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Moschini R, Balestri F, Cappiello M, Signore G, Mura U, Del-Corso A. Ribose Intake as Food Integrator: Is It a Really Convenient Practice? Biomolecules 2022; 12:biom12121775. [PMID: 36551203 PMCID: PMC9776227 DOI: 10.3390/biom12121775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/07/2022] [Accepted: 11/22/2022] [Indexed: 12/02/2022] Open
Abstract
Reports concerning the beneficial effects of D-ribose administration in cardiovascular and muscle stressful conditions has led to suggestions for the use of ribose as an energizing food supplement for healthy people. However, this practice still presents too many critical issues, suggesting that caution is needed. In fact, there are many possible negative effects of this sugar that we believe are underestimated, if not neglected, by the literature supporting the presentation of the product to the market. Here, the risks deriving from the use of free ribose as ATP source, forcing ribose-5-phosphate to enter into the pentose phosphate pathway, is emphasized. On the basis of the remarkable glycation capacity of ribose, the easily predictable cytotoxic effect of the molecule is also highlighted.
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Affiliation(s)
- Roberta Moschini
- Biochemistry Unit, Department of Biology, University of Pisa, Via San Zeno, 51, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
| | - Francesco Balestri
- Biochemistry Unit, Department of Biology, University of Pisa, Via San Zeno, 51, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
| | - Mario Cappiello
- Biochemistry Unit, Department of Biology, University of Pisa, Via San Zeno, 51, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
| | - Giovanni Signore
- Biochemistry Unit, Department of Biology, University of Pisa, Via San Zeno, 51, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
| | - Umberto Mura
- Biochemistry Unit, Department of Biology, University of Pisa, Via San Zeno, 51, 56127 Pisa, Italy
- Correspondence:
| | - Antonella Del-Corso
- Biochemistry Unit, Department of Biology, University of Pisa, Via San Zeno, 51, 56127 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
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Bisoi A, Sarkar S, Chandra Singh P. Contrasting Effect of Salts on the Binding of Antimalarial Drug Hydroxychloroquine with Different Sequences of Duplex DNA. J Phys Chem B 2022; 126:5605-5612. [PMID: 35867068 DOI: 10.1021/acs.jpcb.2c02755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydroxychloroquine (HCQ) is an important antimalarial drug which functions plausibly by targeting the DNA of parasites. Salts play a crucial role in the functionality of various biological processes. Hence, the effect of salts (NaCl and MgCl2) on the binding of HCQ with AT- and CG-DNAs as well as the binding-induced stability of both sequences of DNAs have been investigated using the spectroscopic and molecular dynamics (MD) simulation methods. It has been found that the effect of salts on the binding of HCQ is highly sensitive to the nature of ions as well as DNA sequences. The effect of ions is opposite for the binding of AT- and CG-DNAs as the presence of Mg2+ ions enhances the binding of HCQ with AT-DNA, whereas the binding of HCQ with CG-DNA gets decreased on the addition of both ions. Similarly, the presence of Mg2+ enhances the stabilization of HCQ-bound AT-DNA, whereas the effect is opposite for the CG-DNA in the presence of both the ions. The MD simulation study suggests that the hydration states of both ions are different and they interact differently in the minor and major grooves of both the sequences of DNA which may be one of the reasons for the different binding of HCQ with these two sequences of DNA in the presence of salts. The information about the effect of salts on the binding of HCQ with DNAs in a sequence-specific manner may be useful in understanding the mechanism of the action and toxicity effect of HCQ against malaria.
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Affiliation(s)
- Asim Bisoi
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Sunipa Sarkar
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Prashant Chandra Singh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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Lin LL, Lu BY, Chi MC, Huang YF, Lin MG, Wang TF. Activation and thermal stabilization of a recombinant γ-glutamyltranspeptidase from Bacillus licheniformis ATCC 27811 by monovalent cations. Appl Microbiol Biotechnol 2022; 106:1991-2006. [PMID: 35230495 DOI: 10.1007/s00253-022-11836-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 02/08/2022] [Accepted: 02/12/2022] [Indexed: 12/27/2022]
Abstract
The regulation of enzyme activity through complexation with certain metal ions plays an important role in many biological processes. In addition to divalent metals, monovalent cations (MVCs) frequently function as promoters for efficient biocatalysis. Here, we examined the effect of MVCs on the enzymatic catalysis of a recombinant γ-glutamyltranspeptidase (BlrGGT) from Bacillus licheniformis ATCC 27,811 and the application of a metal-activated enzyme to L-theanine synthesis. The transpeptidase activity of BlrGGT was enhanced by Cs+ and Na+ over a broad range of concentrations with a maximum of 200 mM. The activation was essentially independent of the ionic radius, but K+ contributed the least to enhancing the catalytic efficiency. The secondary structure of BlrGGT remained mostly unchanged in the presence of different concentrations of MVCs, but there was a significant change in its tertiary structure under the same conditions. Compared with the control, the half-life (t1/2) of the Cs+-enriched enzyme at 60 and 65 °C was shown to increase from 16.3 and 4.0 min to 74.5 and 14.3 min, respectively. The simultaneous addition of Cs+ and Mg2+ ions exerted a synergistic effect on the activation of BlrGGT. This was adequately reflected by an improvement in the conversion of substrates to L-theanine by 3.3-15.1% upon the addition of 200 mM MgCl2 into a reaction mixture comprising the freshly desalted enzyme (25 μg/mL), 250 mM L-glutamine, 600 mM ethylamine, 200 mM each of the MVCs, and 50 mM borate buffer (pH 10.5). Taken together, our results provide interesting insights into the complexation of MVCs with BlrGGT and can therefore be potentially useful to the biocatalytic production of naturally occurring γ-glutamyl compounds. KEY POINTS: • The transpeptidase activity of B. licheniformis γ-glutamyltranspeptidase can be activated by monovalent cations. • The thermal stability of the enzyme was profoundly increased in the presence of 200 mM Cs+. • The simultaneous addition of Cs+and Mg2+ions to the reaction mixture improves L-theanine production.
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Affiliation(s)
- Long-Liu Lin
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Bo-Yuan Lu
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Meng-Chun Chi
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Yu-Fen Huang
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Min-Guan Lin
- Institute of Molecular Biology, Academia Sinica, Nangang District, Taipei City, 11529, Taiwan
| | - Tzu-Fan Wang
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan.
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Abstract
Neoplastic transformation is reportedly associated with alterations of the potassium transport across plasma and intracellular membranes. These alterations have been identified as crucial elements of the tumourigenic reprogramming of cells. Potassium channels may contribute to cancer initiation, malignant progression and therapy resistance of tumour cells. The book chapter focusses on (oncogenic) potassium channels frequently upregulated in different tumour entities, upstream and downstream signalling of these channels, their contribution to the maintenance of cancer stemness and the formation of an immunosuppressive tumour microenvironment. In addition, their role in adaptation to tumour hypoxia, metabolic reprogramming, as well as tumour spreading and metastasis is discussed. Finally, we discuss how (oncogenic) potassium channels may confer treatment resistance of tumours against radiation and chemotherapy and thus might be harnessed for new therapy strategies, for instance, by repurposing approved drugs known to target potassium channels.
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Artsemyeva JN, Remeeva EA, Buravskaya TN, Konstantinova ID, Esipov RS, Miroshnikov AI, Litvinko NM, Mikhailopulo IA. Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases. Beilstein J Org Chem 2020; 16:2607-2622. [PMID: 33133292 PMCID: PMC7588730 DOI: 10.3762/bjoc.16.212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 10/05/2020] [Indexed: 12/20/2022] Open
Abstract
In the present work, we suggested anion exchange resins in the phosphate form as a source of phosphate, one of the substrates of the phosphorolysis of uridine, thymidine, and 1-(β-ᴅ-arabinofuranosyl)uracil (Ara-U) catalyzed by recombinant E. coli uridine (UP) and thymidine (TP) phosphorylases. α-ᴅ-Pentofuranose-1-phosphates (PF-1Pis) obtained by phosphorolysis were used in the enzymatic synthesis of nucleosides. It was found that phosphorolysis of uridine, thymidine, and Ara-U in the presence of Dowex® 1X8 (phosphate; Dowex-nPi) proceeded smoothly in the presence of magnesium cations in water at 20-50 °C for 54-96 h giving rise to quantitative formation of the corresponding pyrimidine bases and PF-1Pis. The resulting PF-1Pis can be used in three routes: (1) preparation of barium salts of PF-1Pis, (2) synthesis of nucleosides by reacting the crude PF-1Pi with an heterocyclic base, and (3) synthesis of nucleosides by reacting the ionically bound PF-1Pi to the resin with an heterocyclic base. These three approaches were tested in the synthesis of nelarabine, kinetin riboside, and cladribine with good to excellent yields (52-93%).
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Affiliation(s)
- Julia N Artsemyeva
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141 Minsk, Acad. Kuprevicha 5/2, Republic of Belarus
| | - Ekaterina A Remeeva
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141 Minsk, Acad. Kuprevicha 5/2, Republic of Belarus
| | - Tatiana N Buravskaya
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141 Minsk, Acad. Kuprevicha 5/2, Republic of Belarus
| | - Irina D Konstantinova
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 GSP-7, Moscow B-437, Russian Federation
| | - Roman S Esipov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 GSP-7, Moscow B-437, Russian Federation
| | - Anatoly I Miroshnikov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 GSP-7, Moscow B-437, Russian Federation
| | - Natalia M Litvinko
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141 Minsk, Acad. Kuprevicha 5/2, Republic of Belarus
| | - Igor A Mikhailopulo
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141 Minsk, Acad. Kuprevicha 5/2, Republic of Belarus
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An Evolutionary Marker of the Ribokinase Superfamily Is Responsible for Zinc-Mediated Regulation of Human Pyridoxal Kinase. Catalysts 2020. [DOI: 10.3390/catal10050555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The ribokinase superfamily catalyzes the phosphorylation of a vast diversity of substrates, and its members are characterized by the conservation of a common structural fold along with highly conserved sequence motifs responsible for phosphoryl transfer (GXGD) and stabilization of the metal-nucleotide complex (NXXE). Recently, a third motif (HXE) exclusive from ADP-dependent enzymes was identified, with its glutamic acid participating in water-mediated interactions with the metal-nucleotide complex and in stabilization of the ternary complex during catalysis. In this work, we bioinformatically determine that the aspartic acid of another motif (DPV), exclusively found in hydroxyethyl thiazole (THZK), hydroxymethyl pyrimidine (HMPK) and pyridoxal kinases (PLK), is structurally equivalent to the acidic residue in the HXE motif. Moreover, this residue is highly conserved among all ribokinase superfamily members. To determine whether the functional role of the DPV motif is similar to the HXE motif, we employed molecular dynamics simulations using crystal structures of phosphoryl donor substrate-complexed THZK and PLK, showing that its aspartic acid participated in water-mediated or direct interactions with the divalent metal of the metal-nucleotide complex. Lastly, enzyme kinetic assays on human PLK, an enzyme that utilizes zinc, showed that site-directed mutagenesis of the aspartic acid from the DPV motif abolishes the inhibition of this enzyme by increasing free zinc concentrations. Altogether, our results highlight that the DPV and HXE motifs are evolutionary markers of the functional and structural divergence of the ribokinase superfamily and evidence the role of the DPV motif in the interaction with both free and nucleotide-complexed divalent metals in the binding site of these enzymes.
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The furanosidic scaffold of d-ribose: a milestone for cell life. Biochem Soc Trans 2020; 47:1931-1940. [PMID: 31697320 DOI: 10.1042/bst20190749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/03/2019] [Accepted: 10/07/2019] [Indexed: 01/15/2023]
Abstract
The recruitment of the furanosidic scaffold of ribose as the crucial step for nucleotides and then for nucleic acids synthesis is presented. Based on the view that the selection of molecules to be used for relevant metabolic purposes must favor structurally well-defined molecules, the inadequacy of ribose as a preferential precursor for nucleotides synthesis is discussed. The low reliability of ribose in its furanosidic hemiacetal form must have played ab initio against the choice of d-ribose for the generation of d-ribose-5-phosphate, the fundamental precursor of the ribose moiety of nucleotides. The latter, which is instead generated through the 'pentose phosphate pathway' is strictly linked to the affordable and reliable pyranosidic structure of d-glucose.
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Gatreddi S, Pillalamarri V, Vasudevan D, Addlagatta A, Qureshi IA. Unraveling structural insights of ribokinase from Leishmania donovani. Int J Biol Macromol 2019; 136:253-265. [PMID: 31170491 DOI: 10.1016/j.ijbiomac.2019.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/29/2019] [Accepted: 06/01/2019] [Indexed: 11/16/2022]
Abstract
Ribokinase (RK) is an ATP dependent sugar kinase that enables the entry of ribose in the metabolism. Leishmania accumulates ribose into the cytosol through hydrolysis of nucleosides and by transport from the extracellular environment. Activation by RK is critical to mobilize the ribose into the metabolism of Leishmania. To understand the catalytic role, the crystal structure of RK (LdRK) from L. donovani was determined in the apo and complex forms with several nucleotides (ATP, AMPPCP and ADP) in the presence of Na+ ion. The dual insertion of five amino acid stretches makes LdRK structurally unique from other reported structures of RKs. The structure of LdRK-ATP provided the basis for positioning of γ-phosphate of ATP by conserved -GAGD- motif. Liganded and unliganded structures of LdRK exists in similar conformation, which suggests binding of nucleotides does not make any significant conformational changes in nucleotide-bound structures. Substitution of a conserved asparagine with phenylalanine in ribose binding pocket differentiates the LdRK from other RKs. Glycerol molecule bound in the substrate binding pocket mimics the enzyme-substrate interactions but in turn, hampers the binding of ribose to LdRK. Comparative structural analysis revealed the flexibility of γ-phosphate, which adopts multiple conformations in the absence of divalent metal ion and ribose. Similar to other RKs, LdRK is also dependent on monovalent as well as divalent cations for its catalytic activity.
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Affiliation(s)
- Santhosh Gatreddi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India
| | - Vijaykumar Pillalamarri
- CSIR-Indian Institute of Chemical Technology, Applied Biology, Hyderabad 500 007, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Rafi Marg, New Delhi 110001, India
| | | | - Anthony Addlagatta
- CSIR-Indian Institute of Chemical Technology, Applied Biology, Hyderabad 500 007, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Rafi Marg, New Delhi 110001, India
| | - Insaf Ahmed Qureshi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India.
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Gatreddi S, Are S, Qureshi IA. Ribokinase from Leishmania donovani: purification, characterization and X-ray crystallographic analysis. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2018; 74:99-104. [PMID: 29400319 DOI: 10.1107/s2053230x18000109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/02/2018] [Indexed: 11/11/2022]
Abstract
Leishmania is an auxotrophic protozoan parasite which acquires D-ribose by transporting it from the host cell and also by the hydrolysis of nucleosides. The enzyme ribokinase (RK) catalyzes the first step of ribose metabolism by phosphorylating D-ribose using ATP to produce D-ribose-5-phosphate. To understand its structure and function, the gene encoding RK from L. donovani was cloned, expressed and purified using affinity and size-exclusion chromatography. Circular-dichroism spectroscopy of the purified protein showed comparatively more α-helix in the secondary-structure content, and thermal unfolding revealed the Tm to be 317.2 K. Kinetic parameters were obtained by functional characterization of L. donovani RK, and the Km values for ribose and ATP were found to be 296 ± 36 and 116 ± 9.0 µM, respectively. Crystals obtained by the hanging-drop vapour-diffusion method diffracted to 1.95 Å resolution and belonged to the hexagonal space group P61, with unit-cell parameters a = b = 100.25, c = 126.77 Å. Analysis of the crystal content indicated the presence of two protomers in the asymmetric unit, with a Matthews coefficient (VM) of 2.45 Å3 Da-1 and 49.8% solvent content. Further study revealed that human counterpart of this protein could be used as a template to determine the first three-dimensional structure of the RK from trypanosomatid parasites.
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Affiliation(s)
- Santhosh Gatreddi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Professor C. R. Rao Road, Hyderabad 500 046, India
| | - Sayanna Are
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Professor C. R. Rao Road, Hyderabad 500 046, India
| | - Insaf Ahmed Qureshi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Professor C. R. Rao Road, Hyderabad 500 046, India
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Riggs JW, Cavales PC, Chapiro SM, Callis J. Identification and biochemical characterization of the fructokinase gene family in Arabidopsis thaliana. BMC PLANT BIOLOGY 2017; 17:83. [PMID: 28441933 PMCID: PMC5405513 DOI: 10.1186/s12870-017-1031-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 04/12/2017] [Indexed: 05/09/2023]
Abstract
BACKGROUND Fructose is an abundant sugar in plants as it is a breakdown product of both major sucrose-cleaving enzymes. To enter metabolism, fructose is phosphorylated by a fructokinase (FRK). Known FRKs are members of a diverse family of carbohydrate/purine kinases known as the phosphofructokinase B (pfkB) family. The complete complement of active fructokinases has not been reported for any plant species. RESULTS Protein sequence analysis of the 22 Arabidopsis thaliana pfkB members identified eight highly related predicted proteins, including one with previously demonstrated FRK activity. For one, At1g50390, the predicted open reading frame is half the size of active FRKs, and only incompletely spliced RNAs were identified, which led to a premature stop codon, both indicating that this gene does not produce active FRK. The remaining seven proteins were expressed in E. coli and phosphorylated fructose specifically in vitro leading us to propose a unifying nomenclature (FRK1-7). Substrate inhibition was observed for fructose in all FRKs except FRK1. Fructose binding was on the same order of magnitude for FRK1-6, between 260 and 480 μM. FRK7 was an outlier with a fructose Km of 12 μM. ATP binding was similar for all FRKs and ranged between 52 and 280 μM. YFP-tagged AtFRKs were cytosolic, except plastidic FRK3. T-DNA alleles with non-detectable wild-type RNAs in five of the seven active FRK genes produced no overt phenotype. We extended our sequence comparisons to include putative FRKs encoded in other plant sequenced genomes. We observed that different subgroups expanded subsequent to speciation. CONCLUSIONS Arabidopsis thaliana as well as all other plant species analyzed contain multiple copies of genes encoding FRK activity. Sequence comparisons among multiple species identified a minimal set of three distinct FRKs present on all species investigated including a plastid-localized form. The selective expansion of specific isozymes results in differences in FRK gene number among species. AtFRKs exhibit substrate inhibition, typical of their mammalian counterparts with the single AtFRK1 lacking this property, suggesting it may have a distinct in vivo role. Results presented here provide a starting point for the engineering of specific FRKs to affect biomass production.
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Affiliation(s)
- John W. Riggs
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, 1 Shields Ave, Davis, CA 95616 USA
| | - Philip C. Cavales
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, 1 Shields Ave, Davis, CA 95616 USA
| | - Sonia M. Chapiro
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, 1 Shields Ave, Davis, CA 95616 USA
- Present Address: Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
- Present Address: Joint Bioenergy Institute, Emeryville, CA 94608 USA
| | - Judy Callis
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, 1 Shields Ave, Davis, CA 95616 USA
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Riggs JW, Rockwell NC, Cavales PC, Callis J. Identification of the Plant Ribokinase and Discovery of a Role for Arabidopsis Ribokinase in Nucleoside Metabolism. J Biol Chem 2016; 291:22572-22582. [PMID: 27601466 DOI: 10.1074/jbc.m116.754689] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 09/06/2016] [Indexed: 12/30/2022] Open
Abstract
Ribose can be used for energy or as a component of several important biomolecules, but for it to be used in either capacity it must first be phosphorylated by ribokinase (RBSK). RBSK proteins are part of the phosphofructokinase-B (pfkB) family of carbohydrate kinases. Sequence comparisons of pfkB proteins from the model plant Arabidopsis thaliana with the human and Escherichia coli RBSK identified a single candidate RBSK, At1g17160 (AtRBSK). AtRBSK is more similar to predicted RBSKs from other plant species and known mammalian and prokaryotic RBSK than to all other PfkB proteins in Arabidopsis AtRBSK contains a predicted chloroplast transit peptide, and we confirmed plastid localization using AtRBSK fused to YFP. Structure prediction software verified that the AtRBSK sequence mapped onto a known RBSK structure. Kinetic parameters of purified recombinant AtRBSK were determined to be Kmribose = 150 μm ± 17 μm, KmATP = 45 μm ± 5.6 μm, and kcat = 2.0 s-1 Substrate inhibition was observed for AtRBSK (KiATP = 2.44 mm ± 0.36 mm), as has been demonstrated for other RBSK proteins. Ribose accumulated in Arabidopsis plants lacking AtRBSK. Such plants grew normally unless media was supplemented with ribose, which led to chlorosis and growth inhibition. Both chlorosis and ribose accumulation were abolished upon the introduction of a transgene expressing AtRBSK-MYC, demonstrating that the loss of protein is responsible for ribose hypersensitivity. Ribose accumulation in plants lacking AtRBSK was reduced in plants also deficient in the nucleoside ribohydrolase NSH1, linking AtRBSK activity to nucleoside metabolism.
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Affiliation(s)
- John W Riggs
- From the Department of Molecular and Cellular Biology, University of California, Davis, California 95616
| | - Nathan C Rockwell
- From the Department of Molecular and Cellular Biology, University of California, Davis, California 95616
| | - Philip C Cavales
- From the Department of Molecular and Cellular Biology, University of California, Davis, California 95616
| | - Judy Callis
- From the Department of Molecular and Cellular Biology, University of California, Davis, California 95616
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Abarca-Lagunas MJ, Rivas-Pardo JA, Ramírez-Sarmiento CA, Guixé V. Dissecting the functional roles of the conserved NXXE and HXE motifs of the ADP-dependent glucokinase fromThermococcus litoralis. FEBS Lett 2015; 589:3271-6. [DOI: 10.1016/j.febslet.2015.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 09/11/2015] [Accepted: 09/20/2015] [Indexed: 11/28/2022]
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