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Moreno-Paz S, van der Hoek R, Eliana E, Zwartjens P, Gosiewska S, Martins dos Santos VAP, Schmitz J, Suarez-Diez M. Machine Learning-Guided Optimization of p-Coumaric Acid Production in Yeast. ACS Synth Biol 2024; 13:1312-1322. [PMID: 38545878 PMCID: PMC11036487 DOI: 10.1021/acssynbio.4c00035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/07/2024] [Accepted: 03/14/2024] [Indexed: 04/20/2024]
Abstract
Industrial biotechnology uses Design-Build-Test-Learn (DBTL) cycles to accelerate the development of microbial cell factories, required for the transition to a biobased economy. To use them effectively, appropriate connections between the phases of the cycle are crucial. Using p-coumaric acid (pCA) production in Saccharomyces cerevisiae as a case study, we propose the use of one-pot library generation, random screening, targeted sequencing, and machine learning (ML) as links during DBTL cycles. We showed that the robustness and flexibility of the ML models strongly enable pathway optimization and propose feature importance and Shapley additive explanation values as a guide to expand the design space of original libraries. This approach allowed a 68% increased production of pCA within two DBTL cycles, leading to a 0.52 g/L titer and a 0.03 g/g yield on glucose.
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Affiliation(s)
- Sara Moreno-Paz
- Laboratory
of Systems and Synthetic Biology, Wageningen
University & Research, 6708 WE Wageningen, The Netherlands
| | - Rianne van der Hoek
- Department
of Science and Research, dsm-firmenich,
Science & Research, 2600 MA Delft, The
Netherlands
| | - Elif Eliana
- Laboratory
of Systems and Synthetic Biology, Wageningen
University & Research, 6708 WE Wageningen, The Netherlands
| | - Priscilla Zwartjens
- Department
of Science and Research, dsm-firmenich,
Science & Research, 2600 MA Delft, The
Netherlands
| | - Silvia Gosiewska
- Department
of Science and Research, dsm-firmenich,
Science & Research, 2600 MA Delft, The
Netherlands
| | | | - Joep Schmitz
- Department
of Science and Research, dsm-firmenich,
Science & Research, 2600 MA Delft, The
Netherlands
| | - Maria Suarez-Diez
- Laboratory
of Systems and Synthetic Biology, Wageningen
University & Research, 6708 WE Wageningen, The Netherlands
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2
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Shlaifer I, Quashie PK, Kim HY, Turnbull JL. Biochemical characterization of TyrA enzymes from Ignicoccus hospitalis and Haemophilus influenzae: A comparative study of the bifunctional and monofunctional dehydrogenase forms. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1865:312-320. [PMID: 28025081 DOI: 10.1016/j.bbapap.2016.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/23/2016] [Accepted: 12/22/2016] [Indexed: 02/08/2023]
Abstract
Biosynthesis of l-tyrosine (l-Tyr) is directed by the interplay of two enzymes. Chorismate mutase (CM) catalyzes the rearrangement of chorismate to prephenate, which is then converted to hydroxyphenylpyruvate by prephenate dehydrogenase (PD). This work reports the first characterization of the independently expressed PD domain of bifunctional CM-PD from the crenarchaeon Ignicoccus hospitalis and the first functional studies of both full-length CM-PD and the PD domain from the bacterium Haemophilus influenzae. All proteins were hexa-histidine tagged, expressed in Escherichia coli and purified. Expression and purification of I. hospitalis CM-PD generated a degradation product identified as a PD fragment lacking the protein's first 80 residues, Δ80CM-PD. A comparable stable PD domain could also be generated by limited tryptic digestion of this bifunctional enzyme. Thus, Δ80CM-PD constructs were prepared in both organisms. CM-PD and Δ80CM-PD from both organisms were dimeric and displayed the predicted enzymatic activities and thermal stabilities in accord with their hyperthermophilic and mesophilic origins. In contrast with H. influenzae PD activity which was NAD+-specific and displayed >75% inhibition with 50μM l-Tyr, I. hospitalis PD demonstrated dual cofactor specificity with a preference for NADP+ and an insensitivity to l-Tyr. These properties are consistent with a model of the I. hospitalis PD domain based on the previously reported structure of the H. influenzae homolog. Our results highlight the similarities and differences between the archaeal and bacterial TyrA proteins and reveal that the PD activity of both prokaryotes can be successfully mapped to a functionally independent unit.
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Affiliation(s)
- Irina Shlaifer
- Department of Chemistry and Biochemistry and the Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. West, Montréal, Québec H4B 1R6, Canada
| | - Peter Kojo Quashie
- Department of Chemistry and Biochemistry and the Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. West, Montréal, Québec H4B 1R6, Canada
| | - Hyun Young Kim
- Department of Chemistry and Biochemistry and the Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. West, Montréal, Québec H4B 1R6, Canada
| | - Joanne L Turnbull
- Department of Chemistry and Biochemistry and the Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. West, Montréal, Québec H4B 1R6, Canada.
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Shlaifer I, Turnbull JL. Characterization of two key enzymes for aromatic amino acid biosynthesis in symbiotic archaea. Extremophiles 2016; 20:503-14. [DOI: 10.1007/s00792-016-0840-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 05/15/2016] [Indexed: 10/21/2022]
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Development of genetically stable Escherichia coli strains for poly(3-hydroxypropionate) production. PLoS One 2014; 9:e97845. [PMID: 24837211 PMCID: PMC4023983 DOI: 10.1371/journal.pone.0097845] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 04/25/2014] [Indexed: 11/24/2022] Open
Abstract
Poly(3-hydroxypropionate) (P3HP) is a biodegradable and biocompatible thermoplastic. In our previous study, a pathway for P3HP production was constructed in recombinant Esecherichia coli. Seven exogenous genes in P3HP synthesis pathway were carried by two plasmid vectors. However, the P3HP production was severely suppressed by strain instability due to plasmid loss. In this paper, two strategies, chromosomal gene integration and plasmid addiction system (PAS) based on amino acid anabolism, were applied to construct a genetically stable strain. Finally, a combination of those two methods resulted in the best results. The resultant strain carried a portion of P3HP synthesis genes on chromosome and the others on plasmid, and also brought a tyrosine-auxotrophy based PAS. In aerobic fed-batch fermentation, this strain produced 25.7 g/L P3HP from glycerol, about 2.5-time higher than the previous strain with two plasmids. To the best of our knowledge, this is the highest P3HP production from inexpensive carbon sources.
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Ku HK, Do NH, Song JS, Choi S, Yeon SH, Shin MH, Kim KJ, Park SR, Park IY, Kim SK, Lee SJ. Crystal structure of prephenate dehydrogenase from Streptococcus mutans. Int J Biol Macromol 2011; 49:761-6. [PMID: 21798280 DOI: 10.1016/j.ijbiomac.2011.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Revised: 07/11/2011] [Accepted: 07/11/2011] [Indexed: 10/17/2022]
Abstract
Prephenate dehydrogenase (PDH) is a bacterial enzyme that catalyzes conversion of prephenate to 4-hydroxyphenylpyruvate through the oxidative decarboxylation pathway for tyrosine biosynthesis. This enzymatic pathway exists in prokaryotes but is absent in mammals, indicating that it is a potential target for the development of new antibiotics. The crystal structure of PDH from Streptococcus mutans in a complex with NAD(+) shows that the enzyme exists as a homo-dimer, each monomer consisting of two domains, a modified nucleotide binding N-terminal domain and a helical prephenate C-terminal binding domain. The latter is the dimerization domain. A structural comparison of PDHs from mesophilic S. mutans and thermophilic Aquifex aeolicus showed differences in the long loop between β6 and β7, which may be a reason for the high K(m) values of PDH from Streptococcus mutans.
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Affiliation(s)
- Hyung-Keun Ku
- Division of Metrology for Quality of Life, Department of Bio-Analytical Science, University of Science & Technology, Daejeon, Republic of Korea
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Legrand P, Dumas R, Seux M, Rippert P, Ravelli R, Ferrer JL, Matringe M. Biochemical characterization and crystal structure of Synechocystis arogenate dehydrogenase provide insights into catalytic reaction. Structure 2006; 14:767-76. [PMID: 16615917 DOI: 10.1016/j.str.2006.01.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 01/10/2006] [Accepted: 01/17/2006] [Indexed: 10/24/2022]
Abstract
The extreme diversity in substrate specificity, and in the regulation mechanism of arogenate/prephenate dehydrogenase enzymes in nature, makes a comparative structural study of these enzymes of great interest. We report here on the biochemical and structural characterization of arogenate dehydrogenase from Synechocystis sp. (TyrAsy). This work paves the way for the understanding of the structural determinants leading to diversity in substrate specificity, and of the regulation mechanisms of arogenate/prephenate dehydrogenases. The overall structure of TyrAsy in complex with NADP was refined to 1.6 A. The asymmetric unit contains two TyrAsy homodimers, with each monomer consisting of a nucleotide binding N-terminal domain and a particularly unique alpha-helical C-terminal dimerization domain. The substrate arogenate was modeled into the active site. The model of the ternary complex enzyme-NADP-arogenate nicely reveals at the atomic level the concerted mechanism of the arogenate/prephenate dehydrogenase reaction.
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Affiliation(s)
- Pierre Legrand
- Institut de Biologie Structurale Jean-Pierre Ebel, Centre National de la Recherche Scientifique, Université Joseph Fourier, Laboratoire de Cristallographie et Cristallogenèse des Protéines/Groupe Synchrotron, 38027 Grenoble cedex 1, France
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Bonvin J, Aponte RA, Marcantonio M, Singh S, Christendat D, Turnbull JL. Biochemical characterization of prephenate dehydrogenase from the hyperthermophilic bacterium Aquifex aeolicus. Protein Sci 2006; 15:1417-32. [PMID: 16731976 PMCID: PMC2265095 DOI: 10.1110/ps.051942206] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 03/01/2006] [Accepted: 03/01/2006] [Indexed: 10/24/2022]
Abstract
A monofunctional prephenate dehydrogenase (PD) from Aquifex aeolicus was expressed as a His-tagged protein in Escherichia coli and was purified by nickel affinity chromatography allowing the first biochemical and biophysical characterization of a thermostable PD. A. aeolicus PD is susceptible to proteolysis. In this report, the properties of the full-length PD are compared with one of these products, an N-terminally truncated protein variant (Delta19PD) also expressed recombinantly in E. coli. Both forms are dimeric and show maximum activity at 95 degrees C or higher. Delta19PD is more sensitive to temperature effects yielding a half-life of 55 min at 95 degrees C versus 2 h for PD, and values of kcat and Km for prephenate, which are twice those determined for PD at 80 degrees C. Low concentrations of guanidine-HCl activate enzyme activity, but at higher concentrations activity is lost concomitant with a multi-state pathway of denaturation that proceeds through unfolding of the dimer, oligomerization, then unfolding of monomers. Measurements of steady-state fluorescence intensity and its quenching by acrylamide in the presence of Gdn-HCl suggest that, of the two tryptophan residues per monomer, one is buried in a hydrophobic pocket and does not become solvent exposed until the protein unfolds, while the less buried tryptophan is at the active site. Tyrosine is a feedback inhibitor of PD activity over a wide temperature range and enhances the cooperativity between subunits in the binding of prephenate. Properties of this thermostable PD are compared and contrasted with those of E. coli chorismate mutase-prephenate dehydrogenase and other mesophilic homologs.
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Affiliation(s)
- Julie Bonvin
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec H4B 1R6, Canada
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Rippert P, Matringe M. Purification and kinetic analysis of the two recombinant arogenate dehydrogenase isoforms of Arabidopsis thaliana. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:4753-61. [PMID: 12354106 DOI: 10.1046/j.1432-1033.2002.03172.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study reports the first purification and kinetic characterization of two plant arogenate dehydrogenases (EC 1.3.1.43), an enzyme that catalyses the oxidative decarboxylation of arogenate into tyrosine in presence of NADP. The two Arabidopsis thaliana arogenate dehydrogenases TyrAAT1 and TyrAAT2 were overproduced in Escherichia coli and purified to homogeneity. Biochemical comparison of the two forms revealed that at low substrate concentration TyrAAT1 is four times more efficient in catalyzing the arogenate dehydrogenase reaction than TyrAAT2. Moreover, TyrAAT2 presents a weak prephenate dehydrogenase activity whereas TyrAAT1 does not. The mechanism of the dehydrogenase reaction catalyzed by these two forms has been investigated using steady-state kinetics. For both enzymes, steady-state velocity patterns are consistent with a rapid equilibrium, random mechanism in which two dead-end complexes, E-NADPH-arogenate and E-NADP-tyrosine, are formed.
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Affiliation(s)
- Pascal Rippert
- Laboratoire Mixte CNRS/INRA/Bayer CropScience (UMR 1932), Lyon, France
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9
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Romero R, Roberts M, Phillipson J. Chorismate mutase in microorganisms and plants. PHYTOCHEMISTRY 1995; 40:1015-1025. [PMID: 0 DOI: 10.1016/0031-9422(95)00408-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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10
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Turnbull J, Cleland WW, Morrison JF. pH dependency of the reactions catalyzed by chorismate mutase-prephenate dehydrogenase from Escherichia coli. Biochemistry 1991; 30:7777-82. [PMID: 1868055 DOI: 10.1021/bi00245a016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The variation with pH of the kinetic parameters associated with the mutase and dehydrogenase reactions catalyzed by chorismate mutase-prephenate dehydrogenase has been determined with the aim of elucidating the role that ionizing amino acid residues play in binding and catalysis. The pH dependency of log V for the dehydrogenase reaction shows that the enzyme possesses a single ionizing group with a pK value of 6.5 that must be unprotonated for catalysis. This same group is observed in the V/Kprephenate, as well as in the V/KNAD, profile. The V/Kprephenate profile exhibits a second ionizing residue with a pK value of 8.4 that must be protonated for the binding of prephenate to the enzyme. For the mutase reaction, the V/Kchorismate profile indicates the presence of three ionizing residues at the active site. Two of these residues, with similar pK values of about 7, must be protonated, while the third, with a pK value of 6.3, must be unprotonated. It can be concluded that all three groups are concerned with the binding of chorismate to the enzyme since the maximum velocity of the mutase reaction is essentially independent of pH. This conclusion is confirmed by the finding that the Ki profile for the competitive inhibitor, (3-endo,8-exo)-8-hydroxy-2-oxabicyclo[3.3]non-6-ene-3,5-dicarboxylic acid, shows the same three ionizing groups as observed in the V/Kchorismate profile. By contrast, the Ki profile for carboxyethyldihydrobenzoate shows only one residue, with a pK value of 7.3, that must be protonated for binding of the inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Turnbull
- Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Australian National University, Canberra, ACT
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11
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Affiliation(s)
- R Bentley
- Department of Chemistry, University of Sheffield, U.K
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12
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13
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Clarke T, Stewart JD, Ganem B. Stereoselective fragmentation of a tricyclic diester leading to a potent chorismate mutase transition state inhibitor. Tetrahedron Lett 1987. [DOI: 10.1016/s0040-4039(01)91345-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Christopherson RI. Chorismate mutase-prephenate dehydrogenase from Escherichia coli: cooperative effects and inhibition by L-tyrosine. Arch Biochem Biophys 1985; 240:646-54. [PMID: 3896148 DOI: 10.1016/0003-9861(85)90072-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effects of a variety of structural analogs of L-tyrosine on the mutase and dehydrogenase activities of hydroxyphenylpyruvate synthase have been investigated. From these studies it is concluded that the alpha-NH3+ alpha-COO-, and the 4-OH groups are essential for binding of L-tyrosine as an inhibitor of the dehydrogenase and that the L configuration is also essential. Dixon plots for inhibition of the dehydrogenase activity by some of these analogs were nonlinear and could be described by a velocity equation that is the ratio of quadratic polynomials (a 2/1 function). Dixon plots for inhibition of the mutase by prephenate at low concentrations of chorismate could also be described by a 2/1 function, but at low concentrations of prephenate chorismate acts as an apparent hyperbolic activator of the dehydrogenase activity. Up to concentrations of 300 microM, L-tyrosine activates the mutase but acts as a potent inhibitor of the dehydrogenase. Such data for the dehydrogenase could not be described by a 2/1 function in 1/[prephenate] but could be fitted to the Hill equation with increasing concentrations of L-tyrosine in the presence of 1.0 mM NAD yielding increasing values for the Hill number (n): in the absence of L-tyrosine, n = 1.6 +/- 0.1; at 150 microM L-tyrosine, n = 2.1 +/- 0.1; at 300 microM L-tyrosine, n = 2.3 +/- 0.4. L-Tyrosine bears a close structural resemblance to both prephenate and hydroxyphenylpyruvate, and evidence is presented which is consistent with L-tyrosine acting as a competitive inhibitor with respect to prephenate of the dehydrogenase.
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Mayer E, Waldner-Sander S, Keller B, Keller E, Lingens F. Purification of arogenate dehydrogenase from Phenylobacterium immobile. FEBS Lett 1985; 179:208-12. [PMID: 3967752 DOI: 10.1016/0014-5793(85)80519-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Phenylobacterium immobile, a bacterium which is able to degrade the herbicide chloridazon, utilizes for L-tyrosine synthesis arogenate as an obligatory intermediate which is converted in the final biosynthetic step by a dehydrogenase to tyrosine. This enzyme, the arogenate dehydrogenase, has been purified for the first time in a 5-step procedure to homogeneity as confirmed by electrophoresis. The Mr of the enzyme that consists of two identical subunits amounts to 69000 as established by gel electrophoresis after cross-linking the enzyme with dimethylsuberimidate. The Km values were 0.09 mM for arogenate and 0.02 mM for NAD+. The enzyme has a high specificity with respect to its substrate arogenate.
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16
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Hudson GS, Davidson BE. Nucleotide sequence and transcription of the phenylalanine and tyrosine operons of Escherichia coli K12. J Mol Biol 1984; 180:1023-51. [PMID: 6396419 DOI: 10.1016/0022-2836(84)90269-9] [Citation(s) in RCA: 147] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A 4509 base-pair DNA fragment containing the phenylalanine and tyrosine operons of Escherichia coli K12 has been sequenced, and the pattern of transcription of these operons examined by S1 mapping, primer extension and galK fusion analyses. The phe operon consists of promoter, operator, leader region containing the phe attenuator and the pheA gene encoding chorismate mutase/prephenate dehydratase. The tyr operon consists of promoter, operator, a short leader region without an attenuator, and two structural genes aroF and tyrA encoding the tyrosine-sensitive isoenzyme of 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP) synthetase and chorismate mutase/prephenate dehydrogenase, respectively. A bidirectional transcription terminator occurs between the two operons. The predicted amino acid sequences of chorismate mutase/prephenate dehydrogenase and chorismate mutase/prephenate dehydratase are homologous at their N termini, while the tyrosine-sensitive isoenzyme of DAHP synthetase is closely homologous to the phenylalanine-sensitive isoenzyme encoded by aroG.
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17
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Addadi L, Jaffe EK, Knowles JR. Secondary tritium isotope effects as probes of the enzymic and nonenzymic conversion of chorismate to prephenate. Biochemistry 1983; 22:4494-501. [PMID: 6354259 DOI: 10.1021/bi00288a022] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
To obtain information about the degree of concert of both the nonenzymic and the enzyme-catalyzed rearrangement of chorismate to prephenate, we have determined the secondary tritium isotope effects at the bond-making position (C-9) and the bond-breaking position (C-5) of chorismate. The isotope effects were determined by the competitive method, using either [5-3H,7-14C )chorismate or [9-3H,7-14C]chorismate as the substrate. In the nonenzymic reaction (pH 7.5, 60 degrees C), KH/kT is 1.149 +/- 0.012 for bond breaking (C-9) and 0.992 +/- 0.012 for bond making (C-5). This indicates an asymmetric transition state in which the new bond is hardly, if at all, formed, while the bond between C-5 and oxygen is substantially broken. In the enzymic reaction (pH 7.5, 30 degrees C), the values of kH/kT in both positions are unity within experimental error. It is most likely that the isotope effects are suppressed in the enzymic process and that the rate-limiting transition state occurs before the rearrangement itself. The kinetically significant transition state presumably involves either the binding step of the small equilibrium proportion of the axial conformer of the substrate or an isomerization of enzyme-bound chorismate from the more stable conformer in which the carboxyvinyloxy group is equatorial to that in which this group is axial. Rearrangement would then proceed relatively rapidly from the higher energy axial conformer.
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18
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Armarego WL, Waring P. Inhibition of human brain dihydropteridine reductase [E.C.1.6.99.10] by the oxidation products of catecholamines, the aminochromes. Biochem Biophys Res Commun 1983; 113:895-9. [PMID: 6870900 DOI: 10.1016/0006-291x(83)91083-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Dihydropteridine reductase from human brain has been purified to homogeneity using a naphthaquinone affinity column followed by chromatography on a 5'-AMP-Sepharose column. Contrary to earlier findings, dopamine (I), noradrenaline (II), and adrenaline (III) do not inhibit this enzyme at concentrations below 200 microM, but their oxidation products, the respective aminochromes (IV, V and VI) are inhibitors. The Ki values for adrenochrome (VI) are reported.
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Christopherson RI, Heyde E, Morrison JF. Chorismate mutase-prephenate dehydrogenase from Escherichia coli: spatial relationship of the mutase and dehydrogenase sites. Biochemistry 1983; 22:1650-6. [PMID: 6342665 DOI: 10.1021/bi00276a020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The inhibition of the bifunctional enzyme chorismate mutase-prephenate dehydrogenase (4-hydroxyphenylpyruvate synthase) by substrate analogues has been investigated at pH 6.0 with the aim of elucidating the spatial relationship that exists between the sites at which each reaction occurs. Several chorismate and adamantane derivatives, as well as 2-hydroxyphenyl acetate and diethyl malonate, act as linear competitive inhibitors with respect to chorismate in the mutase reaction and with respect to chorismate in the mutase reaction and with respect to prephenate in the dehydrogenase reaction. The similarity of the dissociation constants for the interaction of these compounds with the free enzyme, as determined from the mutase and dehydrogenase reactions, indicates that the reaction of these inhibitors at a single site prevents the binding of both chorismate and prephenate. However, not all the groups on the enzyme, which are responsible for the binding of these two substrates, can be identical. At lower concentrations, citrate or malonate prevents reaction of the enzyme with prephenate, but not with chorismate. Nevertheless, the combining sites for chorismate and prephenate are in such close proximity that the diethyl derivative of malonate prevents the binding of both substrates. The results lead to the proposal that the sites at which chorismate and prephenate react on hydroxyphenylpyruvate synthase share common features and can be considered to overlap.
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Hudson GS, Howlett GJ, Davidson BE. The binding of tyrosine and NAD+ to chorismate mutase/prephenate dehydrogenase from Escherichia coli K12 and the effects of these ligands on the activity and self-association of the enzyme. Analysis in terms of a model. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32838-2] [Citation(s) in RCA: 25] [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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21
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Bhosale SB, Rood JI, Sneddon MK, Morrison JF. Production of chorismate mutase-prephenate dehydrogenase by a strain of Escherichia coli carrying a multicopy, tyrA plasmid. Isolation and properties of the enzyme. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 717:6-11. [PMID: 7049251 DOI: 10.1016/0304-4165(82)90372-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A multicopy plasmid that contains the tyrosine operon has been used to transform strains of Escherichia coli K-12. The resultant strains yielded levels of chorismate mutase-prephenate dehydrogenase that were up to 5000-fold higher than that given by the parent strain and about 6-fold higher than that given by a tyrR strain. The production of enzyme fell when tetracycline was omitted from the growth medium because of the loss of the plasmid. The bifunctional enzyme was isolated in good yield by a simple purification procedure and shown to possess properties identical to those exhibited by the enzyme from a tyrR strain.
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Sampathkumar P, Morrison JF. Chorismate mutase-prephenate dehydrogenase from Escherichia coli. Kinetic mechanism of the prephenate dehydrogenase reaction. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 702:212-9. [PMID: 7044425 DOI: 10.1016/0167-4838(82)90505-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The mechanism of the dehydrogenase reaction catalyzed by chorismate mutase-prephenate dehydrogenase (chorismate pyruvatemutase, EC 5.4.99.5-prephenate:NAD+ oxidoreductase (decarboxylating), EC 1.3.1.12) has been investigated using steady-state kinetic techniques. The steady-state velocity pattern in the absence of products as well as product and dead-end inhibition patterns are consistent with a random mechanism in which two dead-end complexes, E-NADH-prephenate and E-NAD-hydroxyphenylpyruvate, are formed, and in which all steps are in rapid equilibrium except that concerned with the interconversion of central ternary complexes. Values have been determined for the maximum velocity of the reaction as well as for the kinetic parameters associated with the combination of substrates, products and the dead-end inhibitor, AMP, with various enzyme forms. The results indicate that when albumin is present in the reaction mixture, the presence of one substrate on the enzyme does not affect the combination of the second substrate. On the other hand, the binding of 4-hydroxyphenylpyruvate is enhanced by the presence of NAD and the binding of NADH is enhanced by the presence of prephenate on the enzyme. These results contrast with the finding that the inhibitory analogue, AMP, binds more strongly to the free enzyme than to the E-prephenate complex.
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