1
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Hegazy R, Richard JP. Triosephosphate Isomerase: The Crippling Effect of the P168A/I172A Substitution at the Heart of an Enzyme Active Site. Biochemistry 2023; 62:2916-2927. [PMID: 37768194 PMCID: PMC10586322 DOI: 10.1021/acs.biochem.3c00414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/01/2023] [Indexed: 09/29/2023]
Abstract
The P168 and I172 side chains sit at the heart of the active site of triosephosphate isomerase (TIM) and play important roles in the catalysis of the isomerization reaction. The phosphodianion of substrate glyceraldehyde 3-phosphate (GAP) drives a conformational change at the TIM that creates a steric interaction with the P168 side chain that is relieved by the movement of P168 that carries the basic E167 side chain into a clamp that consists of the hydrophobic I172 and L232 side chains. The P168A/I172A substitution at TIM from Trypanosoma brucei brucei (TbbTIM) causes a large 120,000-fold decrease in kcat for isomerization of GAP that eliminates most of the difference in the reactivity of TIM compared to the small amine base quinuclidinone for deprotonation of catalyst-bound GAP. The I172A substitution causes a > 2-unit decrease in the pKa of the E167 carboxylic acid in a complex to the intermediate analog PGA, but the P168A substitution at the I172A variant has no further effect on this pKa. The P168A/I172A substitutions cause a 5-fold decrease in Km for the isomerization of GAP from a 0.9 kcal/mol stabilization of the substrate Michaelis complexes. The results show that the P168 and I172 side chains play a dual role in destabilizing the ground-state Michaelis complex to GAP and in promoting stabilization of the transition state for substrate isomerization. This is consistent with an important role for these side chains in an induced fit reaction mechanism [Richard, J. P. (2022) Enabling Role of Ligand-Driven Conformational Changes in Enzyme Evolution. Biochemistry 61, 1533-1542].
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Affiliation(s)
- Rania Hegazy
- 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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2
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Wang CN, Qiu S, Fan FF, Lyu CJ, Hu S, Zhao WR, Mei JQ, Mei LH, Huang J. Enhancing the organic solvent resistance of ω-amine transaminase for enantioselective synthesis of (R)-(+)-1(1-naphthyl)-ethylamine. Biotechnol J 2023; 18:e2300120. [PMID: 37337619 DOI: 10.1002/biot.202300120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/28/2023] [Accepted: 06/14/2023] [Indexed: 06/21/2023]
Abstract
BACKGROUND Biocatalysis in high-concentration organic solvents has been applied to produce various industrial products with many advantages. However, using enzymes in organic solvents often suffers from inactivation or decreased catalytic activity and stability. An R-selective ω-amine transaminase from Aspergillus terreus (AtATA) exhibited activity toward 1-acetylnaphthalene. However, AtATA displayed unsatisfactory organic solvent resistance, which is required to enhance the solubility of the hydrophobic substrate 1-acetylnaphthalene. So, improving the tolerance of enzymes in organic solvents is essential. MAIN METHODS AND RESULTS The method of regional random mutation combined with combinatorial mutation was used to improve the resistance of AtATA in organic solvents. Enzyme surface areas are structural elements that undergo reversible conformational transitions, thus affecting the stability of the enzyme in organic solvents. Herein, three surface areas containing three loops were selected as potential mutation regions. And the "best" mutant T23I/T200K/P260S (M3) was acquired. In different concentrations of dimethyl sulfoxide (DMSO), the catalytic efficiency (kcat /Km ) toward 1-acetylnaphthalene and the stability (half-life t1/2 ) were higher than the wild-type (WT) of AtATA. The results of decreased Root Mean Square Fluctuation (RMSF) values via 20-ns molecular dynamics (MD) simulations under 15%, 25%, 35%, and 45% DMSO revealed that mutant M3 had lower flexibility, acquiring a more stable protein structure and contributing to its organic solvents stability than WT. Furthermore, M3 was applied to convert 1-acetylnaphthalene for synthesizing (R)-(+)-1(1-naphthyl)-ethylamine ((R)-NEA), which was an intermediate of Cinacalcet Hydrochloride for the treatment of secondary hyperthyroidism and hypercalcemia. Moreover, in a 20-mL scale-up experiment, 10 mM 1-acetylnaphthalene can be converted to (R)-NEA with 85.2% yield and a strict R-stereoselectivity (enantiomeric excess (e.e.) value >99.5%) within 10 h under 25% DMSO. CONCLUSION The beneficial mutation sites were identified to tailor AtATA's organic solvents stability via regional random mutation. The "best" mutant T23I/T200K/P260S (M3) holds great potential application for the synthesis of (R)-NEA.
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Affiliation(s)
- Chun-Ning Wang
- Key Laboratory of Chemical and Biological Processing Technology for Farm Products of Zhejiang Province, Zhejiang Provincial Collaborative Innovation Center of Agricultural Biological Resources Biochemical Manufacturing, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou, China
| | - Shuai Qiu
- Key Laboratory of Chemical and Biological Processing Technology for Farm Products of Zhejiang Province, Zhejiang Provincial Collaborative Innovation Center of Agricultural Biological Resources Biochemical Manufacturing, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou, China
| | - Fang-Fang Fan
- Key Laboratory of Chemical and Biological Processing Technology for Farm Products of Zhejiang Province, Zhejiang Provincial Collaborative Innovation Center of Agricultural Biological Resources Biochemical Manufacturing, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou, China
| | - Chang-Jiang Lyu
- Key Laboratory of Chemical and Biological Processing Technology for Farm Products of Zhejiang Province, Zhejiang Provincial Collaborative Innovation Center of Agricultural Biological Resources Biochemical Manufacturing, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou, China
| | - Sheng Hu
- School of Biological and Chemical Engineering, Ningbo Tech University, Ningbo, China
| | - Wei-Rui Zhao
- School of Biological and Chemical Engineering, Ningbo Tech University, Ningbo, China
| | - Jia-Qi Mei
- Hangzhou Huadong Medicine Group Co. Ltd, Hangzhou, China
| | - Le-He Mei
- School of Biological and Chemical Engineering, Ningbo Tech University, Ningbo, China
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China
- Jinhua Advanced Research Institute, Jinhua, China
| | - Jun Huang
- Key Laboratory of Chemical and Biological Processing Technology for Farm Products of Zhejiang Province, Zhejiang Provincial Collaborative Innovation Center of Agricultural Biological Resources Biochemical Manufacturing, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou, China
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3
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Hegazy R, Cordara G, Wierenga RK, Richard JP. The Role of Asn11 in Catalysis by Triosephosphate Isomerase. Biochemistry 2023; 62:1794-1806. [PMID: 37162263 PMCID: PMC10249627 DOI: 10.1021/acs.biochem.3c00133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/14/2023] [Indexed: 05/11/2023]
Abstract
Four catalytic amino acids at triosephosphate isomerase (TIM) are highly conserved: N11, K13, H95, and E167. Asparagine 11 is the last of these to be characterized in mutagenesis studies. The ND2 side chain atom of N11 is hydrogen bonded to the O-1 hydroxyl of enzyme-bound dihydroxyacetone phosphate (DHAP), and it sits in an extended chain of hydrogen-bonded side chains that includes T75' from the second subunit. The N11A variants of wild-type TIM from Trypanosoma brucei brucei (TbbTIM) and Leishmania mexicana (LmTIM) undergo dissociation from the dimer to monomer under our assay conditions. Values of Kas = 8 × 103 and 1 × 106 M-1, respectively, were determined for the conversion of monomeric N11A TbbTIM and LmTIM into their homodimers. The N11A substitution at the variant of LmTIM previously stabilized by the E65Q substitution gives the N11A/E65Q variant that is stable to dissociation under our assay conditions. The X-ray crystal structure of N11A/E65Q LmTIM shows an active site that is essentially superimposable on that for wild-type TbbTIM, which also has a glutamine at position 65. A comparison of the kinetic parameters for E65Q LmTIM and N11A/E65Q LmTIM-catalyzed reactions of (R)-glyceraldehyde 3-phosphate (GAP) and (DHAP) shows that the N11A substitution results in a (13-14)-fold decrease in kcat/Km for substrate isomerization and a similar decrease in kcat for DHAP but only a 2-fold decrease in kcat for GAP.
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Affiliation(s)
- Rania Hegazy
- Department
of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United
States
| | - Gabriele Cordara
- Biocenter
Oulu, University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland
| | - Rik K. Wierenga
- Faculty of
Biochemistry and Molecular Medicine, University
of Oulu, P.O. Box 5400, FIN-90014 Oulu, Finland
| | - John P. Richard
- Department
of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United
States
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4
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Cristobal JR, Richard JP. Kinetics and mechanism for enzyme-catalyzed reactions of substrate pieces. Methods Enzymol 2023; 685:95-126. [PMID: 37245916 PMCID: PMC10251411 DOI: 10.1016/bs.mie.2023.03.002] [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] [Indexed: 05/30/2023]
Abstract
The most important difference between enzyme and small molecule catalysts is that only enzymes utilize the large intrinsic binding energies of nonreacting portions of the substrate in stabilization of the transition state for the catalyzed reaction. A general protocol is described to determine the intrinsic phosphodianion binding energy for enzymatic catalysis of reactions of phosphate monoester substrates, and the intrinsic phosphite dianion binding energy in activation of enzymes for catalysis of phosphodianion truncated substrates, from the kinetic parameters for enzyme-catalyzed reactions of whole and truncated substrates. The enzyme-catalyzed reactions so-far documented that utilize dianion binding interactions for enzyme activation; and, their phosphodianion truncated substrates are summarized. A model for the utilization of dianion binding interactions for enzyme activation is described. The methods for the determination of the kinetic parameters for enzyme-catalyzed reactions of whole and truncated substrates, from initial velocity data, are described and illustrated by graphical plots of kinetic data. The results of studies on the effect of site-directed amino acid substitutions at orotidine 5'-monophosphate decarboxylase, triosephosphate isomerase, and glycerol-3-phosphate dehydrogenase provide strong support for the proposal that these enzymes utilize binding interactions with the substrate phosphodianion to hold the protein catalysts in reactive closed conformations.
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Affiliation(s)
- Judith R Cristobal
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY, United States
| | - John P Richard
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY, United States.
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5
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VanDemark AP, Hrizo SL, Eicher SL, Kowalski J, Myers TD, Pfeifer MR, Riley KN, Koeberl DD, Palladino MJ. Itavastatin and resveratrol increase triosephosphate isomerase protein in a newly identified variant of TPI deficiency. Dis Model Mech 2022; 15:274792. [PMID: 35315486 PMCID: PMC9150114 DOI: 10.1242/dmm.049261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 03/14/2022] [Indexed: 11/20/2022] Open
Abstract
Triosephosphate isomerase (TPI) deficiency (TPI Df) is an untreatable glycolytic enzymopathy that results in hemolytic anemia, progressive muscular impairment and irreversible brain damage. Although there is a ‘common’ mutation (TPIE105D), other pathogenic mutations have been described. We identified patients who were compound heterozygous for a newly described mutation, TPIQ181P, and the common TPIE105D mutation. Intriguingly, these patients lacked neuropathy or cognitive impairment. We then initiated biochemical and structural studies of TPIQ181P. Surprisingly, we found that purified TPIQ181P protein had markedly impaired catalytic properties whereas crystallographic studies demonstrated that the TPIQ181P mutation resulted in a highly disordered catalytic lid. We propose that genetic complementation occurs between the two alleles, one with little activity (TPIQ181P) and one with low stability (TPIE105D). Consistent with this, TPIQ181P/E105D fibroblasts exhibit a significant reduction in the TPI protein. These data suggest that impaired stability, and not catalytic activity, is a better predictor of TPI Df severity. Lastly, we tested two recently discovered chemical modulators of mutant TPI stability, itavastatin and resveratrol, and observed a significant increase in TPI in TPIQ181P/E105D patient cells. Summary: A newly identified triosephosphate isomerase (TPI) variant (TPIQ181P) confers TPI deficiency, suggests a molecular and genetic model for its pathogenesis, and the potential for therapeutic intervention.
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Affiliation(s)
- Andrew P VanDemark
- Biological Sciences and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Stacy L Hrizo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.,Department of Biology, Slippery Rock University of Pennsylvania, Slippery Rock, PA 16057, USA
| | - Samantha L Eicher
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Jules Kowalski
- Biological Sciences and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Tracey D Myers
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Megan R Pfeifer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Kacie N Riley
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC 27710, USA
| | - Dwight D Koeberl
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael J Palladino
- Biological Sciences and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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6
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Furey IM, Mehta SC, Sankaran B, Hu L, Prasad BVV, Palzkill T. Local interactions with the Glu166 base and the conformation of an active site loop play key roles in carbapenem hydrolysis by the KPC-2 β-lactamase. J Biol Chem 2021; 296:100799. [PMID: 34022225 PMCID: PMC8189571 DOI: 10.1016/j.jbc.2021.100799] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/06/2021] [Accepted: 05/17/2021] [Indexed: 01/05/2023] Open
Abstract
The Klebsiella pneumoniae carbapenemase-2 (KPC-2) is a common source of antibiotic resistance in Gram-negative bacterial infections. KPC-2 is a class A β-lactamase that exhibits a broad substrate profile and hydrolyzes most β-lactam antibiotics including carbapenems owing to rapid deacylation of the covalent acyl-enzyme intermediate. However, the features that allow KPC-2 to deacylate substrates more rapidly than non-carbapenemase enzymes are not clear. The active-site residues in KPC-2 are largely conserved in sequence and structure compared with non-carbapenemases, suggesting that subtle alterations may collectively facilitate hydrolysis of carbapenems. We utilized a nonbiased genetic approach to identify mutants deficient in carbapenem hydrolysis but competent for ampicillin hydrolysis. Subsequent pre–steady-state enzyme kinetics analyses showed that the substitutions slow the rate of deacylation of carbapenems. Structure determination via X-ray diffraction indicated that a F72Y mutant forms a hydrogen bond between the tyrosine hydroxyl group and Glu166, which may lower basicity and impair the activation of the catalytic water for deacylation, whereas several mutants impact the structure of the Q214-R220 active site loop. A T215P substitution lowers the deacylation rate and drastically alters the conformation of the loop, thereby disrupting interactions between the enzyme and the carbapenem acyl-enzyme intermediate. Thus, the environment of the Glu166 general base and the precise placement and conformational stability of the Q214-R220 loop are critical for efficient deacylation of carbapenems by the KPC-2 enzyme. Therefore, the design of carbapenem antibiotics that interact with Glu166 or alter the Q214-R220 loop conformation may disrupt enzyme function and overcome resistance.
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Affiliation(s)
- Ian M Furey
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Shrenik C Mehta
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Banumathi Sankaran
- Department of Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Liya Hu
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston Texas, USA
| | - B V Venkataram Prasad
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston Texas, USA
| | - Timothy Palzkill
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston Texas, USA.
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7
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The role of ligand-gated conformational changes in enzyme catalysis. Biochem Soc Trans 2020; 47:1449-1460. [PMID: 31657438 PMCID: PMC6824834 DOI: 10.1042/bst20190298] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/03/2019] [Accepted: 10/07/2019] [Indexed: 11/17/2022]
Abstract
Structural and biochemical studies on diverse enzymes have highlighted the importance of ligand-gated conformational changes in enzyme catalysis, where the intrinsic binding energy of the common phosphoryl group of their substrates is used to drive energetically unfavorable conformational changes in catalytic loops, from inactive open to catalytically competent closed conformations. However, computational studies have historically been unable to capture the activating role of these conformational changes. Here, we discuss recent experimental and computational studies, which can remarkably pinpoint the role of ligand-gated conformational changes in enzyme catalysis, even when not modeling the loop dynamics explicitly. Finally, through our joint analyses of these data, we demonstrate how the synergy between theory and experiment is crucial for furthering our understanding of enzyme catalysis.
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8
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Kulkarni YS, Amyes TL, Richard JP, Kamerlin SCL. Uncovering the Role of Key Active-Site Side Chains in Catalysis: An Extended Brønsted Relationship for Substrate Deprotonation Catalyzed by Wild-Type and Variants of Triosephosphate Isomerase. J Am Chem Soc 2019; 141:16139-16150. [PMID: 31508957 PMCID: PMC7032883 DOI: 10.1021/jacs.9b08713] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We report results of detailed empirical valence bond simulations that model the effect of several amino acid substitutions on the thermodynamic (ΔG°) and kinetic activation (ΔG⧧) barriers to deprotonation of dihydroxyacetone phosphate (DHAP) and d-glyceraldehyde 3-phosphate (GAP) bound to wild-type triosephosphate isomerase (TIM), as well as to the K12G, E97A, E97D, E97Q, K12G/E97A, I170A, L230A, I170A/L230A, and P166A variants of this enzyme. The EVB simulations model the observed effect of the P166A mutation on protein structure. The E97A, E97Q, and E97D mutations of the conserved E97 side chain result in ≤1.0 kcal mol-1 decreases in the activation barrier for substrate deprotonation. The agreement between experimental and computed activation barriers is within ±1 kcal mol-1, with a strong linear correlation between ΔG⧧ and ΔG° for all 11 variants, with slopes β = 0.73 (R2 = 0.994) and β = 0.74 (R2 = 0.995) for the deprotonation of DHAP and GAP, respectively. These Brønsted-type correlations show that the amino acid side chains examined in this study function to reduce the standard-state Gibbs free energy of reaction for deprotonation of the weak α-carbonyl carbon acid substrate to form the enediolate phosphate reaction intermediate. TIM utilizes the cationic side chain of K12 to provide direct electrostatic stabilization of the enolate oxyanion, and the nonpolar side chains of P166, I170, and L230 are utilized for the construction of an active-site cavity that provides optimal stabilization of the enediolate phosphate intermediate relative to the carbon acid substrate.
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Affiliation(s)
- Yashraj S Kulkarni
- Science for Life Laboratory, Department of Chemistry - BMC , Uppsala University, BMC , Box 576, S-751 23 Uppsala , Sweden
| | - 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
| | - Shina C L Kamerlin
- Science for Life Laboratory, Department of Chemistry - BMC , Uppsala University, BMC , Box 576, S-751 23 Uppsala , Sweden
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9
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Abstract
![]()
The enormous rate accelerations observed
for many enzyme catalysts
are due to strong stabilizing interactions between the protein and
reaction transition state. The defining property of these catalysts
is their specificity for binding the transition state with a much
higher affinity than substrate. Experimental results are presented
which show that the phosphodianion-binding energy of phosphate monoester
substrates is used to drive conversion of their protein catalysts
from flexible and entropically rich ground states to stiff and catalytically
active Michaelis complexes. These results are generalized to other
enzyme-catalyzed reactions. The existence of many enzymes in flexible,
entropically rich, and inactive ground states provides a mechanism
for utilization of ligand-binding energy to mold these catalysts into
stiff and active forms. This reduces the substrate-binding energy
expressed at the Michaelis complex, while enabling the full and specific
expression of large transition-state binding energies. Evidence is
presented that the complexity of enzyme conformational changes increases
with increases in the enzymatic rate acceleration. The requirement
that a large fraction of the total substrate-binding energy be utilized
to drive conformational changes of floppy enzymes is proposed to favor
the selection and evolution of protein folds with multiple flexible
unstructured loops, such as the TIM-barrel fold. The effect of protein
motions on the kinetic parameters for enzymes that undergo ligand-driven
conformational changes is considered. The results of computational
studies to model the complex ligand-driven conformational change in
catalysis by triosephosphate isomerase are presented.
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Affiliation(s)
- John P Richard
- Department of Chemistry , SUNY, University at Buffalo , Buffalo , New York 14260-3000 , United States
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10
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Reyes AC, Plache DC, Koudelka AP, Amyes TL, Gerlt JA, Richard JP. Enzyme Architecture: Breaking Down the Catalytic Cage that Activates Orotidine 5'-Monophosphate Decarboxylase for Catalysis. J Am Chem Soc 2018; 140:17580-17590. [PMID: 30475611 PMCID: PMC6317530 DOI: 10.1021/jacs.8b09609] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the results of a study of the catalytic role of a network of four interacting amino acid side chains at yeast orotidine 5'-monophosphate decarboxylase ( ScOMPDC), by the stepwise replacement of all four side chains. The H-bond, which links the -CH2OH side chain of S154 from the pyrimidine umbrella loop of ScOMPDC to the amide side chain of Q215 in the phosphodianion gripper loop, creates a protein cage for the substrate OMP. The role of this interaction in optimizing transition state stabilization from the dianion gripper side chains Q215, Y217, and R235 was probed by determining the kinetic parameter kcat/ Km for 16 enzyme variants, which include all combinations of single, double, triple, and quadruple S154A, Q215A, Y217F, and R235A mutations. The effects of consecutive Q215A, Y217F, and R235A mutations on Δ G⧧ for wild-type enzyme-catalyzed decarboxylation sum to 11.6 kcal/mol, but to only 7.6 kcal/mol when starting from S154A mutant. This shows that the S154A mutation results in a (11.6-7.6) = 4.0 kcal/mol decrease in transition state stabilization from interactions with Q215, Y217, and R235. Mutant cycles show that ca. 2 kcal/mol of this 4 kcal/mol effect is from the direct interaction between the S154 and Q215 side chains and that ca. 2 kcal/mol is from a tightening in the stabilizing interactions of the Y217 and R235 side chains. The sum of the effects of individual A154S, A215Q, F217Y and A235R substitutions at the quadruple mutant of ScOMPDC to give the corresponding triple mutants, 5.6 kcal/mol, is much smaller than 16.0 kcal/mol, the sum of the effects of the related four substitutions in wild-type ScOMPDC to give the respective single mutants. The small effect of substitutions at the quadruple mutant is consistent with a large entropic cost to holding the flexible loops of ScOMPDC in the active closed conformation.
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Affiliation(s)
- Archie C Reyes
- Department of Chemistry , University at Buffalo, SUNY , Buffalo , New York 14260-3000 , United States
| | - David C Plache
- 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 A Gerlt
- Department of Chemistry and Biochemistry , University of Illinois , Urbana , Illinois 61801 , United States
| | - John P Richard
- Department of Chemistry , University at Buffalo, SUNY , Buffalo , New York 14260-3000 , United States
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11
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Liao Q, Kulkarni Y, Sengupta U, Petrović D, Mulholland AJ, van der Kamp MW, Strodel B, Kamerlin SCL. Loop Motion in Triosephosphate Isomerase Is Not a Simple Open and Shut Case. J Am Chem Soc 2018; 140:15889-15903. [PMID: 30362343 DOI: 10.1021/jacs.8b09378] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Conformational changes are crucial for the catalytic action of many enzymes. A prototypical and well-studied example is loop opening and closure in triosephosphate isomerase (TIM), which is thought to determine the rate of catalytic turnover in many circumstances. Specifically, TIM loop 6 "grips" the phosphodianion of the substrate and, together with a change in loop 7, sets up the TIM active site for efficient catalysis. Crystal structures of TIM typically show an open or a closed conformation of loop 6, with the tip of the loop moving ∼7 Å between conformations. Many studies have interpreted this motion as a two-state, rigid-body transition. Here, we use extensive molecular dynamics simulations, with both conventional and enhanced sampling techniques, to analyze loop motion in apo and substrate-bound TIM in detail, using five crystal structures of the dimeric TIM from Saccharomyces cerevisiae. We find that loop 6 is highly flexible and samples multiple conformational states. Empirical valence bond simulations of the first reaction step show that slight displacements away from the fully closed-loop conformation can be sufficient to abolish most of the catalytic activity; full closure is required for efficient reaction. The conformational change of the loops in TIM is thus not a simple "open and shut" case and is crucial for its catalytic action. Our detailed analysis of loop motion in a highly efficient enzyme highlights the complexity of loop conformational changes and their role in biological catalysis.
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Affiliation(s)
- Qinghua Liao
- Department of Chemistry - BMC , Uppsala University , BMC Box 576, 751 23 Uppsala , Sweden
| | - Yashraj Kulkarni
- Department of Chemistry - BMC , Uppsala University , BMC Box 576, 751 23 Uppsala , Sweden
| | - Ushnish Sengupta
- Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich , 52425 Jülich , Germany.,German Research School for Simulation Sciences , RWTH Aachen University , 52062 Aachen , Germany
| | - Dušan Petrović
- Department of Chemistry - BMC , Uppsala University , BMC Box 576, 751 23 Uppsala , Sweden.,Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich , 52425 Jülich , Germany
| | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Cantock's Close , BS8 1TS Bristol , United Kingdom
| | - Marc W van der Kamp
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Cantock's Close , BS8 1TS Bristol , United Kingdom.,School of Biochemistry , University of Bristol , University Walk , BS8 1TD Bristol , United Kingdom
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich , 52425 Jülich , Germany.,Institute of Theoretical and Computational Chemistry , Heinrich Heine University Düsseldorf , 40225 Düsseldorf , Germany
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12
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Evaluating the catalytic importance of a conserved Glu97 residue in triosephosphate isomerase. Biochem Biophys Res Commun 2018; 505:492-497. [PMID: 30268499 DOI: 10.1016/j.bbrc.2018.09.076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 09/12/2018] [Indexed: 11/20/2022]
Abstract
Investigating enzyme activity is central to our understanding of biological function, and the design of biocatalysts continues to find applications in synthesis. While a role for active site residues can be proposed based on structure and mechanism, our understanding of the catalytic importance for residues surrounding the active site is less well understood. In triosephosphate isomerase (TIM), Glu97 is situated adjacent to the active site and is found in essentially all sequences. Prior studies reported mutation of Glu97 to Asp and Gln in TIM from Plasmodium falciparum (PfTIM) led to a 100- and 4000-fold decrease in activity, respectively, while the E97D mutation in TIM from Gallus gallus (cTIM) had no effect on activity. To investigate further the question of how mutations in essentially superimposable structures give different effects, we mutated E97 in TIM from Trypanosoma brucei brucei (TbbTIM), Saccharomyces cerevisiae (yTIM), and human (hTIM). The E97D, E97A, and E97Q mutations led to a ∼three-tenfold decrease in activity, a modest effect compared to the 102-103-fold effect in PfTIM. CD and fluorescence studies showed the overall structures for the mutants were essentially unchanged. Structural analysis shows that several residues surrounding E97 differ between PfTIM and TIM from the other organisms, and rearrangements or mispositioning of residues in PfTIM may lead to the different rate effects. The results illustrate the interplay of active site and surrounding residues in affecting catalysis and highlight that understanding of the role of residues surrounding the active site may aid in the incorporation of favorable or avoidance of unfavorable interactions when designing enzymes.
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13
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Zhai X, Reinhardt CJ, Malabanan MM, Amyes TL, Richard JP. Enzyme Architecture: Amino Acid Side-Chains That Function To Optimize the Basicity of the Active Site Glutamate of Triosephosphate Isomerase. J Am Chem Soc 2018; 140:8277-8286. [PMID: 29862813 PMCID: PMC6037162 DOI: 10.1021/jacs.8b04367] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
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We report pH rate profiles for kcat and Km for the
isomerization reaction
of glyceraldehyde 3-phosphate catalyzed by wildtype triosephosphate
isomerase (TIM) from three organisms and by ten mutants of TIM; and,
for Ki for inhibition of this reaction
by phosphoglycolate trianion (I3–). The pH profiles for Ki show
that the binding of I3– to TIM (E) to form EH·I3– is accompanied by
uptake of a proton by the carboxylate side-chain of E165, whose function
is to abstract a proton from substrate. The complexes for several
mutants exist mainly as E–·I3– at high pH, in which cases the pH profiles define the pKa for deprotonation of EH·I3–. The linear
free energy correlation, with slope of 0.73 (r2 = 0.96), between kcat/Km for TIM-catalyzed isomerization and the disassociation
constant of PGA trianion for TIM shows that EH·I3– and the
transition state are stabilized by similar interactions with the protein
catalyst. Values of pKa = 10–10.5
were estimated for deprotonation of EH·I3– for wildtype TIM.
This pKa decreases to as low as 6.3 for
the severely crippled Y208F mutant. There is a correlation between
the effect of several mutations on kcat/Km and on pKa for EH·I3–. The results support a model where the strong basicity of
E165 at the complex to the enediolate reaction intermediate is promoted
by side-chains from Y208 and S211, which serve to clamp loop 6 over
the substrate; I170, which assists in the creation of a hydrophobic
environment for E165; and P166, which functions in driving the carboxylate
side-chain of E165 toward enzyme-bound substrate.
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Affiliation(s)
- Xiang Zhai
- Department of Chemistry , University at Buffalo, SUNY , Buffalo , New York 14260-3000 United States
| | - Christopher J Reinhardt
- Department of Chemistry , University of Illinois at Urbana-Champaign , 600 S Mathews Avenue , Urbana , Illinois 61801 , United States
| | - M Merced Malabanan
- Department of Biochemistry , Vanderbilt University , 842 Robinson Research Building , Nashville , Tennessee 37205 , 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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14
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Reyes AC, Amyes TL, Richard JP. A reevaluation of the origin of the rate acceleration for enzyme-catalyzed hydride transfer. Org Biomol Chem 2018; 15:8856-8866. [PMID: 28956050 DOI: 10.1039/c7ob01652b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
There is no consensus of opinion on the origin of the large rate accelerations observed for enzyme-catalyzed hydride transfer. The interpretation of recent results from studies on hydride transfer reactions catalyzed by alcohol dehydrogenase (ADH) focus on the proposal that the effective barrier height is reduced by quantum-mechanical tunneling through the energy barrier. This interpretation contrasts sharply with the notion that enzymatic rate accelerations are obtained through direct stabilization of the transition state for the nonenzymatic reaction in water. The binding energy of the dianion of substrate DHAP provides 11 kcal mol-1 stabilization of the transition state for the hydride transfer reaction catalyzed by glycerol-3-phosphate dehydrogenase (GPDH). We summarize evidence that the binding interactions between (GPDH) and dianion activators are utilized directly for stabilization of the transition state for enzyme-catalyzed hydride transfer. The possibility is considered, and then discounted, that these dianion binding interactions are utilized for the stabilization of a tunnel ready state (TRS) that enables efficient tunneling of the transferred hydride through the energy barrier, and underneath the energy maximum for the transition state. It is noted that the evidence to support the existence of a tunnel-ready state for the hydride transfer reactions catalyzed by ADH is ambiguous. We propose that the rate acceleration for ADH is due to the utilization of the binding energy of the cofactor NAD+/NADH in the stabilization of the transition state for enzyme-catalyzed hydride transfer.
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Affiliation(s)
- Archie C Reyes
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, USA.
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15
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Kulkarni Y, Liao Q, Petrović D, Krüger DM, Strodel B, Amyes TL, Richard JP, Kamerlin SCL. Enzyme Architecture: Modeling the Operation of a Hydrophobic Clamp in Catalysis by Triosephosphate Isomerase. J Am Chem Soc 2017; 139:10514-10525. [PMID: 28683550 PMCID: PMC5543394 DOI: 10.1021/jacs.7b05576] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Indexed: 12/22/2022]
Abstract
Triosephosphate isomerase (TIM) is a proficient catalyst of the reversible isomerization of dihydroxyacetone phosphate (DHAP) to d-glyceraldehyde phosphate (GAP), via general base catalysis by E165. Historically, this enzyme has been an extremely important model system for understanding the fundamentals of biological catalysis. TIM is activated through an energetically demanding conformational change, which helps position the side chains of two key hydrophobic residues (I170 and L230), over the carboxylate side chain of E165. This is critical both for creating a hydrophobic pocket for the catalytic base and for maintaining correct active site architecture. Truncation of these residues to alanine causes significant falloffs in TIM's catalytic activity, but experiments have failed to provide a full description of the action of this clamp in promoting substrate deprotonation. We perform here detailed empirical valence bond calculations of the TIM-catalyzed deprotonation of DHAP and GAP by both wild-type TIM and its I170A, L230A, and I170A/L230A mutants, obtaining exceptional quantitative agreement with experiment. Our calculations provide a linear free energy relationship, with slope 0.8, between the activation barriers and Gibbs free energies for these TIM-catalyzed reactions. We conclude that these clamping side chains minimize the Gibbs free energy for substrate deprotonation, and that the effects on reaction driving force are largely expressed at the transition state for proton transfer. Our combined analysis of previous experimental and current computational results allows us to provide an overview of the breakdown of ground-state and transition state effects in enzyme catalysis in unprecedented detail, providing a molecular description of the operation of a hydrophobic clamp in triosephosphate isomerase.
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Affiliation(s)
- Yashraj
S. Kulkarni
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, Uppsala S-751 24, Sweden
| | - Qinghua Liao
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, Uppsala S-751 24, Sweden
| | - Dušan Petrović
- Institute
of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Dennis M. Krüger
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, Uppsala S-751 24, Sweden
| | - Birgit Strodel
- Institute
of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, Jülich 52425, Germany
- Institute
of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, Düsseldorf 40225, Germany
| | - 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
| | - Shina C. L. Kamerlin
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, Uppsala S-751 24, Sweden
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16
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Amyes TL, Malabanan MM, Zhai X, Reyes AC, Richard JP. Enzyme activation through the utilization of intrinsic dianion binding energy. Protein Eng Des Sel 2017; 30:157-165. [PMID: 27903763 DOI: 10.1093/protein/gzw064] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/14/2016] [Indexed: 11/12/2022] Open
Abstract
43 We consider 'the proposition that the intrinsic binding energy that results from the noncovalent interaction of a specific substrate with the active site of the enzyme is considerably larger than is generally believed. An important part of this binding energy may be utilized to provide the driving force for catalysis, so that the observed binding energy represents only what is left over after this utilization' [Jencks,W.P. (1975) Adv. Enzymol. Relat. Areas. Mol. Biol. , , 219-410]. The large ~12 kcal/mol intrinsic substrate phosphodianion binding energy for reactions catalyzed by triosephosphate isomerase (TIM), orotidine 5'-monophosphate decarboxylase and glycerol-3-phosphate dehydrogenase is divided into 4-6 kcal/mol binding energy that is expressed on the formation of the Michaelis complex in anchoring substrates to the respective enzyme, and 6-8 kcal/mol binding energy that is specifically expressed at the transition state in activating the respective enzymes for catalysis. A structure-based mechanism is described where the dianion binding energy drives a conformational change that activates these enzymes for catalysis. Phosphite dianion plays the active role of holding TIM in a high-energy closed active form, but acts as passive spectator in showing no effect on transition-state structure. The result of studies on mutant enzymes is presented, which support the proposal that the dianion-driven enzyme conformational change plays a role in enhancing the basicity of side chain of E167, the catalytic base, by clamping the base between a pair of hydrophobic side chains. The insight these results provide into the architecture of enzyme active sites and the development of strategies for the de novo design of protein catalysts is discussed.
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Affiliation(s)
- T L Amyes
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY 14260-3000, USA
| | - M M Malabanan
- Department of Biochemistry, Vanderbilt University, Nashville, TN37205-0146, USA
| | - X Zhai
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX77843-2128, USA
| | - A C Reyes
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY 14260-3000, USA
| | - J P Richard
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, NY 14260-3000, USA
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17
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Olivares-Illana V, Riveros-Rosas H, Cabrera N, Tuena de Gómez-Puyou M, Pérez-Montfort R, Costas M, Gómez-Puyou A. A guide to the effects of a large portion of the residues of triosephosphate isomerase on catalysis, stability, druggability, and human disease. Proteins 2017; 85:1190-1211. [PMID: 28378917 DOI: 10.1002/prot.25299] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/14/2017] [Accepted: 03/27/2017] [Indexed: 12/11/2022]
Abstract
Triosephosphate isomerase (TIM) is a ubiquitous enzyme, which appeared early in evolution. TIM is responsible for obtaining net ATP from glycolysis and producing an extra pyruvate molecule for each glucose molecule, under aerobic and anaerobic conditions. It is placed in a metabolic crossroad that allows a quick balance of the triose phosphate aldolase produced by glycolysis, and is also linked to lipid metabolism through the alternation of glycerol-3-phosphate and the pentose cycle. TIM is one of the most studied enzymes with more than 199 structures deposited in the PDB. The interest for this enzyme stems from the fact that it is involved in glycolysis, but also in aging, human diseases and metabolism. TIM has been a target in the search for chemical compounds against infectious diseases and is a model to study catalytic features. Until February 2017, 62% of all residues of the protein have been studied by mutagenesis and/or using other approaches. Here, we present a detailed and comprehensive recompilation of the reported effects on TIM catalysis, stability, druggability and human disease produced by each of the amino acids studied, contributing to a better understanding of the properties of this fundamental protein. The information reviewed here shows that the role of the noncatalytic residues depend on their molecular context, the delicate balance between the short and long-range interactions in concerted action determining the properties of the protein. Each protein should be regarded as a unique entity that has evolved to be functional in the organism to which it belongs. Proteins 2017; 85:1190-1211. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Vanesa Olivares-Illana
- Laboratorio de Interacciones Biomoleculares y Cáncer. Instituto de Física, Universidad Autónoma de San Luis Potosí, SLP, 78290, México
| | - Hector Riveros-Rosas
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Nallely Cabrera
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Marietta Tuena de Gómez-Puyou
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Ruy Pérez-Montfort
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Miguel Costas
- Laboratorio de Biofisicoquímica, Departamento de Fisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Armando Gómez-Puyou
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
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18
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Amrein BA, Steffen-Munsberg F, Szeler I, Purg M, Kulkarni Y, Kamerlin SCL. CADEE: Computer-Aided Directed Evolution of Enzymes. IUCRJ 2017; 4:50-64. [PMID: 28250941 PMCID: PMC5331465 DOI: 10.1107/s2052252516018017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/09/2016] [Indexed: 05/10/2023]
Abstract
The tremendous interest in enzymes as biocatalysts has led to extensive work in enzyme engineering, as well as associated methodology development. Here, a new framework for computer-aided directed evolution of enzymes (CADEE) is presented which allows a drastic reduction in the time necessary to prepare and analyze in silico semi-automated directed evolution of enzymes. A pedagogical example of the application of CADEE to a real biological system is also presented in order to illustrate the CADEE workflow.
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Affiliation(s)
- Beat Anton Amrein
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden
| | - Fabian Steffen-Munsberg
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden
| | - Ireneusz Szeler
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden
| | - Miha Purg
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden
| | - Yashraj Kulkarni
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden
| | - Shina Caroline Lynn Kamerlin
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden
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19
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Controlling Active Site Loop Dynamics in the (β/α)8 Barrel Enzyme Indole-3-Glycerol Phosphate Synthase. Catalysts 2016. [DOI: 10.3390/catal6090129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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