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Abstract
The evaluation of enzyme activities, especially their capacities, represents an important step towards the modelling of biochemical pathways in living organisms. The implementation of microplate technology enables the determination of up to >50 enzymes in relatively large numbers of samples and in various biological materials. Most of these enzymes are involved in central metabolism and several pathways are entirely covered. Direct or indirect assays can be used, as well as highly sensitive assays, depending on the abundance of the enzymes under study. To exemplify such methods, protocols for UDP-glucose pyrophosphorylase (E.C. 2.7.7.9) operating in real time and for pyrophosphate:fructose-6-phosphate 1-phosphotransferase (E.C. 2.7.1.90) are presented.
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2
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Brüser A, Kirchberger J, Schöneberg T. Altered allosteric regulation of muscle 6-phosphofructokinase causes Tarui disease. Biochem Biophys Res Commun 2012; 427:133-7. [PMID: 22995305 DOI: 10.1016/j.bbrc.2012.09.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 09/06/2012] [Indexed: 11/18/2022]
Abstract
Tarui disease is a glycogen storage disease (GSD VII) and characterized by exercise intolerance with muscle weakness and cramping, mild myopathy, myoglobinuria and compensated hemolysis. It is caused by mutations in the muscle 6-phosphofructokinase (Pfk). Pfk is an oligomeric, allosteric enzyme which catalyzes one of the rate-limiting steps of the glycolysis: the phosphorylation of fructose 6-phosphate at position 1. Pfk activity is modulated by a number of regulators including adenine nucleotides. Recent crystal structures from eukaryotic Pfk displayed several allosteric adenine nucleotide binding sites. Functional studies revealed a reciprocal linkage between the activating and inhibitory allosteric binding sites. Herein, we showed that Asp(543)Ala, a naturally occurring disease-causing mutation in the activating binding site, causes an increased efficacy of ATP at the inhibitory allosteric binding site. The reciprocal linkage between the activating and inhibitory binding sites leads to reduced enzyme activity and therefore to the clinical phenotype. Pharmacological blockage of the inhibitory allosteric binding site or highly efficient ligands for the activating allosteric binding site may be of therapeutic relevance for patients with Tarui disease.
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Affiliation(s)
- Antje Brüser
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
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3
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Abrantes JL, Alves CM, Costa J, Almeida FCL, Sola-Penna M, Fontes CFL, Souza TML. Herpes simplex type 1 activates glycolysis through engagement of the enzyme 6-phosphofructo-1-kinase (PFK-1). Biochim Biophys Acta Mol Basis Dis 2012; 1822:1198-206. [PMID: 22542512 DOI: 10.1016/j.bbadis.2012.04.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 04/09/2012] [Accepted: 04/12/2012] [Indexed: 01/17/2023]
Abstract
UNLABELLED Viruses such as HIV, HCV, Mayaro and HCMV affect cellular metabolic pathways, including glycolysis. Although some studies have suggested that the inhibition of glycolysis affects HSV-1 replication and that HSV-1-infected eyes have increased lactate production, the mechanisms by which HSV-1 induces glycolysis have never been investigated in detail. In this study, we observed an increase in glucose uptake, lactate efflux and ATP content in HSV-1-infected cells. HSV-1 triggered a MOI-dependent increase in the activity of phosphofructokinase-1 (PFK-1), a key rate-limiting enzyme of the glycolytic pathway. After HSV-1 infection, we observed increased PFK-1 expression, which increased PFK-1 total activity, and the phosphorylation of this enzyme at serine residues. HSV-1-induced glycolysis was associated with increased ATP content, and these events were critical for viral replication. In summary, our results suggest that HSV-1 triggers glycolysis through a different mechanism than other herpesviruses, such as HCMV. Thus, this study contributes to a better understanding of HSV-1 pathogenesis and provides insights into novel targets for antiviral therapy. HIGHLIGHTS ►HSV-1 activates glycolysis by PFK-1 activation. ►In HSV-1-infected cells PFK-1 synthesis is up-regulated and phosphorylated at serine residues. ►PFK-1 knockdown impairs HSV-1 replication. ►HSV-1-mediated glycolysis activation increases ATP content.
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Affiliation(s)
- Juliana L Abrantes
- Laboratório de Estrutura e Regulação de Proteínas e ATPases, Programa de Pós-Graduação em Química Biológica, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, RJ, Brazil.
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4
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Coelho WS, Costa KC, Sola-Penna M. Serotonin stimulates mouse skeletal muscle 6-phosphofructo-1-kinase through tyrosine-phosphorylation of the enzyme altering its intracellular localization. Mol Genet Metab 2007; 92:364-70. [PMID: 17720578 DOI: 10.1016/j.ymgme.2007.07.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Accepted: 07/11/2007] [Indexed: 11/24/2022]
Abstract
Serotonin (5-HT) is a hormone implicated in the regulation of many physiological and pathological events. One of its most intriguing properties is the ability to up-regulate mitosis. Moreover, it has been shown that 5-HT stimulate glucose uptake on skeletal muscle, suggesting that 5-HT may regulate glucose metabolism of peripheric tissues. Here we demonstrate that 5-HT stimulates skeletal muscle 6-phosphofructo-1-kinase (PFK) activity in a dose-response manner, through 5-HT(2A) receptor subtype. Maximal activation of the enzyme (2.5-fold compared to control) is achieved in the presence of 25pM 5-HT, increasing both PFK maximal velocity and affinity for the substrate fructose-6-phosphate. These effects occur due to tyrosine phosphorylation of the enzyme that is 2-fold enhanced upon 5-HT stimulation of skeletal muscles preparation. Once 5-HT-induced tyrosine phosphorylation of PFK is prevented by genistein, a tyrosine kinase inhibitor, the hormone stimulatory effect on PFK is abrogated. Wortmannin, a phosphatidylinositol-3-kinase (PI3K) inhibitor, does not interfere on 5-HT-induced stimulation of PFK, supporting that the observed effects are independent on insulin signaling pathway. Furthermore, 5-HT promotes the association of PFK to the muscle f-actin, suggesting that the hormone alters PFK intracellular distribution, favoring its association to the cytoskeleton. Altogether, our results support evidences that 5-HT augments skeletal muscle glucose consumption through stimulation of glycolysis key regulatory enzyme, PFK, throughout tyrosine phosphorylation and intracellular redistribution of the enzyme.
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Affiliation(s)
- Wagner Santos Coelho
- Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ 21941-590, Brazil
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5
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Costa Leite T, Da Silva D, Guimarães Coelho R, Zancan P, Sola-Penna M. Lactate favours the dissociation of skeletal muscle 6-phosphofructo-1-kinase tetramers down-regulating the enzyme and muscle glycolysis. Biochem J 2007; 408:123-30. [PMID: 17666012 PMCID: PMC2049071 DOI: 10.1042/bj20070687] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
For a long period lactate was considered as a dead-end product of glycolysis in many cells and its accumulation correlated with acidosis and cellular and tissue damage. At present, the role of lactate in several physiological processes has been investigated based on its properties as an energy source, a signalling molecule and as essential for tissue repair. It is noteworthy that lactate accumulation alters glycolytic flux independently from medium acidification, thereby this compound can regulate glucose metabolism within cells. PFK (6-phosphofructo-1-kinase) is the key regulatory glycolytic enzyme which is regulated by diverse molecules and signals. PFK activity is directly correlated with cellular glucose consumption. The present study shows the property of lactate to down-regulate PFK activity in a specific manner which is not dependent on acidification of the medium. Lactate reduces the affinity of the enzyme for its substrates, ATP and fructose 6-phosphate, as well as reducing the affinity for ATP at its allosteric inhibitory site at the enzyme. Moreover, we demonstrated that lactate inhibits PFK favouring the dissociation of enzyme active tetramers into less active dimers. This effect can be prevented by tetramer-stabilizing conditions such as the presence of fructose 2,6-bisphosphate, the binding of PFK to f-actin and phosphorylation of the enzyme by protein kinase A. In conclusion, our results support evidence that lactate regulates the glycolytic flux through modulating PFK due to its effects on the enzyme quaternary structure.
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Affiliation(s)
- Tiago Costa Leite
- *Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
- †Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
| | - Daniel Da Silva
- *Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
| | - Raquel Guimarães Coelho
- †Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
| | - Patricia Zancan
- *Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
| | - Mauro Sola-Penna
- *Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590
- To whom correspondence should be addressed (email )
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6
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Abstract
Here we describe the crystal structures of the NAD kinase (LmNADK1) from Listeria monocytogenes in complex with its substrate NAD, its product NADP, or two synthesized NAD mimics. We identified one of the NAD mimics, di-adenosine diphosphate, as a new substrate for LmNADK1, whereas we showed that the closely related compound di-5'-thioadenosine is a novel non-natural inhibitor for this enzyme. These structures suggest a mechanism involving substrate-assisted catalysis. Indeed, sequence/structure comparison and directed mutagenesis have previously shown that NAD kinases (NADKs) and the distantly related 6-phosphofructokinases share the same catalytically important GGDGT motif. However, in this study we have shown that these enzymes use the central aspartate of this motif differently. Although this acidic residue chelates the catalytic Mg(2+) ion in 6-phosphofructokinases, it activates the phospho-acceptor (NAD) in NADKs. Sequence/structure comparisons suggest that the role of this aspartate would be conserved in NADKs and the related sphingosine and diacylglycerol kinases.
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Affiliation(s)
- Guillaume Poncet-Montange
- Atelier de Bio- et Chimie Informatique Structurale, Centre de Biochimie Structurale, UMR 5048/CNRS, Universités Montpellier 1 et 2, 29 rue de Navacelles, Montpellier, France
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7
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Benjamin S, Radermacher M, Bär J, Edelmann A, Ruiz T. Structures of S. pombe phosphofructokinase in the F6P-bound and ATP-bound states. J Struct Biol 2007; 159:498-506. [PMID: 17643314 PMCID: PMC3586532 DOI: 10.1016/j.jsb.2007.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 06/04/2007] [Accepted: 06/05/2007] [Indexed: 11/26/2022]
Abstract
Phosphofructokinase (Pfk1; EC 2.7.1.11) is the third enzyme of the glycolytic pathway catalyzing the formation of fructose-1,6-bisphosphate from fructose-6-phosphate (F6P) and ATP. Schizosaccharomyces pombe Pfk1 is a homo-octameric enzyme of 800 kDa molecular weight, distinct from its yeast counterparts which are mostly hetero-octameric enzymes composed of two different subunits. Having an "open" conformation and a tendency to aggregate into higher oligomeric structures, the S. pombe enzyme shows similarities to the mammalian muscle Pfk1. It has been proposed that due to the distinct N-terminal region of the S. pombe subunit, the oligomeric organization of subunits in this enzyme is different from other yeast phosphofructokinases. Electron microscopy studies were carried out to reveal the quaternary structure of the homo-octameric Pfk1 from S. pombe in the F6P-bound and in the ATP-bound state. Random conical tilt data sets have been collected from deep stain preparations of the enzyme in both states. The 0 degrees tilt images have been separated into different classes and a 3D reconstruction has been calculated for each class from the high tilt images. Our results confirm the presence of a variety of views of the particle, most of which can be interpreted as views of the molecule rotating around its long axis. Despite the biochemical differences, the structure of phosphofructokinase from S. pombe in the presence of either F6P or ATP is similar to the hetero-octameric structure of phosphofructokinase from Saccharomyces cerevisiae. The molecule can be described as composed of two subdomains, connected by two well-defined densities. We have been able to establish a correlation between the kinetic behavior and the structural conformation of Pfk1.
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Affiliation(s)
- Shaun Benjamin
- University of Vermont, College of Medicine, Dept. of Molecular Physiology and Biophysics, Burlington, VT 05405
| | - Michael Radermacher
- University of Vermont, College of Medicine, Dept. of Molecular Physiology and Biophysics, Burlington, VT 05405
| | - Jörg Bär
- Institut für Biochemie, Medizinische Fakultät, Universität Leipzig, Johannisallee 30, D-04103 Leipzig, Germany
| | - Anke Edelmann
- Institut für Biochemie, Medizinische Fakultät, Universität Leipzig, Johannisallee 30, D-04103 Leipzig, Germany
| | - Teresa Ruiz
- University of Vermont, College of Medicine, Dept. of Molecular Physiology and Biophysics, Burlington, VT 05405
- To whom correspondence should be addressed: Dr. Teresa Ruiz, University of Vermont, College of Medicine, Dept. of Molecular Physiology and Biophysics, Burlington, VT 05405, e-mail
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8
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Tanneberger K, Kirchberger J, Bär J, Schellenberger W, Rothemund S, Kamprad M, Otto H, Schöneberg T, Edelmann A. A novel form of 6-phosphofructokinase. Identification and functional relevance of a third type of subunit in Pichia pastoris. J Biol Chem 2007; 282:23687-97. [PMID: 17522059 DOI: 10.1074/jbc.m611547200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Classically, 6-phosphofructokinases are homo- and hetero-oligomeric enzymes consisting of alpha subunits and alpha/beta subunits, respectively. Herein, we describe a new form of 6-phosphofructokinase (Pfk) present in several Pichia species, which is composed of three different types of subunit, alpha, beta, and gamma. The sequence of the gamma subunit shows no similarity to classic Pfk subunits or to other known protein sequences. In-depth structural and functional studies revealed that the gamma subunit is a constitutive component of Pfk from Pichia pastoris (PpPfk). Analyses of the purified PpPfk suggest a heterododecameric assembly from the three different subunits. Accordingly, it is the largest and most complex Pfk identified yet. Although, the gamma subunit is not required for enzymatic activity, the gamma subunit-deficient mutant displays a decreased growth on nutrient limitation and reduced cell flocculation when compared with the P. pastoris wild-type strain. Subsequent characterization of purified Pfks from wild-type and gamma subunit-deficient strains revealed that the allosteric regulation of the PpPfk by ATP, fructose 2,6-bisphosphate, and AMP is fine-tuned by the gamma subunit. Therefore, we suggest that the gamma subunit contributes to adaptation of P. pastoris to energy resources.
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Affiliation(s)
- Katrin Tanneberger
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, 04103 Leipzig, Germany
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9
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Bárcena M, Radermacher M, Bär J, Kopperschläger G, Ruiz T. The structure of the ATP-bound state of S. cerevisiae phosphofructokinase determined by cryo-electron microscopy. J Struct Biol 2007; 159:135-43. [PMID: 17493831 PMCID: PMC3586225 DOI: 10.1016/j.jsb.2007.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2006] [Revised: 03/26/2007] [Accepted: 03/27/2007] [Indexed: 12/01/2022]
Abstract
Phosphofructokinase (Pfk1, EC 2.7.1.11) plays a key regulatory role in the glycolytic pathway. The combination of X-ray crystallographic and biochemical data has provided an understanding of the different conformational changes that occur between the active and inhibited states of the bacterial enzyme, and of the role of the two bacterial effectors. Eukaryotic phosphofructokinases exhibit a far more sophisticated regulatory mechanism, they are more complex structures regulated by a large number of effectors (around 20). Saccharomyces cerevisiae Pfk1 is an 835 kDa hetero-octamer which shows cooperative binding for fructose-6-phosphate (F6P) and non-cooperative binding for ATP. The 3D structure of the F6P-bound state was obtained by cryo-electron microscopy to 1.1 nm resolution. This electron microscopy structure, in combination with molecular replacement using the bacterial enzyme has helped provide initial phases to solve the X-ray structure of the F6P-bound state 12S yeast truncated-tetramer. Biochemical and small-angle X-ray scattering (SAXS) studies had indicated that Pfk1 underwent a large conformational change upon Mg-ATP binding. We have calculated a reconstruction using reference-based 3D projection alignment methods from 0 degrees images acquired from frozen-hydrated preparations of the enzyme in the presence of Mg-ATP. The ATP-bound structure is more extended or open, and the calculated radius of gyration of 7.33 nm (7.0 nm for F6P) is in good agreement with the SAXS data. There is a substantial decrease in the rotational angle between the top and bottom tetramers. Interestingly, all these changes have arisen from a reorientation of the alpha- and beta-subunits in the dimers. The interface region between the alpha- and beta-subunits is now approximately half the size of the one in the F6P-bound structure. This is the first time that the 3D structure of a eukaryotic Pfk1 has been visualized in its T-state (inhibited-state).
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Affiliation(s)
- Montserrat Bárcena
- University of Vermont, College of Medicine, Department of Molecular Physiology and Biophysics, Burlington, VT 05405, USA
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10
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Mediavilla D, Metón I, Baanante IV. Purification and kinetic properties of 6-phosphofructo-1-kinase from gilthead sea bream muscle. Biochim Biophys Acta Gen Subj 2006; 1770:706-15. [PMID: 17229526 DOI: 10.1016/j.bbagen.2006.11.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Revised: 11/27/2006] [Accepted: 11/28/2006] [Indexed: 10/23/2022]
Abstract
The kinetic properties of 6-phosphofructo-1-kinase (PFK) from skeletal muscle (PFKM) of gilthead sea bream (Sparus aurata) were studied, after 10,900-fold purification to homogeneity. The native enzyme had an apparent molecular mass of 662 kDa and is composed of 81 kDa subunits, suggesting a homooctameric structure. At physiological pH, S. aurata PFKM exhibited sigmoidal kinetics for the substrates, fructose-6-phosphate (fru-6-P) and ATP. Fructose-2,6-bisphosphate (fru-2,6-P(2)) converted the saturation curves for fru-6-P to hyperbolic, activated PFKM synergistically with other positive effectors of the enzyme such as AMP and ADP, and counteracted ATP and citrate inhibition. The fish enzyme showed differences regarding other animal PFKs: it is active as a homooctamer, and fru-2,6-P(2) and pH affected affinity for ATP. By monitoring incorporation of (32)P from ATP, we show that fish PFKM is a substrate for the cAMP-dependent protein kinase. The mechanism involved in PFKM activation by phosphorylation contrasts with previous observations in other species: it increased V(max) and did not affect affinity for fru-6-P. Unlike the mammalian muscle enzyme, our findings support that phosphorylation of PFKM may exert a major role during starvation in fish muscle.
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Affiliation(s)
- Dominica Mediavilla
- Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Diagonal 643, 08028 Barcelona, Spain
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11
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Mlakar T, Legisa M. citrate inhibition-resistant form of 6-phosphofructo-1-kinase from Aspergillus niger. Appl Environ Microbiol 2006; 72:4515-21. [PMID: 16820438 PMCID: PMC1489355 DOI: 10.1128/aem.00539-06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Accepted: 04/11/2006] [Indexed: 11/20/2022] Open
Abstract
Two forms of Aspergillus niger 6-phosphofructo-1-kinase (PFK1) have been described recently, the 85-kDa native enzyme and 49-kDa shorter fragment that is formed from the former by posttranslational modification. So far, kinetic characteristics have never been determined on the enzyme purified to near homogeneity. For the first time, kinetic parameters were determined for individual enzymes with respect to citrate inhibition. The native 85-kDa enzyme was found to be moderately inhibited by citrate, with the Ki value determined to be 1.5 mM, in the system with 5 mM Mg2+ ions, while increasing magnesium concentrations relieved the negative effect of citrate. An identical inhibition coefficient was determined also in the presence of ammonium ions, although ammonium acted as a strong activator of enzyme activity. On the other hand, the shorter fragment of PFK1 proved to be completely resistant to inhibition by citrate. Allosteric citrate binding sites were most probably lost after the truncation of the C-terminal part of the native protein, in which region some binding sites for inhibitor are known to be located. At near physiological conditions, characterized by low fructose-6-phosphate concentrations, a much higher efficiency of the shorter fragment was observed during an in vitro experiment. Since the enzyme became more susceptible to the positive control by specific ligands, while the negative control was lost after posttranslational modification, the shorter PFK1 fragment seems to be the enzyme most responsible for generating undisturbed metabolic flow through glycolysis in A. niger cells.
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Affiliation(s)
- Tina Mlakar
- National Institute of Chemistry, Department of Biotechnology, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
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12
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Zhou CQ, Wang JQ, Qian Z, Ma YH, Liu SQ. [Cloning, expression and characterization of the 6-phosphofructokinase from Thermoanaerobacter tengcongensis]. Wei Sheng Wu Xue Bao 2006; 46:249-54. [PMID: 16736586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The enzyme of 6-phosphofructokinase (PFK) is a key element in glycolysis, widely distributed in most eukaryote and prokaryote. Although the gene TTE1816 from Thermoanaerobacter tengcongenisis was annotated as a PFK based upon genomic analysis, its catalytic properties have to be examined experimentally. The cells of T. tengcongenisis were cultured at optimal temperature followed by the separation of the bacterial proteins with two-dimensional electrophoresis (2-DE). These 2-DE spots located around the theoretical values of pI and MW for TTE1816 were picked up and identified by mass spectrometry, suggesting that TTE1816 indeed expressed at such high temperature. Furthermore, TTE1816 was cloned into an expression vector and expressed soluble protein in E. coli BL-21 strain. The kinetic data revealed that the recombinant TTE1816 exhibited the catalysis to phosphorylate fructose-6-phosphate (F-6-P). Not only converting F-6-P to F-1,6-BP, does TTE1816 also catalyze the phosphorylation of glucose, fructose, mannose and glucose-6-phosphate(G-6-P) with optimal temperature at 60 degrees C . Interestingly, TTE1816 is capable to catalyze the reverse reaction as a bisphosphatase for dephosphorylation of F-1,6-BP under the reaction conditions with high concentrations of enzyme as well as substrates. The data reported herein demonstrate that a new member of PFK family has been identified in T. tengcongenisis.
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Affiliation(s)
- Chuan-Qi Zhou
- Beijing Genomics Institute, Chinese Academy of Sciences, Beijing 101318, China.
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13
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Marinho-Carvalho MM, Zancan P, Sola-Penna M. Modulation of 6-phosphofructo-1-kinase oligomeric equilibrium by calmodulin: formation of active dimers. Mol Genet Metab 2006; 87:253-61. [PMID: 16377227 DOI: 10.1016/j.ymgme.2005.11.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 11/04/2005] [Accepted: 11/08/2005] [Indexed: 01/04/2023]
Abstract
Muscle 6-phospho-1-kinase (PFK) is the key regulatory enzyme of the glycolytic pathway and is a calmodulin-binding protein binding two calmodulin molecules per PFK protomer. This enzyme is characterized by a complex regulation that involves its allosteric behavior modulated by several ligands, which modulate the equilibrium between the active tetramers and the inactive dimers of the enzyme. Calmodulin is described to induce the dimerization of PFK, so inhibiting its catalytic activity. Here, we show that binding of calmodulin specifically to its higher-affinity site of PFK induce its dimerization without compromising enzyme catalytic activity forming a hitherto not described active dimmer of PFK. It is also shown that the dimerization is a Ca2+ -dependent event that responds to physiological intracellular Ca2+ concentrations and decrease the interaction of the enzyme to membrane site, which stimulate its catalytic activity. We propose that the effects of calmodulin on PFK reported here are of great physiological significance due to the response to physiological concentrations of Ca2+ and due to be in accordance to the known effects of calmodulin on cell ATP production. We also propose that calmodulin might affect the interaction of PFK to other cellular components as the cytoskeleton.
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Affiliation(s)
- Monica M Marinho-Carvalho
- Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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14
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Abstract
DMSO is the standard solvent for preparing stock solutions of compounds for drug discovery. The assay concentration of DMSO is normally 0.1% to 5% (v/v) or 14 to 715 mM. Thus, DMSO is often one of the principal additives in assay buffers. This standardization of stock solutions does not eliminate possible pitfalls associated with the effects of the DMSO-containing solutions on individual proteins. In this article, the authors want to emphasize the importance of detailed studies of these effects in the early stages of drug discovery. Two protein systems, the extracellular soluble domain of the human growth hormone receptor (hGHbp) and the phosphatase domain of PFKFB1 (BPase), were used for the study on effects of DMSO on protein stability, protein aggregation, and binding of drug compounds. The study revealed significant differences in the proteins’ behavior in the presence and absence of low amounts of DMSO. The addition of DMSO resulted in destabilization of the proteins investigated and also changed the apparent binding property of 1 protein. The authors have also shown that low DMSO concentrations influence the ionization process in electrospray ionization mass spectrometry (ESI-MS).
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Kulkarni G, Sabnis NA, Bhat KS, Harris BG. CLONING AND NUCLEOTIDE SEQUENCE OF A FULL-LENGTH cDNA ENCODING ASCARIS SUUM PHOSPHOFRUCTOKINASE. J Parasitol 2005; 91:585-90. [PMID: 16108551 DOI: 10.1645/ge-369r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The nucleotide sequence of a full-length cDNA encoding phosphofructokinase (PFK) enzyme from the parasitic nematode Ascaris suum was determined. The entire sequence of 2,653 bases comprises a single open reading frame of 2,452 bases and a noncoding region of 201 bases after the stop codon. The mature protein contains 812 amino acids and has a molecular mass of 90,900 Da. The amino acid sequences of several peptides derived from the purified protein show excellent correspondence with the translated nucleotide sequence. Comparison of the amino acid sequence of the protein with those of 3 other worms as well as those of human, rabbit, and bacterial enzymes reveals highly conserved regions interrupted with stretches of lesser sequence similarity. Analyses of the subunit primary structure reveal, as in other eukaryotic PFKs, that the amino-terminal half is homologous to the carboxy-terminal half, supporting the hypothesis that the PFK gene evolved by duplication of the prokaryotic gene and that the allosteric sites arose by mutations at the catalytic site. The location of the phosphorylation site is unique and different compared with other PFKs and plays a key role in regulation of the enzyme activity. Structural motifs such as the putative substrate and effector binding domains and also the key amino acids involved therein are clearly identified by alignment of all the PFK protein sequences.
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Affiliation(s)
- Gopal Kulkarni
- Department of Molecular Biology and Immunology, University of North Texas, Health Science Center, Fort Worth, Texas 76107, USA
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Mesojednik S, Legisa M. Posttranslational modification of 6-phosphofructo-1-kinase in Aspergillus niger. Appl Environ Microbiol 2005; 71:1425-32. [PMID: 15746345 PMCID: PMC1065176 DOI: 10.1128/aem.71.3.1425-1432.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Accepted: 10/05/2004] [Indexed: 11/20/2022] Open
Abstract
Two different enzymes exhibiting 6-phosphofructo-1-kinase (PFK1) activity were isolated from the mycelium of Aspergillus niger: the native enzyme with a molecular mass of 85 kDa, which corresponded to the calculated molecular mass of the deduced amino acid sequence of the A. niger pfkA gene, and a shorter protein of approximately 49 kDa. A fragment of identical size also was obtained in vitro by the proteolytic digestion of the partially purified native PFK1 with proteinase K. When PFK1 activity was measured during the proteolytic degradation of the native protein, it was found to be lost after 1 h of incubation, but it was reestablished after induction of phosphorylation by adding the catalytic subunit of cyclic AMP-dependent protein kinase to the system. By determining kinetic parameters, different ratios of activities measured at ATP concentrations of 0.1 and 1 mM were detected with fragmented PFK1, as with the native enzyme. Fructose-2,6-biphosphate significantly increased the Vmax of the fragmented protein, while it had virtually no effect on the native protein. The native enzyme could be purified only from the early stages of growth on a minimal medium, while the 49-kDa fragment appeared later and was activated at the time of a sudden change in the growth rate. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of sequential purifications of PFK1 enzymes by affinity chromatography during the early stages of the fungal development suggested spontaneous posttranslational modification of the native PFK1 in A. niger cells, while from the kinetic parameters determined for both isolated forms it could be concluded that the fragmented enzyme might be more efficient under physiological conditions.
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Affiliation(s)
- Suzana Mesojednik
- National Institute of Chemistry, Hajdrihova 19, PO Box 660, Si-1001 Ljubljana, Slovenia
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Fenton AW, Paricharttanakul NM, Reinhart GD. Disentangling the web of allosteric communication in a homotetramer: heterotropic activation in phosphofructokinase from Escherichia coli. Biochemistry 2005; 43:14104-10. [PMID: 15518560 DOI: 10.1021/bi048569q] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phosphofructokinase from Escherichia coli (EcPFK) is a homotetramer with four active sites and four allosteric sites. Understanding the allosteric activation of EcPFK by MgADP has been complicated by the complex web of possible interactions, including active site homotropic interactions, allosteric site homotropic interactions, and heterotropic interactions between active and allosteric sites. The current work has simplified this web of possible interactions to a series of single heterotropic interactions by forming and isolating hybrid tetramers. Each of the four unique heterotropic interactions have independently been isolated and compared to a control that has all four of the unique heterotropic interactions. If the interactions are labeled with the distances between interacting ligands, the 45-A interaction contributes 20% +/- 1%, the 33-A interaction contributes 34% +/- 1%, the 30-A interaction contributes 21% +/- 1%, and the 23-A interaction contributes 25% +/- 1% with respect to the total free energy of MgADP/fructose 6-phosphate (Fru-6-P) activation in the control. The free energies of the isolated interactions sum to 100% +/- 2% of the total. Therefore, the four unique interactions are all contributors to activation, are nonequivalent, and are additive.
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Affiliation(s)
- Aron W Fenton
- Department of Biochemistry and Biophysics and the Center for Advanced Biomolecular Research, Texas A&M University, College Station, Texas 77843-2128, USA
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Garavaglia S, Raffaelli N, Finaurini L, Magni G, Rizzi M. A novel fold revealed by Mycobacterium tuberculosis NAD kinase, a key allosteric enzyme in NADP biosynthesis. J Biol Chem 2004; 279:40980-6. [PMID: 15269221 DOI: 10.1074/jbc.m406586200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NAD kinase catalyzes the magnesium-dependent phosphorylation of NAD, representing the sole source of freshly synthesized NADP in all organisms. The enzyme is essential for the growth of the deadly multidrug-resistant pathogen Mycobacterium tuberculosis and is an attractive target for novel antitubercular agents. The crystal structure of NAD kinase has been solved by multiwavelength anomalous dispersion at a resolution of 2.3 A in its T state. Two crystal forms have been obtained revealing either a dimer or a tetramer. The enzyme architecture discloses a novel molecular arrangement, with each subunit consisting of an alpha/beta N-terminal domain and a C-terminal 12-stranded beta sandwich domain, connected by swapped beta strands. The C-terminal domain shows a striking internal approximate 222 symmetry and an unprecedented topology, revealing a novel fold within the family of all beta structures. The catalytic site is located in the long crevice that defines the interface between the domains. The conserved GGDG structural fingerprint of the catalytic site is reminiscent of the related region in 6-phosphofructokinase, supporting the hypothesis that NAD kinase belongs to a newly reported superfamily of kinases.
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Affiliation(s)
- Silvia Garavaglia
- Dipartimento di Scienze Chimiche, Alimentari, Farmaceutiche, Farmacologiche-Istituto Nazionale Fisica della Materia, University of Piemonte Orientale "Amedeo Avogadro," Via Bovio 6, 28100 Novara, Italy
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Ortigosa AD, Kimmel JL, Reinhart GD. Disentangling the Web of Allosteric Communication in a Homotetramer: Heterotropic Inhibition of Phosphofructokinase from Bacillus stearothermophilus. Biochemistry 2003; 43:577-86. [PMID: 14717614 DOI: 10.1021/bi035077p] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A strategy for isolating each of the four potentially unique heterotropic pairwise allosteric interactions that exist in the homotetramer phosphofructokinase from Bacillus stearothermophilus is described. The strategy involves the construction of hybrid tetramers containing one wild-type subunit and three mutant subunits that have been modified to block binding of both the substrate, fructose 6-phosphate (Fru-6-P), and the allosteric inhibitor, phospho(enol)pyruvate (PEP). Each type of binding site occurs at a subunit interface, and mutations on either side of the interface have been identified that will greatly diminish binding at the respective site. Consequently, four different types of mutant subunits have been created, each containing a different active site and allosteric site modification. The corresponding 1:3 hybrids isolate a different pair of unmodified substrate and allosteric sites with a unique structural disposition located 22, 30, 32, and 45 A apart, respectively. The allosteric inhibition exhibited by the unmodified sites in each of these four hybrids has been quantitatively evaluated in terms of a coupling free energy. Each of the coupling free energies is unique in magnitude, and their relative magnitudes vary with pH. Importantly, the sum of these coupling free energies at each pH is equal to the total heterotropic coupling free energy associated with the tetrameric enzyme. The latter quantity was assessed from the overall inhibition of a control hybrid that removed the homotropic interactions in PEP binding. The results do not agree with either the concerted or sequential models that are often invoked to explain allosteric behavior in oligomeric enzymes.
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Affiliation(s)
- Allison D Ortigosa
- Department of Biochemistry and Biophysics and Center for Advanced Biomolecular Research, Texas A&M University, College Station, Texas 77843-2128, USA
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Ito S, Fushinobu S, Jeong JJ, Yoshioka I, Koga S, Shoun H, Wakagi T. Crystal structure of an ADP-dependent glucokinase from Pyrococcus furiosus: implications for a sugar-induced conformational change in ADP-dependent kinase. J Mol Biol 2003; 331:871-83. [PMID: 12909015 DOI: 10.1016/s0022-2836(03)00792-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
ADP-dependent kinases are used in the modified Embden-Meyerhoff pathway of certain archaea. Our previous study has revealed a mechanism for ADP-dependent phosphoryl transfer by Thermococcus litoralis glucokinase (tlGK), and its evolutionary relationship with ATP-dependent ribokinases and adenosine kinases (PFKB carbohydrate kinase family members). Here, we report the crystal structure of glucokinase from Pyrococcus furiosus (pfGK) in a closed conformation complexed with glucose and AMP at 1.9A resolution. In comparison with the tlGK structure, the pfGK structure shows significant conformational changes in the small domain and a region around the hinge, suggesting glucose-induced domain closing. A part of the large domain next to the hinge is also shifted accompanied with domain closing. In the pfGK structure, glucose binds in a groove between the large and small domains, and the electron density of O1 atoms for both the alpha and beta-anomer configurations was observed. The structural details of the sugar-binding site of ADP-dependent glucokinase were firstly clarified and then site-directed mutagenesis analysis clarified the catalytic residues for ADP-dependent kinase, such as Arg205 and Asp451 of tlGK. Homology search and multiple alignment of amino acid sequences using the information obtained from the structures reveals that eucaryotic hypothetical proteins homologous to ADP-dependent kinases retain the residues for the recognition of a glucose substrate.
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Affiliation(s)
- Sohei Ito
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Ruiz T, Mechin I, Bär J, Rypniewski W, Kopperschläger G, Radermacher M. The 10.8-A structure of Saccharomyces cerevisiae phosphofructokinase determined by cryoelectron microscopy: localization of the putative fructose 6-phosphate binding sites. J Struct Biol 2003; 143:124-34. [PMID: 12972349 DOI: 10.1016/s1047-8477(03)00140-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Phosphofructokinase plays a key role in the regulation of the glycolytic pathway and is responsible for the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate. Although the structure of the bacterial enzyme is well understood, the knowledge is still quite limited for higher organisms given the larger size and complexity of the eukaryotic enzymes. We have studied phosphofructokinase from Saccharomyces cerevisiae in the presence of fructose 6-phosphate by cryoelectron microscopy and image analysis of single particles and obtained the structure at 10.8A resolution. This was achieved by optimizing the illumination conditions to obtain routinely 8-A data from hydrated samples in an electron microscope equipped with an LaB(6) and by improving the image alignment techniques. The analysis of the structure has evidenced that the homology of the subunits at the sequence level has transcended to the structural level. By fitting the X-ray structure of the bacterial tetramer into each dimer of the yeast octamer the putative binding sites for fructose 6-phosphate were revealed. The data presented here in combination with molecular replacement techniques have served to provide the initial phases to solve the X-ray structure of the yeast phosphofructokinase.
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Affiliation(s)
- Teresa Ruiz
- Department of Molecular Physiology and Biophysics, University of Vermont College of Medicine, Burlington, VT 05405, USA.
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22
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Tian KL, Lin JQ, Liu XM, Liu Y, Zhang CK, Yan WM. Conversion of an obligate autotrophic bacteria to heterotrophic growth: expression of a heterogeneous phosphofructokinase gene in the chemolithotroph Acidithiobacillus thiooxidans. Biotechnol Lett 2003; 25:749-54. [PMID: 12882002 DOI: 10.1023/a:1023588921918] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A plasmid pSDK-1 containing the Escherichia coli phosphofructokinase-1 gene (pfkA) was constructed, and transferred into Acidithiobacillus thiooxidans Tt-7 by conjugation. The pfkA gene from E. coli could be expressed in this obligately autotrophic bacterium but the enzyme activity (18 U g-1) was lower than that in E. coli (K12: 86 U g-1; DF1010 carrying plasmid pSDK-1: 97 U g-1). In the presence of glucose, the Tt-7 transconjugant consumed glucose leading to a better growth yield.
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Affiliation(s)
- Ke Li Tian
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, P.R. China.
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Abstract
In this paper, we report evidences that cellular distribution of phosphofructokinase can be affected by epinephrine stimulation in rabbit skeletal muscle homogenates. Through co-sedimentation techniques, we observed that in epinephrine-stimulated tissues, approximately 50% of phosphofructokinase activity is co-located in an actin-enriched fraction, against 29% in control. This phenomenon is accompanied by a 400% increase in specific phosphofructokinase activity in stimulated homogenates. This effect is reproduced by the beta-adrenergic agonist isoprenaline. Here we propose that the modulation of cellular distribution of phosphofructokinase may be one of the mechanisms of control of glycolytic flux in mammalian muscle, by beta-adrenergic stimulation.
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Affiliation(s)
- Gutemberg Gomes Alves
- Laboratório de Enzimologia e Controle do Metabolismo (LabECoM), Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Abstract
Escherichia coli phosphofructokinase 1 (EcPFK) is a homotetramer with four active and four allosteric sites. Understanding of the structural basis of allosteric activation of EcPFK by MgADP is complicated by the multiplicity of binding sites. To isolate a single heterotropic allosteric interaction, hybrid tetramers were formed between wild-type and mutant EcPFK subunits in which the binding sites of the mutant subunits have decreased affinity for their respective ligands. The 1:3 (wild-type:mutant) hybrid that contained only one native active site and one native allosteric site was isolated. The affinity for the substrate fructose-6-phosphate (Fru-6-P) of a single wild-type active site is greatly decreased over that displayed by the wild-type tetramer due to the lack of homotropic activation. The free energy of activation by MgADP for this heterotropic interaction is -0.58 kcal/mol at 8.5 degrees C. This compares to -2.87 kcal/mol for a hybrid with no homotropic coupling but all four unique heterotropic interactions. Therefore, the isolated interaction contributes 20% of the total heterotropic coupling. By comparison, wild-type EcPFK exhibits a coupling free energy between Fru-6-P and MgADP of -1.56 kcal/mol under these conditions, indicating that the effects of MgADP are diminished by a homotropic activation equal to -1.3 kcal/mol. These data are not consistent with a concerted allosteric mechanism.
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Affiliation(s)
- Aron W Fenton
- Department of Biochemistry and Biophysics and the Center for Advanced Biomolecular Research, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, USA
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Riley-Lovingshimer MR, Ronning DR, Sacchettini JC, Reinhart GD. Reversible ligand-induced dissociation of a tryptophan-shift mutant of phosphofructokinase from Bacillus stearothermophilus. Biochemistry 2002; 41:12967-74. [PMID: 12390023 DOI: 10.1021/bi0263412] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The biophysical properties of a tryptophan-shifted mutant of phosphofructokinase from Bacillus stearothermophilus (BsPFK) have been examined. The mutant, designated W179Y/Y164W, has kinetic and thermodynamic properties similar to the wild-type enzyme. A 2-fold decrease in kcat is observed, and the mutant displays a 3-fold smaller K(0.5) for the substrate, fructose-6-phosphate (Fru-6-P), as compared to the wild-type enzyme. The dissociation constant for the inhibitor, phospho(enol)pyruvate (PEP), increases 2-fold, and the coupling parameter, Q(ay), decreases 2-fold. This suggests that while the mutant displays a slightly decreased affinity for PEP, PEP is still an effective inhibitor once bound. The new position of the tryptophan in W179Y/Y164W is approximately 6 A from the Fru-6-P portion of the active site. A 25% decrease in fluorescence intensity is observed upon Fru-6-P binding, and an 80% decrease in fluorescence intensity is observed with PEP binding. In addition, the intrinsic fluorescence polarization increases from 0.327 +/- 0.001 to 0.353 +/- 0.001 upon Fru-6-P binding, but decreases to 0.290 +/- 0.001 when PEP binds. Most notably, the presence of PEP induces dissociation of the tetramer. Dissociation of the tetramer into dimers occurs along the active site interface and can be monitored by the loss in activity or the loss in tryptophan fluorescence that is observed when the enzyme is titrated with PEP. Activity can be protected or recovered by incubating the enzyme with Fru-6-P. Recovery of activity is enzyme concentration dependent, and the rate constant for association is 6.2 +/- 0.3 M(-1) x s(-1). Ultracentrifugation experiments revealed that in the absence of PEP the mutant enzyme exists in an equilibrium between the dimer and tetramer forms with a dissociation constant of 11.8 +/- 0.5 microM, while in the presence of PEP the enzyme exists in equilibrium between the dimer and monomer forms with a dissociation constant of 7.5 +/- 0.02 microM. A 3.1 A crystal structure of the mutant enzyme suggests that the amino acid substitutions have not dramatically altered the tertiary structure of the enzyme. While it is clear that wild-type BsPFK exists as a tetramer under these same conditions, these results suggest that quaternary structural changes probably play an important role in allosteric communication.
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Affiliation(s)
- Michelle R Riley-Lovingshimer
- Department of Biochemistry and Biophysics and Center for Advanced Biomolecular Research, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, USA
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Claustre S, Denier C, Lakhdar-Ghazal F, Lougare A, Lopez C, Chevalier N, Michels PAM, Périé J, Willson M. Exploring the active site of Trypanosoma brucei phosphofructokinase by inhibition studies: specific irreversible inhibition. Biochemistry 2002; 41:10183-93. [PMID: 12162732 DOI: 10.1021/bi020082z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work deals with the phosphofructokinase enzyme (PFK) of the parasite Trypanosoma brucei. Inhibitors which are analogues of fructose-6-phosphate (F6P) derived from 2,5-anhydromannitol and therefore blocked in a closed conformation, both nonphosphorylated and phosphorylated, were designed. They provided information on this class of ATP-dependent PFK (structurally more similar to PPi-dependent PFKs revealing (i) an ordered mechanism, ATP binding first, inducing an essential conformational change to increase the affinity for F6P, and (ii) a rather hydrophobic environment at the ATP binding site. Nonphosphorylated mannitol derivatives bind at both the ATP and F6P binding sites, whereas the phosphorylated derivatives only bind at the ATP binding site. The inhibitors bearing an aromatic ring substituted at the meta position indicate a polar interaction with lysine 227, which is specific to T. brucei PFK and is replaced by a glycine in human PFK. This lysine can be irreversibly bound, leading to inhibition when an electrophilic carbon atom is beta to the meta position on the ring. This lysine was identified by site-directed mutagenesis. This first example of a specific irreversible inactivation of T. brucei PFK offers an opportunity to develop biologically active compounds against the sleeping sickness, the causative agent of which is the trypanosome.
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Affiliation(s)
- Samantha Claustre
- Laboratoire Synthèse et Physico Chimie de Molécules d'Intérêt Biologique UMR-CNRS 5068, Universitè Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex, France
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Kirchberger J, Bär J, Schellenberger W, Dihazi H, Kopperschläger G. 6-phosphofructokinase from Pichia pastoris: purification, kinetic and molecular characterization of the enzyme. Yeast 2002; 19:933-47. [PMID: 12125050 DOI: 10.1002/yea.885] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
6-Phosphofructokinase from Pichia pastoris was purified for the first time to homogeneity applying seven steps, including pseudo-affinity dye-ligand chromatography on Procion Blue H-5R-Sepharose. The specific activity of the purified enzyme was about 80 U/mg. It behaves as a typically allosteric 6-phosphofructokinase exhibiting activation by AMP and fructose 2,6-bis(phosphate), inhibition by ATP and cooperativity to fructose 6-phosphate. However, in comparison with the enzymes from Saccharomyces cerevisiae and Kluyveromyces lactis, the activation ratio of 6-phosphofructokinase from Pichia pastoris by AMP is several times higher, the ATP inhibition is stronger and the apparent affinity to fructose 6-phosphate is significantly lower. Aqueous two-phase affinity partitioning with Cibacron Blue F3G-A did not reflect remarkable structural differences of the nucleotide binding sites of the Pfks from Pichia pastoris and Saccharomyces cerevisiae. The structural organisation of the active enzyme seems to be different in comparison with hetero-octameric 6-phosphofructokinases from other yeast species. The enzyme was found to be a hetero-oligomer with an molecular mass of 975 kDa (sedimentation equilibrium measurements) consisting of two distinct types of subunits in an equimolar ratio with molecular masses of 113 kDa and 98 kDa (SDS-PAGE), respectively, and a third non-covalently complexed protein component (34 kDa, SDS-PAGE). The latter seems to be necessary for the catalytic activity of the enzyme. Sequencing of the N-terminus (VTKDSIXRDLEXENXGXXFF) and of peptide fragments by applying MALDI-TOF PSD, m/z 1517.3 (DAMNVVNH) and m/z 2177.2 [AQNCNVC(L/I)SVHEAHTM] gave no relevant information about the identity of this protein.
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Affiliation(s)
- Jürgen Kirchberger
- Institut für Biochemie, Medizinische Fakultät der Universität Leipzig, Liebigstrasse 16, D-04103 Leipzig, Germany.
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Abstract
Previously, studies on glucose-induced microautophagy in the methylotrophic yeast Pichia pastoris provided evidence that the glucose-induced selective autophagy-1-protein is the alpha-subunit of 6-phosphofructokinase (Pfk), a key enzyme in the glycolytic pathway. In our work, we could clearly demonstrate that two types of subunits of Pfk exist in P. pastoris. Investigating the yeast cell-free extract by Western blot analysis, two distinct signals of Pfk were obtained. In addition, we isolated a DNA sequence containing the complete ORF of PpPFK2 encoding the beta-subunit of Pfk from P. pastoris with a deduced molecular mass of 103.7 kDa. On the basis of these results, a hetero-oligomeric structure of Pfk in P. pastoris became obvious. Because the molecular and kinetic properties of a homo-oligomeric yeast Pfk appear to be more similar to those of mammalian Pfk, as described in the literature, our results are of interest for the growing number of studies on P. pastoris as a heterologous production system. Furthermore, the 3'- and 5'-non-coding regions of PpPFK2 were isolated and several putative binding sites for regulatory factors could be identified in the promoter region.
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Affiliation(s)
- Anke Edelmann
- Institute of Biochemistry, Medical Faculty, University of Leipzig, Liebigstrasse 16, 04103 Leipzig, Germany.
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López C, Chevalier N, Hannaert V, Rigden DJ, Michels PAM, Ramirez JL. Leishmania donovani phosphofructokinase. Gene characterization, biochemical properties and structure-modeling studies. Eur J Biochem 2002; 269:3978-89. [PMID: 12180974 DOI: 10.1046/j.1432-1033.2002.03086.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The characterization of the gene encoding Leishmania donovani phosphofructokinase (PFK) and the biochemical properties of the expressed enzyme are reported. L. donovani has a single PFK gene copy per haploid genome that encodes a polypeptide with a deduced molecular mass of 53 988 and a pI of 9.26. The predicted amino acid sequence contains a C-terminal tripeptide that conforms to an established signal for glycosome targeting. L. donovani PFK showed most sequence similarity to inorganic pyrophosphate (PPi)-dependent PFKs, despite being ATP-dependent. It thereby resembles PFKs from other Kinetoplastida such as Trypanosoma brucei, Trypanoplasma borreli (characterized in this study), and a PFK found in Entamoeba histolytica. It exhibited hyperbolic kinetics with respect to ATP whereas the binding of the other substrate, fructose 6-phosphate, showed slight positive cooperativity. PPi, even at high concentrations, did not have any effect. AMP acted as an activator of PFK, shifting its kinetics for fructose 6-phosphate from slightly sigmoid to hyperbolic, and increasing considerably the affinity for this substrate, whereas GDP did not have any effect. Modelling studies and site-directed mutagenesis were employed to shed light on the structural basis for the AMP effector specificity and on ATP/PPi specificity among PFKs.
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Affiliation(s)
- Claudia López
- Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, Venezuela
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Abstract
Mammalian phosphofructokinase (PFK) has evolved by a process of tandem gene duplication and fusion to yield a protein that is more than double the size of prokaryotic PFKs. On the basis of complete conservation of active site residues in the N-terminal half of the eukaryotic enzyme with those of the bacterial PFKs, one assumes that the active site of the eukaryotic PFK is located in the N-terminal half. Again using sequence comparisons, the four allosteric ligand sites of mammalian PFK have been thought to arise from the duplicated catalytic and regulatory sites of the ancestral PFK. Previous site-directed mutagenesis studies [Li et al. (1999) Biochemistry 38, 16407-16412; Chang and Kemp (2002) Biochem. Biophys. Res. Commun. 290, 670-675] have identified the origins of the citrate and fructose 2,6-bisphosphate sites. Here, site-directed mutagenesis of two arginine residues (Arg-433 and Arg-429) of mouse phosphofructokinase is used to identify the ATP inhibitory site, and, by inference, the AMP/ADP site. Mutation of the residues to alanine reduced ATP inhibition in the case of Arg-429 and eliminated ATP inhibition in the instance of Arg-433. The Arg-433 mutant could be inhibited by citrate, and that inhibition could be reversed by fructose 2,6-bisphosphate and cyclic AMP, a high-affinity ligand for the AMP/ADP binding site. It is concluded that the two inhibitors, ATP and citrate, of mammalian PFK interact with sites that have evolved from the duplicated phosphoenolpyruvate/ADP allosteric site of the ancestral PFK. The two sites for activators, fructose 2,6-bisphosphate and AMP or ADP, have evolved from the catalytic site of the ancestral precursor.
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Affiliation(s)
- Robert G Kemp
- Department of Biochemistry and Molecular Biology, The Chicago Medical School, North Chicago, Illinois 60064, USA.
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Edelmann A, Kirchberger J, Heinisch JJ, Kopperschläger G. C-terminal modification of 6-phosphofructo-1-kinase from Saccharomyces cerevisiae and its influence on enzyme structure and activity. Biochem Biophys Res Commun 2002; 295:992-9. [PMID: 12127994 DOI: 10.1016/s0006-291x(02)00773-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Studies on limited proteolysis of 6-phosphofructo-1-kinase (Pfk-1) from Saccharomyces cerevisiae led to the suggestion that the C-terminal part of the alpha-subunit must contribute to the stabilisation of the octameric enzyme structure. To analyse the role of the C-terminus in vivo, the respective terminus of one of both types of subunits of Pfk-1 was sequentially truncated or extended. These modifications resulted in a decrease of the protein level of the mutated subunit and of the specific enzyme activity in the cell-free extract as well as in changes of the kinetic properties. Size exclusion HPLC demonstrated that the modified subunit is still able to assemble with the native counterpart generating an enzymatically active hetero-octamer. On the basis of our results we assume that the C-termini are important for the three-dimensional structure of the subunits determining their susceptibility to proteolysis and the ability to assembly to an active, oligomeric Pfk-1.
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Affiliation(s)
- Anke Edelmann
- Institut für Biochemie der Medizinischen Fakultät, Universität Leipzig, Liebigstrasse 16, Leipzig, Germany.
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Labesse G, Douguet D, Assairi L, Gilles AM. Diacylglyceride kinases, sphingosine kinases and NAD kinases: distant relatives of 6-phosphofructokinases. Trends Biochem Sci 2002; 27:273-5. [PMID: 12069781 DOI: 10.1016/s0968-0004(02)02093-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Diacylglyceride kinases, sphingosine kinases, NAD kinases and 6-phosphofructokinases are thought to be related despite large evolution of their sequences. Discovery of a common signature has led to the suggestion that they possess a similar phosphate-donor-binding site and a similar phosphorylation mechanism. The substrate- and allosteric-binding sites are much more divergent and their delineation remains to be determined experimentally.
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Affiliation(s)
- Gilles Labesse
- Centre de Biochimie Structurale, INSERM U554-CNRS UMR5048, Universite Montpellier I, 15 Avenue Charles Flahault, 34060 Montpellier Cedex, France.
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Hansen T, Musfeldt M, Schönheit P. ATP-dependent 6-phosphofructokinase from the hyperthermophilic bacterium Thermotoga maritima: characterization of an extremely thermophilic, allosterically regulated enzyme. Arch Microbiol 2002; 177:401-9. [PMID: 11976749 DOI: 10.1007/s00203-002-0405-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2001] [Revised: 01/22/2002] [Accepted: 01/25/2002] [Indexed: 10/27/2022]
Abstract
The ATP-dependent 6-phosphofructokinase (ATP-PFK) of the hyperthermophilic bacterium Thermotoga maritimawas purified 730-fold to homogeneity. The enzyme is a 140-kDa homotetramer composed of 34 kDa subunits. Kinetic constants were determined for all substrates in both reaction directions at pH 7 and at 75 degrees C. Rate dependence (forward reaction) on fructose 6-phosphate (F-6-P) showed sigmoidal kinetics with a half-maximal saturation constant ( S(0.5)) of 0.7 mM and a Hill coefficient of 2.2. The apparent K(m) for ATP was 0.2 mM and the apparent V(max) value was about 360 U/mg. The enzyme also catalyzed in vitro the reverse reaction with an apparent K(m) for fructose 1,6-bisphosphate and ADP of 7.6 mM and 1.4 mM, respectively, and an apparent V(max) of about 13 U/mg. Divalent cations were required for maximal activity; Mg(2+), which was most effective, could partially be replaced by Mn(2+) and Fe(2+). Enzyme activity was allosterically regulated by classical effectors of ATP-PFKs of Eukarya and Bacteria; it was activated by ADP and inhibited by PEP. The enzyme had a temperature optimum of 93 degrees C and showed a significant thermostability up to 100 degrees C. Using the N-terminal amino acid sequence of the subunit, the pfk gene coding for ATP-PFK was identified and functionally overexpressed in Escherichia coli. The purified recombinant ATP-PFK had identical kinetic and allosteric properties as the native enzyme purified from T. maritima. The deduced amino acid sequence showed high sequence similarity to members of the PFK-A family. In accordance with its allosteric properties, ATP-PFK of T. maritima contained the conserved allosteric effector-binding sites for ADP and PEP.
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Affiliation(s)
- Thomas Hansen
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
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Ruiz T, Kopperschläger G, Radermacher M. The first three-dimensional structure of phosphofructokinase from Saccharomyces cerevisiae determined by electron microscopy of single particles. J Struct Biol 2001; 136:167-80. [PMID: 12051897 DOI: 10.1006/jsbi.2002.4440] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phosphofructokinaseis a key regulatory enzyme of the glycolytic pathway. We have determined the structure of this enzyme from Saccharomyces cerevisiae to a resolution of 2.0 nm. This is the first structure available for this family of enzymes in eukaryotic organisms. Phosphofructokinase is an octamer composed of 4alpha and 4beta subunits arranged in a dihedral point group symmetry D(2). The enzyme has a very open and elongated structure, with dimensions of 24 nm in length and 17 nm in width. The final structure, calculated from 0 degrees tilt projections of the molecule at random orientations using as reference the volume obtained by the random conical reconstruction technique in ice, has allowed us to discern the shapes of the subunits and their mutual arrangement in the octamer.
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Affiliation(s)
- T Ruiz
- Abt. Strukturbiologie, Max-Planck-Institut für Biophysik, Heinrich Hoffmann Str. 7, Frankfurt/M., D-60528, Germany.
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Abstract
To assess the role of quaternary stability on the properties of Escherichia coli phosphofructokinase (PFK), a disulfide bond has been introduced across the subunit interface containing the allosteric binding sites in E. coli phosphofructokinase by changing N288 to cysteine. N288 is located in close proximity to the equivalent residue on an adjacent subunit. Although SDS-PAGE of oxidized N288C indicates monomeric protein, blocking the six native cysteine residues with N-ethyl maleimide (NEM) reveals dimers of N288C on non-native gels. Subsequent addition of dithiothreitol (DTT) to NEM-labeled N288C regenerates the monomer on SDS-PAGE, reflecting the reversibility of intersubunit disulfide bond formation. KSCN-induced hybrid formation between N288C and the charged-tagged mutant E195,199K exhibits full monomer-monomer exchange only upon DTT addition, providing a novel assessment of disulfide bond formation without NEM treatment. N288C also exhibits a diminished tendency toward nonspecific aggregation under denaturing conditions, a phenomenon associated with monomer formation in PFK. Pressure-induced dissociation and urea denaturation studies further indicate that oxidized N288C exhibits increased quaternary stability along both interfaces of the tetramer, suggesting a synergistic relationship between active site and allosteric site formation. Although the apparent binding affinities of substrates and effectors change somewhat upon disulfide formation in N288C, little difference is evident between the maximally inhibited and activated forms of the enzyme in oxidizing versus reducing conditions. Allosteric influence, therefore, is not correlated to subunit-subunit affinity, and does not involve substantial interfacial rearrangement.
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Affiliation(s)
- J L Johnson
- Department of Chemistry, Southwestern Oklahoma State University, Weatherford, Oklahoma 73096, USA
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Abstract
Phosphofructokinase from Bacillus stearothermophilus (BsPFK) is a model allosteric enzyme system in which the interactions between substrates and allosteric effectors have been extensively studied. However, the oligomeric nature of BsPFK has made it difficult to determine the molecular basis of the allosteric regulation because of the multitude of different types of heterotropic and homotropic interactions that are possible between the four active sites and four allosteric sites in the native tetramer. In an attempt to alleviate the complexity of the system and thereby allow the quantitation of a single interaction between one active site and one allosteric site, site-directed mutagenesis has been coupled with a hybrid-forming scheme to create and isolate a tetramer of BsPFK in which only a single active site and a single allosteric site are capable of binding their respective ligands with high (i.e., near wild type) affinity. Characterization of this single allosteric interaction indicates that the free energy involved in the inhibition by the allosteric effector phosphoenolpyruvate (PEP) is 1.48 +/- 0.15 kcal/mol compared to the 3.58 +/- 0.02 kcal/mol measured for the enzyme.
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Affiliation(s)
- J L Kimmel
- Department of Biochemistry and Biophysics and Center for Advanced Biomolecular Research, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, USA
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Abstract
Stopped-flow kinetics was utilized to determine how allosteric activators and inhibitors of wild-type Escherichia coli phosphofructokinase influenced the kinetic rate and equilibrium constants of the binding of substrate fructose 6-phosphate. Monitoring pre-steady state fluorescence intensity emission changes upon an addition of a ligand to the enzyme was possible by a unique tryptophan per subunit of the enzyme. Binding of fructose 6-phosphate to the enzyme displayed a two-step process, with a fast complex formation step followed by a relatively slower isomerization step. Systematic addition of fructose 6-phosphate to phosphofructokinase in the absence and presence of several fixed concentrations of phosphoenolpyruvate indicated that the inhibitor binds to the enzyme concurrently with the substrate, forming a ternary complex and inducing a conformational change, rather than a displacement of the equilibrium as predicted by the classical two-state model (Monod, J., Wyman, J., and Changeux, J. P. (1965) J. Mol. Biol. 12, 88-118). The activator, MgADP, also altered the affinity of fructose 6-phosphate to the enzyme by forming a ternary complex. Furthermore, both phosphoenolpyruvate and MgADP act by influencing the fast complex formation step while leaving the slower enzyme isomerization step essentially unchanged.
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Affiliation(s)
- A S Pham
- Division of Pathology and Laboratory Medicine, the University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
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Zhu Z, Ling S, Yang QH, Li L. Involvement of the chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase sequence His444-Arg-Glu-Arg in modulation of the bisphosphatase activity by its kinase domain. Biochem J 2001; 357:513-20. [PMID: 11439102 PMCID: PMC1221979 DOI: 10.1042/0264-6021:3570513] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The bisphosphatase activity of the hepatic bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase is repressed by its kinase domain, and regulated by cAMP-dependent protein kinase (PKA)-catalysed phosphorylation. In the present study, the mechanism by which the bisphosphatase activity is repressed by the kinase domain and regulated by phosphorylation was investigated. We found that truncation of the C-terminus of the enzyme by 25, but not 20, amino acids dramatically enhanced the catalytic rate of the bisphosphatase, abrogated the inhibition by the kinase domain, and eliminated the effect of PKA-mediated phosphorylation on activity. In addition, mutation of His444-Arg-Glu-Arg to Ala-Ala-Glu-Ala had similar effects as the deletion. Moreover, the mutations also significantly affected the phosphorylation-mediated regulation of the kinase activity of the enzyme. Furthermore, the mutations altered the pH-dependence of the bisphosphatase, and the mutant bisphosphatases were more sensitive to modification by diethyl pyrocarbonate and guanidine-induced inactivation than the wild-type enzyme. Taken together, these results demonstrate that the sequence His444-Arg-Glu-Arg plays a critical role in repression of the bisphosphatase activity by both the N-terminal kinase domain and the C-terminal tail itself. These results also explain the activation of the bisphosphatase activity by PKA-catalysed phosphorylation, by suggesting that phosphorylation may relieve the inhibitory effect of the kinase domain that is mediated by the three basic residues in this sequence.
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Affiliation(s)
- Z Zhu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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Panserat S, Plagnes-Juan E, Kaushik S. Nutritional regulation and tissue specificity of gene expression for proteins involved in hepatic glucose metabolism in rainbow trout (Oncorhynchus mykiss). J Exp Biol 2001; 204:2351-60. [PMID: 11507117 DOI: 10.1242/jeb.204.13.2351] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Rainbow trout (Oncorhynchus mykiss) are known to use dietary carbohydrates poorly. One of the hypotheses to explain the poor utilisation of dietary glucose by these fish is a dysfunction in nutritional regulation of hepatic glucose metabolism. In this study, we obtained partial clones of rainbow trout cDNAs coding for a glucose transporter (Glut2), and for the enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (6PF-2K/F-2,6BPase), fructose-1,6-bisphosphatase (FBPase) and pyruvate kinase (PK). Their deduced amino acid sequences were highly similar to those of mammals (up to 80% similarity). In a study of nutritional regulation, the Glut2 gene was highly expressed in the liver irrespective of the nutritional status of the trout, in agreement with the role of this transporter in the input (during refeeding) and output (during fasting) of glucose from the liver. Moreover, whereas PK and FBPase gene expression was high irrespective of the nutritional status, levels of hepatic 6PF-2K/F-2,6BPase mRNA were higher in fish fed with carbohydrates than in fish deprived of food. The high levels of hepatic PK, Glut2 and 6PF-2K/F-2,6BPase gene expression observed in this study suggest a high potential for tissue carbohydrate utilisation in rainbow trout. The persistence of a high level of FBPase gene expression suggests an absence of regulation of the gluconeogenic pathway by dietary carbohydrates.
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Affiliation(s)
- S Panserat
- Laboratory of Fish Nutrition, INRA-IFREMER, 64310 St-Pée-sur-Nivelle, France.
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40
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Knoche M, Mönnich K, Schäfer HJ, Kopperschläger G. Photoaffinity labeling and photoaffinity cross-linking of phosphofructokinase-1 from Saccharomyces cerevisiae by 8-azidoadeninenucleotides. Arch Biochem Biophys 2001; 385:301-10. [PMID: 11368011 DOI: 10.1006/abbi.2000.2158] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phosphofructokinase-1 from Saccharomyces cerevisiae is composed of four alpha- and four beta-subunits, each of them carrying catalytic and regulatory bindings sites for MgATP. In this paper, various photoaffinity labels, such as 8-azidoadenosine 5'-triphosphate, 8-azido-1,N6-ethenoadenosine 5'-triphosphate, and 8-N3-3'(2')-O-biotinyl-8-azidoadenosine 5'-triphosphate have been used to study their interaction with the enzyme in the dark and during irradiation. All nucleotidetriphosphates function as phosphate donor forming fructose 1,6-bisphosphate from fructose 6-phosphate. However, the kinetic analysis revealed distinctly differences between them. Photolabeling causes a decrease in enzyme activity to a similar extent, and ATP acts as competitive effector to inactivation. Three bifunctional diazidodiadeninedinucleotides (8-diN3AP4A, monoepsilon-8-diN3AP4A, and diepsilon-8-diN3AP4A) were applied for studying the spatial arrangement of the nucleotide binding sites. No cross-linking of the subunits was obtained by irradiation of the enzyme with 8-diN3AP4A. Photolabeling with diepsilon-8-diN3AP4A resulted in the formation of two alpha-beta cross-links with different mobilities in the SDS-polyacrylamide gel electrophoresis, while monoepsilon-8-diN3AP4A yielded only one alpha-beta cross-link. Because an interfacial location of the catalytic sites between two subunits is less likely, we suggest that the formation of cross-linked subunits may be the result of specific interactions of the bifunctional photolabels with regulatory sites at the interface of both subunits.
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Affiliation(s)
- M Knoche
- Institut für Biochemie, Fachbereich Chemie und Pharmazie, Johannes Gutenberg-Universität Mainz, Germany
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41
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Abstract
During postnatal development of rat cochlear cells and the onset of hearing (10-23 days), the increasing endocochlear potential and energy requirements are largely provided by increased glucose utilization. It is well established that the ability of maturing rat tissues to use glucose is directly related to alteration of 6-phosphofructo-1-kinase (PFK) subunits. To gain insight into the alteration of PFK subunit levels in the cochlea from 6 to 60 days of age, PFK subunit types were measured in sections of paraffin-embedded temporal bone using IgG specific for each type of PFK subunit and quantified by computer image analysis. Although the L-type and C-type subunits did not exhibit statistically significant changes in the cochlear structures during maturation, the levels of M-type subunit in the stria vascularis cells, spiral ligament cell types I, II, and III, outer hair cells, inner hair cells, and support cells significantly increased. Also, the type IV and V spiral ligament fibrocytes during this period did not exhibit significant alterations of the M-type subunit. These data suggest that during neonatal development of the cochlear, the elevated levels of the M-type subunit are associated with increased glucose utilization and the onset of hearing.
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MESH Headings
- Animals
- Animals, Newborn
- Cochlea/cytology
- Cochlea/enzymology
- Cochlea/growth & development
- Energy Metabolism
- Glucose/metabolism
- Hair Cells, Auditory, Inner/cytology
- Hair Cells, Auditory, Inner/growth & development
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Outer/cytology
- Hair Cells, Auditory, Outer/growth & development
- Hair Cells, Auditory, Outer/metabolism
- Hearing/physiology
- Immunohistochemistry
- Phosphofructokinase-1/chemistry
- Phosphofructokinase-1/metabolism
- Protein Subunits
- Rats
- Rats, Inbred F344
- Stria Vascularis/cytology
- Stria Vascularis/metabolism
- Tissue Distribution
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Affiliation(s)
- G Armour
- Department of Pharmacology, Division of Otolaryngology, Southern Illinois University School of Medicine, Springfield 62794-9629, USA
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42
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Rodicio R, Strauss A, Heinisch JJ. Single point mutations in either gene encoding the subunits of the heterooctameric yeast phosphofructokinase abolish allosteric inhibition by ATP. J Biol Chem 2000; 275:40952-60. [PMID: 11221662 DOI: 10.1074/jbc.m007131200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Yeast phosphofructokinase is a heterooctameric enzyme subject to a complex allosteric regulation. A mutation in the PFK1 gene, encoding the larger -subunits, rendering the enzyme insensitive to allosteric inhibition by ATP was found to be caused by an exchange of proline 728 for a leucine residue. By in vitro mutagenesis, we introduced this mutation in either PFK1 or PFK2 and found that the exchange in either subunit drastically reduced the sensitivity of the holoenzyme to ATP inhibition. This was accompanied by a lack of allosteric activation by AMP, fructose 2,6-bisphosphate, or ammonium and an increased resistance to heat inactivation. Yeast cells carrying either one mutation or both in conjunction did not display a strong phenotype when grown on fermentable carbon sources and did not show any significant changes in intermediary metabolites. Growth on non-fermentable carbon sources was clearly impaired. The strain carrying both mutant alleles was more sensitive to Congo Red than the wild-type strain or the single mutants indicating differences in cell wall composition. In addition, we found single pfk null mutants to be less viable than wild type at different storage temperatures and a pfk2 null mutant to be temperature-sensitive for growth at 37 degrees C. The latter mutant was shown to be respiration-dependent for growth on glucose.
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Affiliation(s)
- R Rodicio
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Oviedo, Spain
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Urbano AM, Gillham H, Groner Y, Brindle KM. Effects of overexpression of the liver subunit of 6-phosphofructo-1-kinase on the metabolism of a cultured mammalian cell line. Biochem J 2000; 352 Pt 3:921-7. [PMID: 11104704 PMCID: PMC1221535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Overexpression of the liver subunit of 6-phosphofructo-1-kinase in Chinese hamster ovary K1 cells was shown to increase the steady-state level of the enzyme's product, fructose 1, 6-bisphosphate, and to produce a small but significant decrease in the concentration of fructose 2,6-bisphosphate, which is an allosteric activator of the enzyme. However, overexpression of the enzyme had no effect on glycolytic flux under a variety of different substrate conditions. This latter observation is consistent with similar studies in fungi and in potato tubers which indicate that 6-phosphofructo-1-kinase has very little control over flux in glycolysis.
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Affiliation(s)
- A M Urbano
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Old Addenbrook's Site, Cambridge CB2 1GA, U.K
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Mhaskar Y, Armour G, Dunaway G. Alteration of the levels of the M-type 6-phosphofructo-1-kinase mRNA isoforms during neonatal maturation of heart, brain and muscle. Mol Cell Biochem 2000; 214:81-7. [PMID: 11195794 DOI: 10.1023/a:1007195017569] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
During muscle, heart, and brain neonatal maturation, the capacity to utilize glucose in energy metabolism is directly related to the extent of accumulation of the 6-phosphofructo-1-kinase (PFK) M-type subunit. Neonatal development of other organs, such as liver and kidney, which are not characterized by large increases in the capacity to use glucose do not exhibit large increases in the M-type subunit protein. The presence of the M-type subunit in a PFK isozyme pool fosters a higher affinity utilization of carbohydrate and increased responsiveness to the levels of regulatory metabolites. To better appreciate this phenomenon, which is vital for normal development, the different isoforms of the M-type subunit mRNA's and alteration of their levels during maturation have been examined. Further, the potential promoter regions, i.e., the regions upstream from the sites of initiation of transcription, which are involved in expression of the different M-type subunit mRNA isoforms have been isolated, sequenced, and examined for possible transcription factor interaction sites. Using cDNA libraries produced from adult rat brain or skeletal muscle RNA, two primary forms of rat M-type subunit cDNA's were detected. Although the translated regions of these mRNA's were essentially identical, the 5'-untranslated region (5'-UTR) exhibited different lengths (90 or 59 bp) and sequences. Each M-type subunit cDNA had 10 common nucleotides immediately upstream from the initiator ATG, and the remaining 5'-UTR's had insignificant identity. A genomic fragment which interacted with probes complimentary to the sequences of the 5'-UTR of each M-type subunit mRNA isoform was isolated and sequenced by primer walking. It was discovered that the 5'-UTR of one of the mRNA's (proximal mRNA) was located immediately upstream from exon I and was apparently transcribed without splicing. Subsequently, the initial bp in the sequence of the other mRNA isoform (distal mRNA) was located 4010 bp upstream from the ATG in exon 1. Employing Reverse Transcription-Polymerase Chain Reaction using total RNA and scanning densitometry, the relative levels of the proximal and distal mRNA's during neonatal maturation of brain, heart, and muscle were measured. In these tissues, both forms of M-type subunit mRNA's were present, and during maturation tissue-specific differences were noted.
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Affiliation(s)
- Y Mhaskar
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794-9629, USA
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45
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Reuter R, Naumann M, Bär J, Haferburg D, Kopperschläger G. Purification, molecular and kinetic characterization of phosphofructokinase-1 from the yeast Schizosaccharomyces pombe: evidence for an unusual subunit composition. Yeast 2000; 16:1273-85. [PMID: 11015725 DOI: 10.1002/1097-0061(200010)16:14<1273::aid-yea621>3.0.co;2-#] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphofructokinase-1 (Pfk-1) from Schizosaccharomyces pombe was purified by 54-fold enrichment to homogeneity elaborating the following steps: (a) Disruption of the cells with glass beads; (b) fractionated precipitation with polyethylene glycol 6000; (c) affinity chromatography on Cibacron-Blue F3G-A-Sephadex G 100; (d) ion exchange chromatography on Resource Q. The native enzyme exhibits a mass of 790+/-30 kDa, as detected by sedimentation equilibrium measurements. The apparent sedimentation coefficient was found to be s(20,c)=20.2+/-0.3 S. No significant dependence of the s-value on the protein concentration was observed in the range 0. 07-0.7 mg/ml. Polyacrylamide gel electrophoresis in presence of sodium dodecyl sulphate and MALDI-TOF spectra showed that the enzyme is composed of subunits of identical size of 100+/-5 kDa, forming an octameric structure. The N-terminus of the enzyme was found to be blocked. Sequences of tryptic and chymotryptic peptides of the subunit coincide with the proposed amino acid sequence as deduced from the gene from the EMBL library. The Pfk-1 coding sequence of S. pombe was transformed into a Pfk-1 double deletion mutants of Saccharomyces cerevisiae resulting in glucose-positive cells with enzyme activity in the crude cell extract. The kinetic analysis revealed less cooperativity to fructose 6-phosphate (n(H)=1.6) and less inhibition by ATP as compared to the enzyme from baker's yeast. Fructose 2,6-bisphosphate (in micromolar range) and AMP (in millimolar range) were found to overcome ATP inhibition and to increase the affinity to fructose 6-phosphate.
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Affiliation(s)
- R Reuter
- Institut für Biochemie, Medizinische Fakultät, Universität Leipzig, Liebigstrasse 16, 04103 Leipzig, Germany
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Gansser G, Kneist S, Stösser L, Kaufmann M. Differences in acidogenicity of S. sobrinus and S. rattus are linked to the catalytic efficiency of the glycolytic key enzyme phosphofructokinase. Caries Res 2000; 34:412-7. [PMID: 11014908 DOI: 10.1159/000016616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
This contribution describes the biochemical properties of two catalytically different phosphofructokinases (PFKs) purified from Streptococcus rattus LB 2 (PFK-rat) and Streptococcus sobrinus OMZ 65 (PFK-sob), respectively. Steady-state kinetics revealed K(M) = 0. 8 mM for PFK-rat and K(M) = 0.08 mM for PFK-sob for F-6-P as the substrate. The enzymes also differ in their pH profiles: whereas the highest activity of PFK-rat was measured at pH = 8.0, the optimum pH of PFK-sob was at pH = 7.0. In addition, compared to PFK-sob, PFK-rat was more sensitive against the allosteric inhibitor ATP. PFK catalyzes a committed step of glycolysis, the main acid producing catabolic pathway. Thus, the catalytically more efficient enzyme isolated from S. sobrinus OMZ 65, especially at low pH, could explain the comparably high acidogenicity of this strain.
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Affiliation(s)
- G Gansser
- Institute for Biochemistry, University of Witten/Herdecke, Witten, Germany
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Bär J, Golbik R, Hübner G, Kopperschläger G. Denaturation of phosphofructokinase-1 from Saccharomyces cerevisiae by guanidinium chloride and reconstitution of the unfolded subunits to their catalytically active form. Biochemistry 2000; 39:6960-8. [PMID: 10841778 DOI: 10.1021/bi9928142] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Unfolding and refolding of heterooctameric phosphofructokinase-1 from Saccharomyces cerevisiae were investigated by application of kinetic, hydrodynamic, and spectroscopic methods and by use of guanidinium chloride (GdmCl) as denaturant. Inactivation of the enzyme starts at about 0.3 M GdmCl and undergoes a sharp unfolding transition in a narrow range of the denaturant concentration. The inactivation is accompanied by a dissociation of the enzyme into dimers (at 0.6 M GdmCl), which could be detected by changes of the circular dichroism and intrinsic fluorescence. Protein aggregates were observed from 0.7 to 1.5 M GdmCl that unfold at higher denaturant concentrations. Refolding of chemically denatured phosphofructokinase proceeds as a stepwise process via the generation of elements of secondary structure, the formation of assembly-competent monomers that associate to heterodimers and the assembly of dimers to heterotetramers and heterooctamers. The assembly reactions seem to be rate-limiting. Recovery of the enzyme activity (maximum 65%) competes with an nonproductive aggregation of the subunits. alpha-Cyclodextrin functions as an artificial chaperone by preventing aggregation of the subunits, whereas ATP is suggested to support the generation of heterodimers that are competent to a further assembly.
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Affiliation(s)
- J Bär
- Institut für Biochemie, Universitätsklinikum, Universität Leipzig, Liebigstrasse 16, D-04103 Leipzig, Germany
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Sánchez-Martínez C, Estévez AM, Aragón JJ. Phosphofructokinase C isozyme from ascites tumor cells: cloning, expression, and properties. Biochem Biophys Res Commun 2000; 271:635-40. [PMID: 10814514 DOI: 10.1006/bbrc.2000.2681] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The phosphofructokinase C isozyme (PFK-C) from ascites tumor cells has been cloned and characterized to investigate the particular properties of PFK activity in this type of cells. The isolated cDNA encodes a protein of 784 amino acids and 85.5 kDa, whose expression was constant along tumor growth and markedly decreased when cell proliferation stops. The enzyme was functionally expressed in a PFK-deficient strain of Saccharomyces cerevisiae and purified to homogeneity. Recombinant PFK-C exhibited the same subunit size as the tumor wild-type isozyme and its steady-state kinetic parameters were similar to those of the form present in normal cells. The regulatory properties of the C isozyme accounted for the lack of fructose-1,6-P(2) activation and the P-enolpyruvate inhibition of PFK activity observed in ascites tumor preparations containing the various isozyme types. Nevertheless, PFK-C binds fructose-1,6-P(2) to an allosteric site as suggested by protection against thermal denaturation. Our results indicate that glucose metabolism in tumor cells is not regulated by a mutant form of PFK-C but by a high level expression of the normal C isozyme.
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Affiliation(s)
- C Sánchez-Martínez
- Departamento de Bioquímica, Facultad de Medicina de la Universidad Autónoma, Madrid, 28029, Spain
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Guixé V. Chemical modification of SH groups of E. coli phosphofructokinase-2 induces subunit dissociation: monomers are inactive but preserve ligand binding properties. Arch Biochem Biophys 2000; 376:313-9. [PMID: 10775417 DOI: 10.1006/abbi.2000.1718] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Modification of Escherichia coli phosphofructokinase-2 (Pfk-2) with N-(1-pyrenil)maleimide results in an enzyme form that is inactive. However, the rate of modification is drastically reduced in the presence of the allosteric effector MgATP. The stoichiometry of the label incorporation was found to be 2.03 +/- 0.035 mol of the reagent/mol of subunit, in agreement with the number of titratable SH groups by 5,5'-dithiobis(2-nitrobenzoic acid) in the labeled protein. HPLC gel filtration experiments demonstrate that native Pfk-2 is a dimer in the absence of ligands, while in the presence of MgATP a dimer-tetramer transition is promoted. In contrast, the modified enzyme eluted as a monomer and the presence of MgATP was not able to induce aggregation. Although the modified monomers are inactive, the dissociation constants for the substrates and the allosteric effector MgATP, measured by following the fluorescence of the binding probe, are the same as for the native enzyme. Quenching of pyrene fluorescence emission of labeled phosphofructokinase-2 monomers by acrylamide gave downward curved Stern-Volmer plots, with very similar quenching efficiencies for the control and for the fructose-6-P and MgATP-enzyme complexes. These results show the presence of SH groups in the interface of Pfk-2 subunits, critical for subunit interactions, and that conformational changes occurring through the dimers are essential for catalytic activity.
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Affiliation(s)
- V Guixé
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
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Sawada M, Mitsui Y, Sugiya H, Furuyama S. Ribose 1,5-bisphosphate is a putative regulator of fructose 6-phosphate/fructose 1,6-bisphosphate cycle in liver. Int J Biochem Cell Biol 2000; 32:447-54. [PMID: 10762070 DOI: 10.1016/s1357-2725(99)00137-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
6-Phosphofructo-1-kinase and fructose-1,6-bisphosphatase are rate-limiting enzymes for glycolysis and gluconeogenesis respectively, in the fructose 6-phosphate/fructose 1,6-bisphosphate cycle in the liver. The effect of ribose 1,5-bisphosphate on the enzymes was investigated. Ribose 1,5-bisphosphate synergistically relieved the ATP inhibition and increased the affinity of liver 6-phosphofructo-1-kinase for fructose 6-phosphate in the presence of AMP. Ribose 1,5-bisphosphate synergistically inhibited fructose-1,6-bisphosphatase in the presence of AMP. The activating effect on 6-phosphofructo-1-kinase and the inhibitory effect on fructose-1,6-bisphosphatase suggest ribose 1,5-bisphosphate is a potent regulator of the fructose 6-phosphate/fructose 1,6-bisphosphate cycle in the liver.
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Affiliation(s)
- M Sawada
- Department of Physiology, Nihon University School of Dentistry at Matsudo, Chiba, Japan
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