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Lustosa DM, Barkai S, Domb I, Milo A. Effect of Solvents on Proline Modified at the Secondary Sphere: A Multivariate Exploration. J Org Chem 2022; 87:1850-1857. [PMID: 35019660 PMCID: PMC9182215 DOI: 10.1021/acs.joc.1c02778] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The critical influence of solvent effects on proline-catalyzed aldol reactions has been extensively described. Herein, we apply multivariate regression strategies to probe the influence of different solvents on an aldol reaction catalyzed by proline modified at its secondary sphere with boronic acids. In this system, both in situ binding of the boronic acid to proline and the outcome of the aldol reaction are impacted by the solvent-controlled microenvironment. Thus, with the aim of uncovering mechanistic insight and an ancillary aim of identifying methodological improvements, we designed a set of experiments, spanning 15 boronic acids in five different solvents. Based on hypothesized intermediates or interactions that could be responsible for the selectivity in these reactions, we proposed several structural configurations for the library of boronic acids. Subsequently, we compared the statistical models correlating the outcome of the reaction in different solvents with molecular descriptors produced for each of these proposed configurations. The models allude to the importance of different interactions in controlling selectivity in each of the studied solvents. As a proof-of-concept for the practicality of our approach, the models in chloroform ultimately led to lowering the ketone loading to only two equivalents while retaining excellent yield and enantio- and diastereo-selectivity.
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Affiliation(s)
- Danilo M Lustosa
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Shahar Barkai
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Ido Domb
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Anat Milo
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
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2
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Heron PW, Sygusch J. Isomer activation controls stereospecificity of class I fructose-1,6-bisphosphate aldolases. J Biol Chem 2017; 292:19849-19860. [PMID: 28972169 DOI: 10.1074/jbc.m117.811034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/25/2017] [Indexed: 11/06/2022] Open
Abstract
Fructose-1,6-bisphosphate (FBP) aldolase, a glycolytic enzyme, catalyzes the reversible and stereospecific aldol addition of dihydroxyacetone phosphate (DHAP) and d-glyceraldehyde 3-phosphate (d-G3P) by an unresolved mechanism. To afford insight into the molecular determinants of FBP aldolase stereospecificity during aldol addition, a key ternary complex formed by DHAP and d-G3P, comprising 2% of the equilibrium population at physiological pH, was cryotrapped in the active site of Toxoplasma gondii aldolase crystals to high resolution. The growth of T. gondii aldolase crystals in acidic conditions enabled trapping of the ternary complex as a dominant population. The obligate 3(S)-4(R) stereochemistry at the nascent C3-C4 bond of FBP requires a si-face attack by the covalent DHAP nucleophile on the d-G3P aldehyde si-face in the active site. The cis-isomer of the d-G3P aldehyde, representing the dominant population trapped in the ternary complex, would lead to re-face attack on the aldehyde and yield tagatose 1,6-bisphosphate, a competitive inhibitor of the enzyme. We propose that unhindered rotational isomerization by the d-G3P aldehyde moiety in the ternary complex generates the active trans-isomer competent for carbonyl bond activation by active-site residues, thereby enabling si-face attack by the DHAP enamine. C-C bond formation by the cis-isomer is suppressed by hydrogen bonding of the cis-aldehyde carbonyl with the DHAP enamine phosphate dianion through a tetrahedrally coordinated water molecule. The active site geometry further suppresses C-C bond formation with the l-G3P enantiomer of d-G3P. Understanding C-C formation is of fundamental importance in biological reactions and has considerable relevance to biosynthetic reactions in organic chemistry.
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Affiliation(s)
- Paul W Heron
- From the Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Jurgen Sygusch
- From the Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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3
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de Gracia Retamosa M, de Cózar A, Sánchez M, Miranda JI, Sansano JM, Castelló LM, Nájera C, Jiménez AI, Sayago FJ, Cativiela C, Cossío FP. Remote Substituent Effects on the Stereoselectivity and Organocatalytic Activity of Densely Substituted Unnatural Proline Esters in Aldol Reactions. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500160] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Larrañaga O, de Cózar A, Bickelhaupt FM, Zangi R, Cossío FP. Aggregation and cooperative effects in the aldol reactions of lithium enolates. Chemistry 2013; 19:13761-73. [PMID: 23964002 DOI: 10.1002/chem.201301597] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Indexed: 11/11/2022]
Abstract
Density functional theory and Car-Parrinello molecular dynamics simulations have been carried out for model aldol reactions involving aggregates of lithium enolates derived from acetaldehyde and acetone. Formaldehyde and acetone have been used as electrophiles. It is found that the geometries of the enolate aggregates are in general determined by the most favorable arrangements of the point charges within the respective Lin On clusters. The reactivity of the enolates follows the sequence monomer≫dimer>tetramer. In lithium aggregates, the initially formed aldol adducts must rearrange to form more stable structures in which the enolate and alkoxide oxygen atoms are within the respective Lin On clusters. Positive cooperative effects, similar to allosteric effects found in several proteins, are found for the successive aldol reactions in aggregates. The corresponding transition structures show in general sofa geometries.
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Affiliation(s)
- Olatz Larrañaga
- Departamento de Química Orgánica I/, Kimika Organikoa I Saila, Facultad de Química/, Kimika Fakultatea Euskal Herriko Unibertsitatea, UPV/EHU and Donostia International Physics Center (DIPC), 1072, 20018 San Sebastián-Donostia (Spain)
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6
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Walters MJ, Srikannathasan V, McEwan AR, Naismith JH, Fierke CA, Toone EJ. Characterization and crystal structure of Escherichia coli KDPGal aldolase. Bioorg Med Chem 2008; 16:710-20. [PMID: 17981470 PMCID: PMC3326530 DOI: 10.1016/j.bmc.2007.10.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Revised: 10/05/2007] [Accepted: 10/12/2007] [Indexed: 11/29/2022]
Abstract
2-Keto-3-deoxy-6-phosphogluconate (KDPG) and 2-keto-3-deoxy-6-phosphogalactonate (KDPGal) aldolases catalyze an identical reaction differing in substrate specificity in only the configuration of a single stereocenter. However, the proteins show little sequence homology at the amino acid level. Here we investigate the determinants of substrate selectivity of these enzymes. The Escherichia coli KDPGal aldolase gene, cloned into a T7 expression vector and overexpressed in E. coli, catalyzes retro-aldol cleavage of the natural substrate, KDPGal, with values of k(cat)/K(M) and k(cat) of 1.9x10(4)M(-1)s(-1) and 4s(-1), respectively. In the synthetic direction, KDPGal aldolase efficiently catalyzes an aldol addition using a limited number of aldehyde substrates, including d-glyceraldehyde-3-phosphate (natural substrate), d-glyceraldehyde, glycolaldehyde, and 2-pyridinecarboxaldehyde. A preparative scale reaction between 2-pyridinecarboxaldehyde and pyruvate catalyzed by KDPGal aldolase produced the aldol adduct of the R stereochemistry in >99.7% ee, a result complementary to that observed using the related KDPG aldolase. The native crystal structure has been solved to a resolution of 2.4A and displays the same (alpha/beta)(8) topology, as KDPG aldolase. We have also determined a 2.1A structure of a Schiff base complex between the enzyme and its substrate. This model predicts that a single amino acid change, T161 in KDPG aldolase to V154 in KDPGal aldolase, plays an important role in determining the stereochemical course of enzyme catalysis and this prediction was borne out by site-directed mutagenesis studies. However, additional changes in the enzyme sequence are required to prepare an enzyme with both high catalytic efficiency and altered stereochemistry.
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Affiliation(s)
- Matthew J Walters
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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7
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Walters MJ, Srikannathasan V, McEwan AR, Naismith JH, Fierke CA, Toone EJ. Mechanism of the Class I KDPG aldolase. Bioorg Med Chem 2006; 14:3002-10. [PMID: 16403639 PMCID: PMC3315828 DOI: 10.1016/j.bmc.2005.12.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Revised: 12/04/2005] [Accepted: 12/09/2005] [Indexed: 11/17/2022]
Abstract
In vivo, 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase catalyzes the reversible, stereospecific retro-aldol cleavage of KDPG to pyruvate and D-glyceraldehyde-3-phosphate. The enzyme is a lysine-dependent (Class I) aldolase that functions through the intermediacy of a Schiff base. Here, we propose a mechanism for this enzyme based on crystallographic studies of wild-type and mutant aldolases. The three dimensional structure of KDPG aldolase from the thermophile Thermotoga maritima was determined to 1.9A. The structure is the standard alpha/beta barrel observed for all Class I aldolases. At the active site Lys we observe clear density for a pyruvate Schiff base. Density for a sulfate ion bound in a conserved cluster of residues close to the Schiff base is also observed. We have also determined the structure of a mutant of Escherichia coli KDPG aldolase in which the proposed general acid/base catalyst has been removed (E45N). One subunit of the trimer contains density suggesting a trapped pyruvate carbinolamine intermediate. All three subunits contain a phosphate ion bound in a location effectively identical to that of the sulfate ion bound in the T. maritima enzyme. The sulfate and phosphate ions experimentally locate the putative phosphate binding site of the aldolase and, together with the position of the bound pyruvate, facilitate construction of a model for the full-length KDPG substrate complex. The model requires only minimal positional adjustments of the experimentally determined covalent intermediate and bound anion to accommodate full-length substrate. The model identifies the key catalytic residues of the protein and suggests important roles for two observable water molecules. The first water molecule remains bound to the enzyme during the entire catalytic cycle, shuttling protons between the catalytic glutamate and the substrate. The second water molecule arises from dehydration of the carbinolamine and serves as the nucleophilic water during hydrolysis of the enzyme-product Schiff base. The second water molecule may also mediate the base-catalyzed enolization required to form the carbon nucleophile, again bridging to the catalytic glutamate. Many aspects of this mechanism are observed in other Class I aldolases and suggest a mechanistically and, perhaps, evolutionarily related family of aldolases distinct from the N-acetylneuraminate lyase (NAL) family.
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Affiliation(s)
- Matthew J. Walters
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | | | - Andrew R. McEwan
- Centre for Biomolecular Sciences, The University of St. Andrews, St. Andrews KY169ST, UK
| | - James H. Naismith
- Centre for Biomolecular Sciences, The University of St. Andrews, St. Andrews KY169ST, UK
| | - Carol A. Fierke
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48103, USA
| | - Eric J. Toone
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
- Department of Chemistry, Duke University, Durham, NC 27708, USA
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St-Jean M, Lafrance-Vanasse J, Liotard B, Sygusch J. High Resolution Reaction Intermediates of Rabbit Muscle Fructose-1,6-bisphosphate Aldolase. J Biol Chem 2005; 280:27262-70. [PMID: 15870069 DOI: 10.1074/jbc.m502413200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Crystal structures were determined to 1.8 A resolution of the glycolytic enzyme fructose-1,6-bis(phosphate) aldolase trapped in complex with its substrate and a competitive inhibitor, mannitol-1,6-bis(phosphate). The enzyme substrate complex corresponded to the postulated Schiff base intermediate and has reaction geometry consistent with incipient C3-C4 bond cleavage catalyzed Glu-187, which is adjacent by to the Schiff base forming Lys-229. Atom arrangement about the cleaved bond in the reaction intermediate mimics a pericyclic transition state occurring in nonenzymatic aldol condensations. Lys-146 hydrogen-bonds the substrate C4 hydroxyl and assists substrate cleavage by stabilizing the developing negative charge on the C4 hydroxyl during proton abstraction. Mannitol-1,6-bis(phosphate) forms a noncovalent complex in the active site whose binding geometry mimics the covalent carbinolamine precursor. Glu-187 hydrogen-bonds the C2 hydroxyl of the inhibitor in the enzyme complex, substantiating a proton transfer role by Glu-187 in catalyzing the conversion of the carbinolamine intermediate to Schiff base. Modeling of the acyclic substrate configuration into the active site shows Glu-187, in acid form, hydrogen-bonding both substrate C2 carbonyl and C4 hydroxyl, thereby aligning the substrate ketose for nucleophilic attack by Lys-229. The multifunctional role of Glu-187 epitomizes a canonical mechanistic feature conserved in Schiff base-forming aldolases catalyzing carbohydrate metabolism. Trapping of tagatose-1,6-bis(phosphate), a diastereoisomer of fructose 1,6-bis(phosphate), displayed stereospecific discrimination and reduced ketohexose binding specificity. Each ligand induces homologous conformational changes in two adjacent alpha-helical regions that promote phosphate binding in the active site.
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Affiliation(s)
- Miguel St-Jean
- Department of Biochemistry, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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9
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Theodossis A, Walden H, Westwick EJ, Connaris H, Lamble HJ, Hough DW, Danson MJ, Taylor GL. The Structural Basis for Substrate Promiscuity in 2-Keto-3-deoxygluconate Aldolase from the Entner-Doudoroff Pathway in Sulfolobus solfataricus. J Biol Chem 2004; 279:43886-92. [PMID: 15265860 DOI: 10.1074/jbc.m407702200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hyperthermophilic Archaea Sulfolobus solfataricus grows optimally above 80 degrees C and metabolizes glucose by a non-phosphorylative variant of the Entner-Doudoroff pathway. In this pathway glucose dehydrogenase and gluconate dehydratase catalyze the oxidation of glucose to gluconate and the subsequent dehydration of gluconate to D-2-keto-3-deoxygluconate (KDG). KDG aldolase (KDGA) then catalyzes the cleavage of KDG to D-glyceraldehyde and pyruvate. It has recently been shown that all the enzymes of this pathway exhibit a catalytic promiscuity that also enables them to be used for the metabolism of galactose. This phenomenon, known as metabolic pathway promiscuity, depends crucially on the ability of KDGA to cleave KDG and D-2-keto-3-deoxygalactonate (KDGal), in both cases producing pyruvate and D-glyceraldehyde. In turn, the aldolase exhibits a remarkable lack of stereoselectivity in the condensation reaction of pyruvate and D-glyceraldehyde, forming a mixture of KDG and KDGal. We now report the structure of KDGA, determined by multiwavelength anomalous diffraction phasing, and confirm that it is a member of the tetrameric N-acetylneuraminate lyase superfamily of Schiff base-forming aldolases. Furthermore, by soaking crystals of the aldolase at more than 80 degrees C below its temperature activity optimum, we have been able to trap Schiff base complexes of the natural substrates pyruvate, KDG, KDGal, and pyruvate plus D-glyceraldehyde, which have allowed rationalization of the structural basis of promiscuous substrate recognition and catalysis. It is proposed that the active site of the enzyme is rigid to keep its thermostability but incorporates extra functionality to be promiscuous.
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Affiliation(s)
- Alex Theodossis
- Centre for Biomolecular Sciences, University of St. Andrews, North Haugh, Fife KY16 9ST, Scotland
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10
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Lu ZJ, Markham GD. Catalytic Properties of the Archaeal S-Adenosylmethionine Decarboxylase from Methanococcus jannaschii. J Biol Chem 2004; 279:265-73. [PMID: 14573607 DOI: 10.1074/jbc.m308793200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
S-Adenosylmethionine decarboxylase (AdoMetDC) is a pyruvoyl cofactor-dependent enzyme that participates in polyamine biosynthesis. AdoMetDC from the Archaea Methanococcus jannaschii is a prototype for a recently discovered class that is not homologous to the eucaryotic enzymes or to a distinct group of microbial enzymes. M. jannaschii AdoMetDC has a Km of 95 microm and the turnover number (kcat) of 0.0075 s(-1) at pH 7.5 and 22 degrees C. The turnover number increased approximately 38-fold at a more physiological temperature of 80 degrees C. AdoMetDC was inactivated by treatment with the imine reductant NaCNBH3 only in the presence of substrate. Mass spectrometry of the inactivated protein showed modification solely of the pyruvoyl-containing subunit, with a mass increase corresponding to reduction of a Schiff base adduct with decarboxylated AdoMet. The presteady state time course of the AdoMetDC reaction revealed a burst of product formation; thus, a step after CO2 formation is rate-limiting in turnover. Comparable D2O kinetic isotope effects of were seen on the first turnover (1.9) and on kcat/Km (1.6); there was not a significant D2O isotope effect on kcat, suggesting that product release is rate-limiting in turnover. The pH dependence of the steady state rate showed participation of acid and basic groups with pK values of 5.3 and 8.2 for kcat and 6.5 and 8.3 for kcat/Km, respectively. The competitive inhibitor methylglyoxal bis(guanylhydrazone) binds at a single site per (alphabeta) heterodimer. UV spectroscopic studies show that methylglyoxal bis(guanylhydrazone) binds as the dication with a 23 microm dissociation constant. Studies with substrate analogs show a high specificity for AdoMet.
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Affiliation(s)
- Zichun J Lu
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111-2497, USA
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11
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Maurady A, Zdanov A, de Moissac D, Beaudry D, Sygusch J. A conserved glutamate residue exhibits multifunctional catalytic roles in D-fructose-1,6-bisphosphate aldolases. J Biol Chem 2002; 277:9474-83. [PMID: 11779856 DOI: 10.1074/jbc.m107600200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The aldolase catalytic cycle consists of a number of proton transfers that interconvert covalent enzyme intermediates. Glu-187 is a conserved amino acid that is located in the mammalian fructose-1,6-bisphosphate aldolase active site. Its central location, within hydrogen bonding distance of three other conserved active site residues: Lys-146, Glu-189, and Schiff base-forming Lys-229, makes it an ideal candidate for mediating proton transfers. Point mutations, Glu-187--> Gln, Ala, which would inhibit proton transfers significantly, compromise activity. Trapping of enzymatic intermediates in Glu-187 mutants defines a proton transfer role for Glu-187 in substrate cleavage and Schiff base formation. Structural data show that loss of Glu-187 negative charge results in hydrogen bond formation between Lys-146 and Lys-229 consistent with a basic pK(a) for Lys-229 in native enzyme and supporting nucleophilic activation of Lys-229 by Glu-187 during Schiff base formation. The crystal structures also substantiate Glu-187 and Glu-189 as present in ionized form in native enzyme, compatible with their role of catalyzing proton exchange with solvent as indicated from solvent isotope effects. The proton exchange mechanism ensures Glu-187 basicity throughout the catalytic cycle requisite for mediating proton transfer and electrostatic stabilization of ketamine intermediates. Glutamate general base catalysis is a recurrent evolutionary feature of Schiff base0forming aldolases.
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Affiliation(s)
- Amal Maurady
- Department of Biochemistry, University of Montreal, CP 6128, Station Centre Ville, Montréal, Québec H3C 3J7, Canada
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Allard J, Grochulski P, Sygusch J. Covalent intermediate trapped in 2-keto-3-deoxy-6- phosphogluconate (KDPG) aldolase structure at 1.95-A resolution. Proc Natl Acad Sci U S A 2001; 98:3679-84. [PMID: 11274385 PMCID: PMC31111 DOI: 10.1073/pnas.071380898] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2000] [Indexed: 11/18/2022] Open
Abstract
2-Keto-3-deoxy-6-phosphogluconate (KDPG) aldolase catalyzes the reversible cleavage of KDPG to pyruvate and glyceraldehyde-3-phosphate. The enzyme is a class I aldolase whose reaction mechanism involves formation of Schiff base intermediates between Lys-133 and a keto substrate. A covalent adduct was trapped by flash freezing KDPG aldolase crystals soaked with 10 mM pyruvate in acidic conditions at pH 4.6. Structure determination to 1.95-A resolution showed that pyruvate had undergone nucleophilic attack with Lys-133, forming a protonated carbinolamine intermediate, a functional Schiff base precursor, which was stabilized by hydrogen bonding with active site residues. Carbinolamine interaction with Glu-45 indicates general base catalysis of several rate steps. Stereospecific addition is ensured by aromatic interaction of Phe-135 with the pyruvate methyl group. In the native structure, Lys-133 donates all of its hydrogen bonds, indicating the presence of an epsilon-ammonium salt group. Nucleophilic activation is postulated to occur by proton transfer in the monoprotonated zwitterionic pair (Glu-45/Lys-133). Formation of the zwitterionic pair requires prior side chain rearrangement by protonated Lys-133 to displace a water molecule, hydrogen bonded to the zwitterionic residues.
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Affiliation(s)
- J Allard
- Département de Biochimie, Université de Montréal, Montreal, QC, H3C 3J7 Canada
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13
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Page P, Blonski C, Périé J. Origin of the Slow-Binding Inhibition of Aldolase by D-glycero-Tetrulose 1-Phosphate (D-Erythrulose 1-Phosphate) from the Comparison with the Isosteric Phosphonate Analog. European J Org Chem 1999. [DOI: 10.1002/(sici)1099-0690(199911)1999:11<2853::aid-ejoc2853>3.0.co;2-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Page P, Blonski C, Périé J. Interaction of phosphonomethyl analog of dihydroxyacetone phosphate with rabbit muscle aldolase. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1386:59-64. [PMID: 9675245 DOI: 10.1016/s0167-4838(98)00061-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aldolase presents the same binding affinity for dihydroxyacetone phosphate and its phosphonomethyl analog, but the partition coefficient between the intermediates from the Michaelis complex to the eneamine is different. The effects of the structural modification of the triose phosphate substrate on the interaction with rabbit muscle aldolase are discussed in connection with the mechanistic pathway and the three-dimensional structure of the enzyme.
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Affiliation(s)
- P Page
- Groupe de Chimie Organique Biologique, UMR CNRS 5623, Université Paul Sabatier, Bât. II R1, 118 route de Narbonne, 31062 Toulouse Cedex 4, France
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15
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Abstract
Mixed disulphide formation in the presence of oxidized glutathione reversibly inactivates rabbit skeletal muscle aldolase. Inactivation is allosteric, preferentially modifying Cys-72 on the surface of the aldolase homotetramer distant from active-site locations and subunit interfaces. Ion-exchange chromatography fractionates partly inactivated aldolase into three distinct enzymic species: unmodified enzyme, inactive fully modified enzyme corresponding to one thiol reacted per subunit, and inactive singly modified enzyme in which only one thiol has reacted. Acid-precipitable enzymic intermediates formed in the presence of substrate, D-fructose 1,6-bisphosphate, and product, dihydroxyacetone phosphate, indicates that active site binding is unaffected upon modification. The absence of enamine carbanion formation in the presence of substrate but not product is consistent with mixed disulphide formation's blocking -C-C- cleavage and/or subsequent D-glyceraldehyde 3-phosphate release. Inactivation upon single subunit modification and substrate protection against modification denotes that the blocked step is associated with a long-range conformational transition involving highly co-operative subunit behaviour.
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Affiliation(s)
- J Sygusch
- Département de Biochimie/Médecine, Université de Montréal, CP 6128, Station Centre Ville, Montréal, QC, Canada H3C 3J7
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17
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Wong CH, Halcomb RL, Ichikawa Y, Kajimoto T. Enzyme in der organischen Synthese: das Problem der molekularen Erkennung von Kohlenhydraten (Teil 1). Angew Chem Int Ed Engl 1995. [DOI: 10.1002/ange.19951070405] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Gefflaut T, Blonski C, Perie J, Willson M. Class I aldolases: substrate specificity, mechanism, inhibitors and structural aspects. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1995; 63:301-40. [PMID: 8599032 DOI: 10.1016/0079-6107(95)00008-9] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- T Gefflaut
- Groupe de Chimie Organique Biologique, URA CNRS 470 Université Paul Sabatier, Toulouse, France
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Morris AJ, Tolan DR. Lysine-146 of rabbit muscle aldolase is essential for cleavage and condensation of the C3-C4 bond of fructose 1,6-bis(phosphate). Biochemistry 1994; 33:12291-7. [PMID: 7918450 DOI: 10.1021/bi00206a036] [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: 01/27/2023]
Abstract
Lysine-146 of rabbit muscle aldolase (D-fructose-1,6-biphosphate aldolase, EC 4.1.2.13) is absolutely conserved in class I (Schiff base) aldolases and has been implicated previously in catalysis by protein modification. Site-directed mutagenesis was used to change lysine-146 to alanine, glutamine, leucine, or histidine, creating the mutant enzymes K146A, K146Q, K146L, and K146H, respectively. These mutant proteins were expressed at high levels in bacteria and were purified by substrate affinity elution from CM-Sepharose, the same method that is used for the wild-type enzyme. The mutants K146A, K146Q, and K146L had substrate cleavage rates below standard detection levels. Modified cleavage assays indicated that these enzymes were (0.5-2) x 10(6)-fold decreased in the rate of catalysis of fructose 1,6-bis(phosphate) (Fru-1,6-Pa)cleavage. The K146H enzyme, however, was approximately 2000-fold slower than wild type in the rates of both cleavage and condensation of Fru-1,6-P2. In assays for the presence of enzymatic intermediates, all of the mutant enzymes were able to catalyze formation of the carbanion intermediate with dihydroxyacetone phosphate, whereas this intermediate was below the level of detection with Fru-1,6-P2. Single-turnover experiments with these enzymes in excess over radiolabeled Fru-1,6-P2 were used to measure the rates of Schiff base and product formation. The rate of Schiff base formation was decreased in each of the mutant enzymes, yet the magnitude of this decrease was less than the reduction in the respective kcat. These mutations had a much larger effect, however, on the rate of C3-C4 bond breaking, showing that Lys-146 is crucial at this step of the catalytic cycle.
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Affiliation(s)
- A J Morris
- Biology Department, Boston University, Massachusetts 02215
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Henderson I, Garcia-Junceda E, Liu KK, Chen YL, Shen GJ, Wong CH. Cloning, overexpression and isolation of the type II FDP aldolase from E. coli for specificity study and synthetic application. Bioorg Med Chem 1994; 2:837-43. [PMID: 7894977 DOI: 10.1016/s0968-0896(00)82183-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A stable overexpression E. coli strain containing the plasmid pKEN 2 for the production of the Zn(2+)-dependent FDP aldolase from E. coli has been developed. Approximately 14,000 U of the enzyme (specific activity = 23.3 U/mg) can be obtained from 4-L of growth medium. The enzyme was isolated, purified to homogeneity and used for the studies of stability, substrate specificity and metal ion replacement and dissociation. Crystals of the enzyme have been obtained for structural analysis. This E. coli strain was deposited with the American Type Culture Collection (ATCC #77472).
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Affiliation(s)
- I Henderson
- Department of Chemistry, Scripps Research Institute, La Jolla, CA 92037
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Rose IA, Warms JV, Kuo DJ. Concentration and partitioning of intermediates in the fructose bisphosphate aldolase reaction. Comparison of the muscle and liver enzymes. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(19)75840-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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