folding mechanism of frataxin, opening the possibility of mutating it to generate hyperstable variants without altering their folding kinetics.
    MeSH term(s) Circular Dichroism ; Friedreich Ataxia/metabolism ; Humans ; Iron-Binding Proteins/chemistry ; Iron-Binding Proteins/metabolism ; Protein Domains ; Protein Stability ; Protein Structure, Secondary ; Protein Unfolding ; Recombinant Proteins ; Sodium Chloride/chemistry ; Urea/chemistry ; Frataxin
    Chemical Substances Iron-Binding Proteins ; Recombinant Proteins ; Sodium Chloride (451W47IQ8X) ; Urea (8W8T17847W)
    Language English
    Publishing date 2016-02-09
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/srep20782
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  10. Article ; Online: Opposing effects of Na+ and K+ on the thermal stability of Na+,K(+)-ATPase.

    Kaufman, Sergio B / González-Flecha, F Luis / González-Lebrero, Rodolfo M

    The journal of physical chemistry. B

    2012  Volume 116, Issue 10, Page(s) 3421–3429

    Abstract: Folding and structural stability are key factors for the proper biological function of proteins. Na(+),K(+)-ATPase is an integral membrane protein involved in the active transport of Na(+) and K(+) across the plasma membrane. In this work we ... ...

    Abstract Folding and structural stability are key factors for the proper biological function of proteins. Na(+),K(+)-ATPase is an integral membrane protein involved in the active transport of Na(+) and K(+) across the plasma membrane. In this work we characterized the effects of K(+) and Na(+) on the thermal inactivation of Na(+),K(+)-ATPase, evaluating both catalytic and transport capacities of the pump. Both activities of the enzyme decrease with the preincubation time as first-order kinetics. The thermal inactivation of Na(+),K(+)-ATPase is simultaneous with a conformational change detected by tryptophan and 1-aniline-8-naphtalenesulfonate (ANS) fluorescence. The kinetic coefficient of thermal inactivation was affected by the presence of Na(+) and K(+) (or Rb(+)) and the temperature of the preincuabtion media. Our results show that K(+) or Rb(+) stabilize the enzyme, while Na(+) decreases the stability of Na(+),K(+)-ATPase. Both effects are exerted by the specific binding of these cations to the pump. Also, we provided strong evidence that the Rb(+) (or K(+)) stabilization effect is due to the occlusion of these cations into the enzyme. Here, we proposed a minimal kinetic model that explains the behavior observed in the experimental results and allows a better understanding of the results presented by other researchers. The thermal inactivation process was also analyzed according to Kramer's theory.
    MeSH term(s) Anilino Naphthalenesulfonates/chemistry ; Cations/chemistry ; Kinetics ; Potassium/chemistry ; Protein Stability ; Rubidium/chemistry ; Sodium/chemistry ; Sodium-Potassium-Exchanging ATPase/chemistry ; Sodium-Potassium-Exchanging ATPase/metabolism ; Spectrometry, Fluorescence ; Temperature ; Tryptophan/chemistry
    Chemical Substances Anilino Naphthalenesulfonates ; Cations ; 1-anilino-8-naphthalenesulfonate (630I4V6051) ; Tryptophan (8DUH1N11BX) ; Sodium (9NEZ333N27) ; Sodium-Potassium-Exchanging ATPase (EC 3.6.3.9) ; Rubidium (MLT4718TJW) ; Potassium (RWP5GA015D)
    Language English
    Publishing date 2012-03-15
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/jp2124108
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