1
|
Chen L, Zhao X, He Y, Yang H. Cloning, purification and characterisation of cytosolic fructose-1,6-bisphosphatase from mung bean (Vigna radiata). Food Chem 2021; 347:128973. [PMID: 33444888 DOI: 10.1016/j.foodchem.2020.128973] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 11/26/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
To improve the crop yield and quality, the cytosolic fructose-1,6-bisphosphatase (cFBPase) from mung bean (Vigna radiata), a rate-limiting enzyme in gluconeogenesis, was cloned, purified, and structurally characterised. To function it required Mg2+ and Mn2+ at 0.01-10 mM. The Michaelis-Menton constant and adenosine monophosphate (AMP) inhibitory constant (Ki) were 7.96 and 111.09 μM, respectively. The functional site residues of AMP binding (Arg30, Asp32, and Phe33) and the active site residues (Asn218 and Met251) were tested via site-directed mutagenesis and molecular docking. Asn218 and Met251 were replaced by Tyr and Leu, respectively. The M251L mutant showed enhanced substrate affinity and activity, resulting from decreased binding energy (-2.58 kcal·mol-1) and molecular distance (4.2 Å). AMP binding site mutations changed the enzyme activities, indicating a connection between the binding and active sites. Furthermore, Ki and docking analysis revealed that Asp32 plays a key role in maintaining the AMP binding conformation.
Collapse
Affiliation(s)
- Lin Chen
- Department of Food Science and Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China
| | - Xue Zhao
- Department of Food Science and Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China
| | - Yun He
- Department of Food Science and Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China
| | - Hongshun Yang
- Department of Food Science and Technology, National University of Singapore, Singapore 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China.
| |
Collapse
|
2
|
Asenjo JL, Ludwig HC, Droppelmann CA, Cárcamo JG, Concha II, Yáñez AJ, Cárdenas ML, Cornish-Bowden A, Slebe JC. Subunit interactions in pig-kidney fructose-1,6-bisphosphatase: Binding of substrate induces a second class of site with lowered affinity and catalytic activity. Biochim Biophys Acta Gen Subj 2014; 1840:1798-807. [DOI: 10.1016/j.bbagen.2013.12.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/28/2013] [Accepted: 12/23/2013] [Indexed: 10/25/2022]
|
3
|
Tayyem RF, Zalloum HM, Elmaghrabi MR, Yousef AM, Mubarak MS. Ligand-based designing, in silico screening, and biological evaluation of new potent fructose-1,6-bisphosphatase (FBPase) inhibitors. Eur J Med Chem 2012; 56:70-95. [DOI: 10.1016/j.ejmech.2012.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Revised: 07/27/2012] [Accepted: 08/02/2012] [Indexed: 10/28/2022]
|
4
|
Mohler ML, He Y, Wu Z, Hwang DJ, Miller DD. Recent and emerging anti-diabetes targets. Med Res Rev 2009; 29:125-95. [DOI: 10.1002/med.20142] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
5
|
Hines JK, Chen X, Nix JC, Fromm HJ, Honzatko RB. Structures of mammalian and bacterial fructose-1,6-bisphosphatase reveal the basis for synergism in AMP/fructose 2,6-bisphosphate inhibition. J Biol Chem 2007; 282:36121-31. [PMID: 17933867 DOI: 10.1074/jbc.m707302200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fructose-1,6-bisphosphatase (FBPase) operates at a control point in mammalian gluconeogenesis, being inhibited synergistically by fructose 2,6-bisphosphate (Fru-2,6-P(2)) and AMP. AMP and Fru-2,6-P(2) bind to allosteric and active sites, respectively, but the mechanism responsible for AMP/Fru-2,6-P(2) synergy is unclear. Demonstrated here for the first time is a global conformational change in porcine FBPase induced by Fru-2,6-P(2) in the absence of AMP. The Fru-2,6-P(2) complex exhibits a subunit pair rotation of 13 degrees from the R-state (compared with the 15 degrees rotation of the T-state AMP complex) with active site loops in the disengaged conformation. A three-state thermodynamic model in which Fru-2,6-P(2) drives a conformational change to a T-like intermediate state can account for AMP/Fru-2,6-P(2) synergism in mammalian FBPases. AMP and Fru-2,6-P(2) are not synergistic inhibitors of the Type I FBPase from Escherichia coli, and consistent with that model, the complex of E. coli FBPase with Fru-2,6-P(2) remains in the R-state with dynamic loops in the engaged conformation. Evidently in porcine FBPase, the actions of AMP at the allosteric site and Fru-2,6-P(2) at the active site displace engaged dynamic loops by distinct mechanisms, resulting in similar quaternary end-states. Conceivably, Type I FBPases from all eukaryotes may undergo similar global conformational changes in response to Fru-2,6-P(2) ligation.
Collapse
Affiliation(s)
- Justin K Hines
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA
| | | | | | | | | |
Collapse
|
6
|
Ludwig HC, Pardo FN, Asenjo JL, Maureira MA, Yañez AJ, Slebe JC. Unraveling multistate unfolding of pig kidney fructose-1,6-bisphosphatase using single tryptophan mutants. FEBS J 2007; 274:5337-49. [PMID: 17894826 DOI: 10.1111/j.1742-4658.2007.06059.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pig kidney fructose-1,6-bisphosphatase is a homotetrameric enzyme which does not contain tryptophan. In a previous report the guanidine hydrochloride-induced unfolding of the enzyme has been described as a multistate process [Reyes, A. M., Ludwig, H. C., Yañez, A. J., Rodriguez, P. H and Slebe, J. C. (2003) Biochemistry 42, 6956-6964]. To monitor spectroscopically the unfolding transitions, four mutants were constructed containing a single tryptophan residue either near the C1-C2 or the C1-C4 intersubunit interface of the tetramer. The mutants were shown to retain essentially all of the structural and kinetic properties of the enzyme isolated from pig kidney. The enzymatic activity, intrinsic fluorescence, size-exclusion chromatographic profiles and 1-anilinonaphthalene-8-sulfonate binding by the mutants were studied under unfolding equilibrium conditions. The unfolding profiles were multisteps, and formation of hydrophobic structures was detected. The enzymatic activity of wild-type and mutant FBPases as a function of guanidine hydrochloride concentration showed an initial enhancement (maximum approximately 30%) followed by a biphasic decay. The activity and fluorescence results indicate that these transitions involve conformational changes in the fructose-1,6-bisphosphate and AMP domains. The representation of intrinsic fluorescence data as a 'phase diagram' reveals the existence of five intermediates, including two catalytically active intermediates that have not been previously described, and provides the first spectroscopic evidence for the formation of dimers. The intrinsic fluorescence unfolding profiles indicate that the dimers are formed by selective disruption of the C1-C2 interface.
Collapse
Affiliation(s)
- Heide C Ludwig
- Instituto de Bioquímica, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | | | | | | | | | | |
Collapse
|
7
|
Abstract
Fructose 2,6-bisphosphate is a potent metabolic regulator in eukaryotic organisms; it affects the activity of key enzymes of the glycolytic and gluconeogenic pathways. The enzymes responsible for its synthesis and hydrolysis, 6-phosphofructo-2-kinase (PFK-2) and fructose-2,6-bisphosphatase (FBPase-2) are present in representatives of all major eukaryotic taxa. Results from a bioinformatics analysis of genome databases suggest that very early in evolution, in a common ancestor of all extant eukaryotes, distinct genes encoding PFK-2 and FBPase-2, or related enzymes with broader substrate specificity, fused resulting in a bifunctional enzyme both domains of which had, or later acquired, specificity for fructose 2,6-bisphosphate. Subsequently, in different phylogenetic lineages duplications of the gene of the bifunctional enzyme occurred, allowing the development of distinct isoenzymes for expression in different tissues, at specific developmental stages or under different nutritional conditions. Independently in different lineages of many unicellular eukaryotes one of the domains of the different PFK-2/FBPase-2 isoforms has undergone substitutions of critical catalytic residues, or deletions rendering some enzymes monofunctional. In a considerable number of other unicellular eukaryotes, mainly parasitic organisms, the enzyme seems to have been lost altogether. Besides the catalytic core, the PFK-2/FBPase-2 has often N- and C-terminal extensions which show little sequence conservation. The N-terminal extension in particular can vary considerably in length, and seems to have acquired motifs which, in a lineage-specific manner, may be responsible for regulation of catalytic activities, by phosphorylation or ligand binding, or for mediating protein-protein interactions.
Collapse
Affiliation(s)
- Paul A M Michels
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université Catholique de Louvain, Brussels, Belgium.
| | | |
Collapse
|
8
|
Silberstein M, Dennis S, Brown L, Kortvelyesi T, Clodfelter K, Vajda S. Identification of substrate binding sites in enzymes by computational solvent mapping. J Mol Biol 2003; 332:1095-113. [PMID: 14499612 DOI: 10.1016/j.jmb.2003.08.019] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Enzyme structures determined in organic solvents show that most organic molecules cluster in the active site, delineating the binding pocket. We have developed algorithms to perform solvent mapping computationally, rather than experimentally, by placing molecular probes (small molecules or functional groups) on a protein surface, and finding the regions with the most favorable binding free energy. The method then finds the consensus site that binds the highest number of different probes. The probe-protein interactions at this site are compared to the intermolecular interactions seen in the known complexes of the enzyme with various ligands (substrate analogs, products, and inhibitors). We have mapped thermolysin, for which experimental mapping results are also available, and six further enzymes that have no experimental mapping data, but whose binding sites are well characterized. With the exception of haloalkane dehalogenase, which binds very small substrates in a narrow channel, the consensus site found by the mapping is always a major subsite of the substrate-binding site. Furthermore, the probes at this location form hydrogen bonds and non-bonded interactions with the same residues that interact with the specific ligands of the enzyme. Thus, once the structure of an enzyme is known, computational solvent mapping can provide detailed and reliable information on its substrate-binding site. Calculations on ligand-bound and apo structures of enzymes show that the mapping results are not very sensitive to moderate variations in the protein coordinates.
Collapse
|
9
|
Ludwig HC, Herrera R, Reyes AM, Hubert E, Slebe JC. Suppression of kinetic AMP cooperativity of fructose-1,6-bisphosphatase by carbamoylation of lysine 50. JOURNAL OF PROTEIN CHEMISTRY 1999; 18:533-45. [PMID: 10524771 DOI: 10.1023/a:1020647116022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Selective treatment of pig kidney fructose 1,6-bisphosphatase with cyanate leads to the formation of an active carbamoylated derivative that shows no cooperative interaction between the AMP-binding sites, but completely retains the sensitivity to the inhibitor. By an exhaustive carbamoylation of the enzyme a derivative is formed that has a complete loss of cooperativity and a decrease of sensitivity to AMP. It was proposed that the observed changes of allosteric properties were due to the chemical modification of two lysine residues per enzyme subunit [Slebe et al. (1983), J. Protein Chem. 2, 437-443]. Studies of the temperature dependence of AMP sensitivity and the interaction with Cibacron Blue Sepharose of carbamoylated fructose 1,6-bisphosphatase derivatives indicate that the lysine residue involved in AMP sensitivity is located at the allosteric AMP site, while the lysine residue involved in AMP cooperativity is at a distinct location. Using [14C]cyanate, we identified both lysine residues in the primary structure of the enzyme; Lys50 is essential for AMP cooperativity and Lys112 appears to be the reactive residue involved in the AMP sensitivity. According to the fructose 1,6-bisphosphatase crystal structure, Lys50 is strategically positioned at the C1-C2 interface, near the molecular center of the tetramer, and Lys112 is in the AMP-binding site. The results reported here, combined with the structural data of the enzyme, strongly suggest that the C1-C2 interface is critical for the propagation of the allosteric signal among the AMP sites on different subunits.
Collapse
Affiliation(s)
- H C Ludwig
- Instituto de Bioquímica, Facultad de Ciencias, Universidad Austral de Chile, Valdivia
| | | | | | | | | |
Collapse
|
10
|
Hodgson RJ, Jia Z, Plaxton WC. A fluorescence study of ligand-induced conformational changes in cytosolic fructose-1,6-bisphosphatase from germinating castor oil seeds. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1388:285-94. [PMID: 9858750 DOI: 10.1016/s0167-4838(98)00176-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The intrinsic fluorescence of homogeneous castor oil seed cytosolic fructose-1,6-bisphosphatase (FBPasec) was used as an indicator of conformational changes due to ligand binding. Binding of the substrate and the inhibitor fructose-2,6-bisphosphate (F-2,6-P2) was quantitatively compared to their respective kinetic effects on enzymatic activity. There are two distinct types of substrate interaction with FBPasec, corresponding to catalytic and inhibitory binding, respectively. Inhibitory substrate binding shares several characteristics with F-2,6-P2 binding which indicates that both ligands bind at the same site. However, F-2,6-P2 does not prevent fluorescence transitions attributed to catalytic substrate binding. The marked synergistic inhibition of FBPasec by AMP and F-2,6-P2 appears to arise via AMP's promotion of F-2,6-P2 binding. Based on the X-ray crystal structure of porcine kidney FBPase our modelling studies suggest the existence of a distinct F-1,6-P2/F-2,6-P2 inhibitory binding site which partially overlaps with the enzyme's catalytic site. We propose that a pronounced allosteric transition mediated by AMP binding increases access of F-1,6-P2 and F-2,6-P2 to this common inhibitory binding site.
Collapse
Affiliation(s)
- R J Hodgson
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | | | | |
Collapse
|
11
|
Kurbanov FT, Choe JY, Honzatko RB, Fromm HJ. Directed mutations in the poorly defined region of porcine liver fructose-1,6-bisphosphatase significantly affect catalysis and the mechanism of AMP inhibition. J Biol Chem 1998; 273:17511-6. [PMID: 9651342 DOI: 10.1074/jbc.273.28.17511] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Asn64, Asp68, Lys71, Lys72, and Asp74 of porcine liver fructose-1, 6-bisphosphatase (FBPase) are conserved residues and part of a loop for which no electron density has been observed in crystal structures. Yet mutations of the above dramatically affect catalytic rates and/or AMP inhibition. The Asp74 --> Ala and Asp74 --> Asn mutant enzymes exhibited 50,000- and 2,000-fold reductions, respectively, in kcat relative to wild-type FBPase. The pH optimum for the catalytic activity of the Asp74 --> Glu, Asp68 --> Glu, Asn64 --> Gln, and Asn64 --> Ala mutant enzymes shifted from pH 7.0 (wild-type enzyme) to pH 8.5, whereas the Lys71 --> Ala mutant and Lys71,72 --> Met double mutant had optimum activity at pH 7.5. Mg2+ cooperativity, Km for fructose 1,6-bisphosphate, and Ki for fructose 2,6-bisphosphate were comparable for the mutant and wild-type enzymes. Nevertheless, for the Asp74 --> Glu, Asp68 --> Glu, Asn64 --> Gln, and Asn64 --> Ala mutants, the binding affinity for Mg2+ decreased by 40-125-fold relative to the wild-type enzyme. In addition, the Asp74 --> Glu and Asn64 --> Ala mutants exhibited no AMP cooperativity, and the kinetic mechanism of AMP inhibition with respect to Mg2+ was changed from competitive to noncompetitive. The double mutation Lys71,72 --> Met increased Ki for AMP by 175-fold and increased Mg2+ affinity by 2-fold relative to wild-type FBPase. The results reported here strongly suggest that loop 51-72 is important for catalytic activity and the mechanism of allosteric inhibition of FBPase by AMP.
Collapse
Affiliation(s)
- F T Kurbanov
- Department of Biochemistry and Biophysics, Iowa State University, Ames, Iowa 50011, USA
| | | | | | | |
Collapse
|
12
|
Iversen LF, Brzozowski M, Hastrup S, Hubbard R, Kastrup JS, Larsen IK, Naerum L, Nørskov-Lauridsen L, Rasmussen PB, Thim L, Wiberg FC, Lundgren K. Characterization of the allosteric binding pocket of human liver fructose-1,6-bisphosphatase by protein crystallography and inhibitor activity studies. Protein Sci 1997; 6:971-82. [PMID: 9144768 PMCID: PMC2143689 DOI: 10.1002/pro.5560060503] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The structures of three complexes of human fructose-1,6-bisphosphatase (FB) with the allosteric inhibitor AMP and two AMP analogues have been determined and all fully refined. The data used for structure determination were collected at cryogenic temperature (110 K), and with the use of synchrotron radiation. The structures reveal a common mode of binding for AMP and formycine monophosphate (FMP). 5-Amino-4-carboxamido-1 beta-D-5-phosphate-ribofuranosyl-1H-imidazole (AICAR-P) shows an unexpected mode of binding to FB, different from that of the other two ligands. The imidazole ring of AICAR-P is rotated 180 degrees compared to the AMP and FMP bases. This rotation results in a slightly different hydrogen bonding pattern and minor changes in the water structure in the binding pocket. Common features of binding are seen for the ribose and phosphate moieties of all three compounds. Although binding in a different mode, AICAR-P is still capable of making all the important interactions with the residues building the allosteric binding pocket. The IC50 values of AMP, FMP, and AICAR-P were determined to be 1.7, 1.4, and 20.9 microM, respectively. Thus, the approximately 10 times lower potency of AICAR-P is difficult to explain solely from the variations observed in the binding pocket. Only one water molecule in the allosteric binding pocket was found to be conserved in all four subunits in all three structures. This water molecule coordinates to a phosphate oxygen atom and the N7 atom of the AMP molecule, and to similarly situated atoms in the FMP and AICAR-P complexes. This implies an important role of the conserved water molecule in binding of the ligand.
Collapse
Affiliation(s)
- L F Iversen
- Department of Medicinal Chemistry, Royal Danish School of Pharmacy, Copenhagen, Denmark.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Lu G, Giroux EL, Kantrowitz ER. Importance of the dimer-dimer interface for allosteric signal transduction and AMP cooperativity of pig kidney fructose-1,6-bisphosphatase. Site-specific mutagenesis studies of Glu-192 and Asp-187 residues on the 190's loop. J Biol Chem 1997; 272:5076-81. [PMID: 9030572 DOI: 10.1074/jbc.272.8.5076] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The role of the 190's loop of fructose-1,6-bisphosphatase (Fru-1, 6-P2ase) in the allosteric regulation of Fru-1,6-P2ase has been investigated through kinetic studies on three mutant enzymes, Glu-192 --> Ala, Glu-192 --> Gln, and Asp-187 --> Ala. AMP is an allosteric inhibitor, which binds to the regulatory sites and induces the R- to T-state transition; for wild-type Fru-1,6-P2ase AMP inhibition is cooperative with a Hill coefficient of 2.0. The replacement of Asp-187, which forms an interaction across the C1:C2 monomer-monomer interface, with alanine did not change the catalytic efficiency, and it had no effect on the cooperativity of AMP inhibition; however, the apparent dissociation constant for AMP increased more than 4-fold as compared to the value for the wild-type enzyme. The replacement of Glu-192, which forms interactions across the C1:C4 dimer-dimer interface, with Ala and Gln lowered kcat from 21 s-1 for wild-type enzyme to 15 s-1 and 13 s-1, respectively, for the mutant enzymes, while their respective Km values were not changed. However, these replacements did have dramatic effects on AMP inhibition; first, cooperative AMP inhibition was lost; second, the AMP inhibition was biphasic, which can be interpreted as due to AMP binding to two classes of binding sites. The high affinity class of sites corresponds to the regulatory sites, while the low affinity class of sites may be the active sites. The results reported here, combined with the structural and kinetic results from the Lys-42 --> Ala enzyme, strongly suggest that the C1:C4 dimer-dimer interface, rather than the C1:C2 monomer-monomer interface, is critical for the propagation of the allosteric signal between the AMP sites on different subunits; in addition, cooperative AMP inhibition is essential for the enzyme to be fully inhibited by the binding of AMP to the allosteric site.
Collapse
Affiliation(s)
- G Lu
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02167, USA
| | | | | |
Collapse
|
14
|
Sträter N, Lipscomb WN, Klabunde T, Krebs B. Enzymatische Acyl- und Phosphoryltransferreaktionen unter Beteiligung von zwei Metallionen. Angew Chem Int Ed Engl 1996. [DOI: 10.1002/ange.19961081804] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
15
|
Kaiser R, Olsson H, Erman M, Weeks CM, Hjelmqvist L, Ghosh D, Jörnvall H. Fructose-1,6-bisphosphatase. Primary structure of the rabbit liver enzyme. 'Intermediate' variability of an oligomeric protein. FEBS Lett 1996; 389:249-52. [PMID: 8766709 DOI: 10.1016/0014-5793(96)00594-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The primary structure of rabbit liver fructose-1,6-bisphosphatase was determined by peptide analysis of digests with different proteases. The results establish the primary structure, complete data bank entries, and show that this enzyme variant is indeed homologous with other liver fructose-1,6-bisphosphatases. Residue differences with the enzymes from other mammals are 9-15%, with those from plants and yeasts about 50%, and with those from characterized prokaryotes up to 70%, showing an enzyme variability intermediate between those of 'variable' and 'constant' oligomeric dehydrogenases. Structural relationships, conformations and catalytic mechanisms are consistent within the family of fructose-1,6-bisphosphatases, and the rabbit protein is a typical rather than an aberrant form of the enzyme.
Collapse
Affiliation(s)
- R Kaiser
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | | | | | | | | | | | | |
Collapse
|
16
|
Shyur LF, Aleshin AE, Honzatko RB, Fromm HJ. Site-directed mutagenesis of residues at subunit interfaces of porcine fructose-1,6-bisphosphatase. J Biol Chem 1996; 271:3005-10. [PMID: 8621693 DOI: 10.1074/jbc.271.6.3005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Mutation of Arg-15, Glu-19, Arg-22, and Thr-27 of porcine liver fructose-1,6-bisphosphatase was carried out by site-directed mutagenesis. These residues are conserved in all known primary sequences of mammalian fructose-1,6-bisphosphatase. On the basis of the crystal structure of the enzyme, Arg-15, Glu-19, and Arg-22 are located at the interface of the two dimers (C1-C2 and C3-C4), and Thr-27 is in the AMP binding site. The wild-type and mutant forms of the enzyme were purified to homogeneity and characterized by initial rate kinetics and circular dichroism (CD) spectrometry. No discernible differences were observed between the secondary structures of the wild-type and mutant forms of fructose-1, 6-bisphosphatase on the basis of CD data. Kinetic analyses revealed similar kcat values for mutants R15A, E19Q, R22K, and T27A of fructose-1,6-bisphosphatase; however, a 2-fold increase of kcat was observed with R22M compared with that of the wild-type enzyme. Small changes in Km values for fructose-1,6-bisphosphate were found in the five mutants. 4 6-fold decreases in Ki values for fructose 2,6-bisphosphate and 5-9-fold decreases in the binding affinity of Mg2+ relative to the wild-type enzyme were exhibited by R15A and E19Q. No alteration of Mg2+ cooperativity was found in the five mutants. Significant changes in Ki values for AMP were obtained in the case of R22K (30-fold) and T27A (1300-fold) with a Hill coefficient of 2.0. Replacement of Arg-22 with methionine, however, caused the total loss of AMP cooperativity without changing AMP affinity. Modeling of the mutant structures was undertaken in an attempt to define the functional role of Arg-22. These studies link specific interactions between subunits in fructose-1,6-bisphosphatase to observed properties of cooperativity.
Collapse
Affiliation(s)
- L F Shyur
- Department of Biochemistry and Biophysics, Iowa State University, Ames, Iowa 50011, USA
| | | | | | | |
Collapse
|
17
|
Villeret V, Huang S, Fromm HJ, Lipscomb WN. Crystallographic evidence for the action of potassium, thallium, and lithium ions on fructose-1,6-bisphosphatase. Proc Natl Acad Sci U S A 1995; 92:8916-20. [PMID: 7568043 PMCID: PMC41078 DOI: 10.1073/pnas.92.19.8916] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Fructose-1,6-bisphosphatase (Fru-1,6-Pase; D-fructose-1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11) requires two divalent metal ions to hydrolyze alpha-D-fructose 1,6-bisphosphate. Although not required for catalysis, monovalent cations modify the enzyme activity; K+ and Tl+ ions are activators, whereas Li+ ions are inhibitors. Their mechanisms of action are still unknown. We report here crystallographic structures of pig kidney Fru-1,6-Pase complexed with K+, Tl+, or both Tl+ and Li+. In the T form Fru-1,6-Pase complexed with the substrate analogue 2,5-anhydro-D-glucitol 1,6-bisphosphate (AhG-1,6-P2) and Tl+ or K+ ions, three Tl+ or K+ binding sites are found. Site 1 is defined by Glu-97, Asp-118, Asp-121, Glu-280, and a 1-phosphate oxygen of AhG-1,6-P2; site 2 is defined by Glu-97, Glu-98, Asp-118, and Leu-120. Finally, site 3 is defined by Arg-276, Glu-280, and the 1-phosphate group of AhG-1,6-P2. The Tl+ or K+ ions at sites 1 and 2 are very close to the positions previously identified for the divalent metal ions. Site 3 is specific to K+ or Tl+. In the divalent metal ion complexes, site 3 is occupied by the guanidinium group of Arg-276. These observations suggest that Tl+ or K+ ions can substitute for Arg-276 in the active site and polarize the 1-phosphate group, thus facilitating nucleophilic attack on the phosphorus center. In the T form complexed with both Tl+ and Li+ ions, Li+ replaces Tl+ at metal site 1. Inhibition by lithium very likely occurs as it binds to this site, thus retarding turnover or phosphate release. The present study provides a structural basis for a similar mechanism of inhibition for inositol monophosphatase, one of the potential targets of lithium ions in the treatment of manic depression.
Collapse
Affiliation(s)
- V Villeret
- Gibbs Chemical Laboratory Harvard University, Cambridge, MA 02138, USA
| | | | | | | |
Collapse
|
18
|
Xue Y, Huang S, Liang JY, Zhang Y, Lipscomb WN. Crystal structure of fructose-1,6-bisphosphatase complexed with fructose 2,6-bisphosphate, AMP, and Zn2+ at 2.0-A resolution: aspects of synergism between inhibitors. Proc Natl Acad Sci U S A 1994; 91:12482-6. [PMID: 7809062 PMCID: PMC45462 DOI: 10.1073/pnas.91.26.12482] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The crystal structure of fructose-1,6-bisphosphatase (Fru-1,6-Pase; EC 3.1.3.11) complexed with Zn2+ and two allosteric regulators, AMP and fructose 2,6-bisphosphate (Fru-2,6-P2) has been determined at 2.0-A resolution. In the refined model, the crystallographic R factor is 0.189 with rms deviations of 0.014 A and 2.8 degrees from ideal geometries for bond lengths and bond angles, respectively. A 15 degrees rotation is observed between the upper dimer C1C2 and the lower dimer C3C4 relative to the R-form structure (fructose 6-phosphate complex), consistent with that expected from a T-form structure. The major difference between the structure of the previously determined Fru-2,6-P2 complex (R form) and that of the current quaternary T-form complex lies in the active site domain. A zinc binding site distinct from the three binding sites established earlier was identified within each monomer. Helix H4 (residues 123-127) was found to be better defined than in previously studied ligated Fru-1,6-Pase structures. Interactions between monomers in the active site domain were found involving H4 residues from one monomer and residues Tyr-258 and Arg-243 from the adjacent monomer. Cooperativity between AMP and Fru-2,6-P2 in signal transmission probably involves the following features: an AMP site, the adjacent B3 strand (residues 113-118), the metal site, the immediate active site, the short helix H4 (residues 123-127), and Tyr-258 and Arg-243 from the adjacent monomer within the upper (or lower) dimer. The closest distance between the immediate active site and that on the adjacent monomer is only 5 A. Thus, the involvement of H4 in signal transmission adds another important pathway to the scheme of the allosteric mechanism of Fru-1,6-Pase.
Collapse
Affiliation(s)
- Y Xue
- Gibbs Chemical Laboratory, Harvard University, Cambridge, MA 02138
| | | | | | | | | |
Collapse
|
19
|
Bigl M, Eschrich K. Overexpression of catalytically active yeast (Saccharomyces cerevisiae) fructose-1,6-bisphosphatase in Escherichia coli. BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1994; 375:153-60. [PMID: 8011172 DOI: 10.1515/bchm3.1994.375.3.153] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
E. coli expression plasmids for yeast (Saccharomyces cerevisiae) fructose-1,6-bisphosphatase (EC 3.1.3.11) as wild-type enzyme and as lacZ fusion protein have been constructed from a pUC vector and a fragment of genomic yeast DNA. Both proteins were overexpressed in E. coli strain TG2 as enzymatically active soluble forms and purified to homogeneity. While the wild-type enzyme is indistinguishable from the authentic yeast enzyme with respect to molecular size, specific activity and kinetic properties, the lacZ fusion protein behaves differently. Being a tetramer like the wild-type enzyme, the specific activity of the purified fusion protein is lower than that of the native enzyme. In contrast to the wild-type enzyme the fusion fructose-1,6-bisphosphatase is not inhibited by excess substrate. Inhibition of the fusion protein by the most potent allosteric effectors of fructose-1,6-bisphosphatase, AMP and fructose 2,6-bisphosphate, is weaker than observed with the wild-type enzyme. The fusion protein but not the wild-type enzyme was found to bind to immobilized Procion Navy H-ER. This was employed to purify the fusion fructose-1,6-bisphosphatase by affinity chromatography. Polyclonal antibodies raised in rabbits against the fusion enzyme were found to cross-react with the wild-type enzyme, but not with E. coli proteins. Both fructose-1,6-bisphosphatases complement the fructose-1,6-bisphosphatase mutant DF656 of E. coli.
Collapse
Affiliation(s)
- M Bigl
- Institut für Biochemie, Bereich Medizin, Universität Leipzig, Germany
| | | |
Collapse
|
20
|
Daie J. Cytosolic fructose-1,6-bisphosphatase: A key enzyme in the sucrose biosynthetic pathway. PHOTOSYNTHESIS RESEARCH 1993; 38:5-14. [PMID: 24317825 DOI: 10.1007/bf00015056] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/1993] [Accepted: 06/29/1993] [Indexed: 05/05/2023]
Abstract
Fructose-1,6 bisphosphatase (FBPase) is a ubiquitous enzyme controlling a key reaction. In non-photosynthetic tissues, it regulates the rate of gluconeogenesis. In photosynthetic tissues, two FBPase isozymes (chloroplastic and cytosolic) play key roles in carbon assimilation and metabolism. The cytosolic FBPase is one of the regulatory enzymes in the sucrose biosynthetic pathway - its activity is regulated by both fine and coarse control mechanisms. Kinetic and allosteric properties of the plant cytosolic FBPase are remarkably similar to the mammalian and yeast FBPase, but differ greatly from those of the chloroplastic FBPase. Cytosolic FBPase is relatively conserved among various organisms both at amino acid and nucleotide sequence levels. There is slightly higher similarity between mammalian FBPase and plant cytosolic FBPase than there is between the two plant FBPases. Expression of plant cytosolic FBPase gene is developmentally regulated and appears to be coordinated with the expression of Rubisco and other carbon metabolism enzymes. Similar to the gluconeogenic FBPase, relatively rapid end product repression of FBPase gene occurs in plant. However, unlike the gluconeogenic FBPase, a concurrent decline in plant FBPase activity does not occur in response to increased end product levels. The physiological significance of FBPase gene repression, therefore, remains unclear in plants. Both expression and activity of the cytosolic FBPase are regulated by environmental factors such as light and drought conditions. Light-dependent modulation of FBPase activity in plants appears to involve some type of posttranslational modification. In addition to elucidating the exact nature of the presumed posttranslational modification, cloning of genomic and upstream sequences is needed before we fully understand the molecular regulation of the cytosolic FBPase in plants. Use of transgenic plants with altered rates of FBPase activity offers potential for enhanced crop productivity.
Collapse
Affiliation(s)
- J Daie
- Department of Botany, University of Wisconsin, Birge Hall, 53706, Madison, WI, USA
| |
Collapse
|
21
|
Liang JY, Zhang Y, Huang S, Lipscomb WN. Allosteric transition of fructose-1,6-bisphosphatase. Proc Natl Acad Sci U S A 1993; 90:2132-6. [PMID: 8384713 PMCID: PMC46039 DOI: 10.1073/pnas.90.6.2132] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Structural changes during the R-to-T transition of fructose-1,6-bisphosphatase (EC 3.1.3.11) form a hierarchy, in which structural changes at one level are supported by those at the other levels. The quaternary conformational changes involve a 17 degrees rotation between the upper and lower dimers, and a 3.4 degrees rotation between monomers in a dimer. Within monomers, the FBP domain, which remains rigid during the R-to-T transition, rotates 2.3 degrees relative to the AMP domain, which undergoes significant structural reorientations. The most important of these reorientations are the newly identified partially ordered loop residues 55-61 in the T state and reorientations of helices H1, H2, and H3. Supporting these structural changes are numerous readjustments of hydrogen bonding and van der Waals interactions throughout the entire tetrameric protein. Propagation of structural changes during the R-to-T transition relies primarily on helices H1, H2, H3, and loop 50-72. The change that begins at the AMP site causes reorientation of H1, H2, and H3 and changes of interactions across the C1-C4 (C2-C3) interface. These changes may propagate down H1, H2, H3, and loop 50-72 to affect interactions across the C1-C2 (C3-C4) and C1-C3 (C2-C4) interfaces. AMP inhibition is most probably caused by reduced metal binding affinity due to structural changes of metal ligands (Glu97, Asp118, and Asp121) in the active site. The eight-stranded beta-sheet, particularly the beta-strand B3, which connects Lys112 and Tyr113 of the AMP site with Asp118 and Asp121 of the metal site, may be responsible for communication between the AMP and active sites. Additional structural changes that support such communication include reorientation of the FBP domain and H1, H2, and H3 relative to the eight-stranded beta-sheet, and new conformations of loop 54-72 in the T state as AMP binds.
Collapse
Affiliation(s)
- J Y Liang
- Gibbs Chemical Laboratory, Harvard University, Cambridge, MA 02138
| | | | | | | |
Collapse
|