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Kropp C, Bruckmann A, Babinger P. Controlling Enzymatic Activity by Modulating the Oligomerization State via Chemical Rescue and Optical Control. Chembiochem 2021; 23:e202100490. [PMID: 34633135 PMCID: PMC9298306 DOI: 10.1002/cbic.202100490] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/08/2021] [Indexed: 12/22/2022]
Abstract
Selective switching of enzymatic activity has been a longstanding goal in synthetic biology. Drastic changes in activity upon mutational manipulation of the oligomerization state of enzymes have frequently been reported in the literature, but scarcely exploited for switching. Using geranylgeranylglyceryl phosphate synthase as a model, we demonstrate that catalytic activity can be efficiently controlled by exogenous modulation of the association state. We introduced a lysine‐to‐cysteine mutation, leading to the breakdown of the active hexamer into dimers with impaired catalytic efficiency. Addition of bromoethylamine chemically rescued the enzyme by restoring hexamerization and activity. As an alternative method, we incorporated the photosensitive unnatural amino acid o‐nitrobenzyl‐O‐tyrosine (ONBY) into the hexamerization interface. This again led to inactive dimers, but the hexameric state and activity could be recovered by UV‐light induced cleavage of ONBY. For both approaches, we obtained switching factors greater than 350‐fold, which compares favorably with previously reported activity changes that were caused by site‐directed mutagenesis.
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Affiliation(s)
- Cosimo Kropp
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Astrid Bruckmann
- Institute of Biochemistry, Genetics and Microbiology, Regensburg Center for Biochemistry, University of Regensburg, 93040, Regensburg, Germany
| | - Patrick Babinger
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040, Regensburg, Germany
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2
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Hubrich F, Müller M, Andexer JN. Chorismate- and isochorismate converting enzymes: versatile catalysts acting on an important metabolic node. Chem Commun (Camb) 2021; 57:2441-2463. [PMID: 33605953 DOI: 10.1039/d0cc08078k] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chorismate and isochorismate represent an important branching point connecting primary and secondary metabolism in bacteria, fungi, archaea and plants. Chorismate- and isochorismate-converting enzymes are potential targets for new bioactive compounds, as well as valuable biocatalysts for the in vivo and in vitro synthesis of fine chemicals. The diversity of the products of chorismate- and isochorismate-converting enzymes is reflected in the enzymatic three-dimensional structures and molecular mechanisms. Due to the high reactivity of chorismate and its derivatives, these enzymes have evolved to be accurately tailored to their respective reaction; at the same time, many of them exhibit a fascinating flexibility regarding side reactions and acceptance of alternative substrates. Here, we give an overview of the different (sub)families of chorismate- and isochorismate-converting enzymes, their molecular mechanisms, and three-dimensional structures. In addition, we highlight important results of mutagenetic approaches that generate a broader understanding of the influence of distinct active site residues for product formation and the conversion of one subfamily into another. Based on this, we discuss to what extent the recent advances in the field might influence the general mechanistic understanding of chorismate- and isochorismate-converting enzymes. Recent discoveries of new chorismate-derived products and pathways, as well as biocatalytic conversions of non-physiological substrates, highlight how this vast field is expected to continue developing in the future.
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Affiliation(s)
- Florian Hubrich
- ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
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3
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Cristobal JR, Reyes AC, Richard JP. The Organization of Active Site Side Chains of Glycerol-3-phosphate Dehydrogenase Promotes Efficient Enzyme Catalysis and Rescue of Variant Enzymes. Biochemistry 2020; 59:1582-1591. [PMID: 32250105 PMCID: PMC7207223 DOI: 10.1021/acs.biochem.0c00175] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
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A comparison of the
values of kcat/Km for reduction of dihydroxyacetone phosphate
(DHAP) by NADH catalyzed by wild type and K120A/R269A variant glycerol-3-phosphate
dehydrogenase from human liver (hlGPDH) shows that
the transition state for enzyme-catalyzed hydride transfer is stabilized
by 12.0 kcal/mol by interactions with the cationic K120 and R269 side
chains. The transition state for the K120A/R269A variant-catalyzed
reduction of DHAP is stabilized by 1.0 and 3.8 kcal/mol for reactions
in the presence of 1.0 M EtNH3+ and guanidinium
cation (Gua+), respectively, and by 7.5 kcal/mol for reactions
in the presence of a mixture of each cation at 1.0 M, so that the
transition state stabilization by the ternary E·EtNH3+·Gua+ complex is 2.8 kcal/mol greater
than the sum of stabilization by the respective binary complexes.
This shows that there is cooperativity between the paired activators
in transition state stabilization. The effective molarities (EMs)
of ∼50 M determined for the K120A and R269A side chains are
≪106 M, the EM for entropically controlled reactions.
The unusually efficient rescue of the activity of hlGPDH-catalyzed reactions by the HPi/Gua+ pair
and by the Gua+/EtNH3+ activator
pair is due to stabilizing interactions between the protein and the
activator pieces that organize the K120 and R269 side chains at the
active site. This “preorganization” of side chains promotes
effective catalysis by hlGPDH and many other enzymes.
The role of the highly conserved network of side chains, which include
Q295, R269, N270, N205, T264, K204, D260, and K120, in catalysis is
discussed.
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Affiliation(s)
- Judith R Cristobal
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States
| | - Archie C Reyes
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States
| | - John P Richard
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States
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Nagar M, Kumar H, Bearne SL. A platform for chemical modification of mandelate racemase: characterization of the C92S/C264S and γ-thialysine 166 variants. Protein Eng Des Sel 2018; 31:135-145. [PMID: 29850884 DOI: 10.1093/protein/gzy011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/03/2018] [Indexed: 11/14/2022] Open
Abstract
Mandelate racemase (MR) serves as a paradigm for our understanding of enzyme-catalyzed deprotonation of a carbon acid substrate. To facilitate structure-function studies on MR using non-natural amino acid substitutions, we engineered the Cys92Ser/Cys264Ser variant (dmMR) as a platform for introducing Cys residues at specific locations for subsequent covalent modification. While the highly reactive thiol of Cys furnishes a site for chemical modification, site-specificity requires that other Cys residues be non-reactive or replaced by a non-reactive amino acid, especially if chemical modification is conducted under denaturing conditions. The catalytic efficiency of dmMR is reduced only ~2-fold relative to wild-type MR, making dmMR a viable platform for the site-specific introduction of Cys. As an example, the inactive Lys166Cys variant of dmMR was treated with ethylenimine under denaturing conditions to replace the Brønsted acid-base catalyst Lys 166 with the non-natural amino acid γ-thialysine. Comparison of the pH-activity profiles of dmMR and the active γ-thialysine variant revealed a reduction in the pKa for the side chain amino group of ~0.4 units for the latter variant. Unlike wild-type MR for which diffusion is partially rate-limiting, dmMR and the γ-thialysine variant showed no dependence on the solvent viscosity suggesting that the chemical step is fully rate-limiting.
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Affiliation(s)
- Mitesh Nagar
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Himank Kumar
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Stephen L Bearne
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada.,Department of Chemistry, Dalhousie University, Halifax, NS, Canada
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Reyes AC, Amyes TL, Richard JP. Enzyme Architecture: Self-Assembly of Enzyme and Substrate Pieces of Glycerol-3-Phosphate Dehydrogenase into a Robust Catalyst of Hydride Transfer. J Am Chem Soc 2016; 138:15251-15259. [PMID: 27792325 PMCID: PMC5291162 DOI: 10.1021/jacs.6b09936] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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The stabilization of the transition
state for hlGPDH-catalyzed reduction of DHAP due
to the action of the phosphodianion
of DHAP and the cationic side chain of R269 is between 12.4 and 17
kcal/mol. The R269A mutation of glycerol-3-phosphate dehydrogenase
(hlGPDH) results in a 9.1 kcal/mol destabilization
of the transition state for enzyme-catalyzed reduction of dihydroxyacetone
phosphate (DHAP) by NADH, and there is a 6.7 kcal/mol stabilization of this transition state by 1.0 M guanidine cation (Gua+) [J. Am. Chem. Soc.2015, 137, 5312–5315]. The R269A mutant shows no detectable
activity toward reduction of glycolaldehyde (GA), or activation of
this reaction by 30 mM HPO32–. We report
the unprecedented self-assembly of R269A hlGPDH,
dianions (X2– = FPO32–, HPO32–, or SO42–), Gua+ and GA into a functioning catalyst of the reduction
of GA, and fourth-order reaction rate constants kcat/KGAKXKGua. The linear logarithmic correlation
(slope = 1.0) between values of kcat/KGAKX for dianion
activation of wildtype hlGPDH-catalyzed reduction
of GA and kcat/KGAKXKGua shows that the electrostatic interaction between exogenous dianions
and the side chain of R269 is not significantly perturbed by cutting hlGPDH into R269A and Gua+ pieces. The advantage
for connection of hlGPDH (R269A mutant + Gua+) and substrate pieces (GA + HPi) pieces, (ΔGS‡)HPi+E+Gua = 5.6 kcal/mol, is nearly equal to the sum
of the advantage to connection of the substrate pieces, (ΔGS‡)GA+HPi = 3.3 kcal/mol, for wildtype hlGPDH-catalyzed reaction of GA + HPi, and for connection
of the enzyme pieces, (ΔGS‡)E+Gua = 2.4
kcal/mol, for Gua+ activation of the R269A hlGPDH-catalyzed reaction of DHAP.
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Affiliation(s)
- Archie C Reyes
- Department of Chemistry, University at Buffalo, SUNY , Buffalo, New York 14260-3000, United States
| | - Tina L Amyes
- Department of Chemistry, University at Buffalo, SUNY , Buffalo, New York 14260-3000, United States
| | - John P Richard
- Department of Chemistry, University at Buffalo, SUNY , Buffalo, New York 14260-3000, United States
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Reyes AC, Koudelka AP, Amyes TL, Richard JP. Enzyme architecture: optimization of transition state stabilization from a cation-phosphodianion pair. J Am Chem Soc 2015; 137:5312-5. [PMID: 25884759 PMCID: PMC4416717 DOI: 10.1021/jacs.5b02202] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
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The
side chain cation of R269 lies at the surface of l-glycerol
3-phosphate dehydrogenase (GPDH) and forms an ion pair
to the phosphodianion of substrate dihydroxyacetone phosphate (DHAP),
which is buried at the nonpolar protein interior. The R269A mutation
of GPDH results in a 110-fold increase in Km (2.8 kcal/mol effect) and a 41 000-fold decrease in kcat (6.3 kcal/mol effect), which corresponds
to a 9.1 kcal/mol destabilization of the transition state for GPDH-catalyzed
reduction of DHAP by NADH. There is a 6.7 kcal/mol stabilization of
the transition state for the R269A mutant GPDH-catalyzed reaction
by 1.0 M guanidinium ion, and the transition state for the reaction
of the substrate pieces is stabilized by an additional 2.4 kcal/mol
by their covalent attachment at wildtype GPDH. These results provide
strong support for the proposal that GPDH invests the 11 kcal/mol
intrinsic phosphodianion binding energy of DHAP in trapping the substrate
at a nonpolar active site, where strong electrostatic interactions
are favored, and obtains a 9 kcal/mol return from stabilizing interactions
between the side chain cation and transition state trianion. We propose
a wide propagation for the catalytic motif examined in this work,
which enables strong transition state stabilization from enzyme–phosphodianion
pairs.
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Affiliation(s)
- Archie C Reyes
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States
| | - Astrid P Koudelka
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States
| | - Tina L Amyes
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States
| | - John P Richard
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States
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Zhu L, Zhou L, Cui W, Liu Z, Zhou Z. Mechanism-based site-directed mutagenesis to shift the optimum pH of the phenylalanine ammonia-lyase from Rhodotorula glutinis JN-1. ACTA ACUST UNITED AC 2014. [PMID: 28626644 PMCID: PMC5466100 DOI: 10.1016/j.btre.2014.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phenylalanine ammonia-lyase (RgPAL) from Rhodotorula glutinis JN-1 stereoselectively catalyzes the conversion of the l-phenylalanine into trans-cinnamic acid and ammonia, and was used in chiral resolution of dl-phenylalanine to produce the d-phenylalanine under acidic condition. However, the optimum pH of RgPAL is 9 and the RgPAL exhibits low catalytic efficiency at acidic side. Therefore, a mutant RgPAL with a lower optimum pH is expected. Based on catalytic mechanism and structure analysis, we constructed a mutant RgPAL-Q137E by site-directed mutagenesis, and found that this mutant had an extended optimum pH 7-9 with activity of 1.8-fold higher than that of the wild type at pH 7. As revealed by Friedel-Crafts-type mechanism of RgPAL, the improvement of the RgPAL-Q137E might be due to the negative charge of Glu137 which could stabilize the intermediate transition states through electrostatic interaction. The RgPAL-Q137E mutant was used to resolve the racemic dl-phenylalanine, and the conversion rate and the eeD value of d-phenylalanine using RgPAL-Q137E at pH 7 were increased by 29% and 48%, and achieved 93% and 86%, respectively. This work provides an effective strategy to shift the optimum pH which is favorable to further applications of RgPAL.
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Affiliation(s)
- Longbao Zhu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Li Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Wenjing Cui
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhongmei Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhemin Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
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Meneely KM, Luo Q, Lamb AL. Redesign of MST enzymes to target lyase activity instead promotes mutase and dehydratase activities. Arch Biochem Biophys 2013; 539:70-80. [PMID: 24055536 DOI: 10.1016/j.abb.2013.09.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/10/2013] [Accepted: 09/11/2013] [Indexed: 11/20/2022]
Abstract
The isochorismate and salicylate synthases are members of the MST family of enzymes. The isochorismate synthases establish an equilibrium for the conversion chorismate to isochorismate and the reverse reaction. The salicylate synthases convert chorismate to salicylate with an isochorismate intermediate; therefore, the salicylate synthases perform isochorismate synthase and isochorismate-pyruvate lyase activities sequentially. While the active site residues are highly conserved, there are two sites that show trends for lyase-activity and lyase-deficiency. Using steady state kinetics and HPLC progress curves, we tested the "interchange" hypothesis that interconversion of the amino acids at these sites would promote lyase activity in the isochorismate synthases and remove lyase activity from the salicylate synthases. An alternative, "permute" hypothesis, that chorismate-utilizing enzymes are designed to permute the substrate into a variety of products and tampering with the active site may lead to identification of adventitious activities, is tested by more sensitive NMR time course experiments. The latter hypothesis held true. The variant enzymes predominantly catalyzed chorismate mutase-prephenate dehydratase activities, sequentially generating prephenate and phenylpyruvate, augmenting previously debated (mutase) or undocumented (dehydratase) adventitious activities.
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Affiliation(s)
- Kathleen M Meneely
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, United States
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