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Lemay-St-Denis C, Pelletier JN. From a binding module to essential catalytic activity: how nature stumbled on a good thing. Chem Commun (Camb) 2023; 59:12560-12572. [PMID: 37791701 DOI: 10.1039/d3cc04209j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Enzymes are complex macromolecules capable of catalyzing a wide variety of chemical reactions with high efficiency. Nonetheless, biological catalysis can be rudimentary. Here, we describe an enzyme that is built from a simple protein fold. This short protein sequence - almost a peptide - belongs to the ancient SH3 family of binding modules. Surprisingly, this binding module catalyzes the specific reduction of dihydrofolate using NADPH as a reducing cofactor, making this a dihydrofolate reductase. Too small to provide all the required binding and catalytic machinery on its own, it homotetramerizes, thus creating a large, central active site environment. Remarkably, none of the active site residues is essential to the catalytic function. Instead, backbone interactions juxtapose the reducing cofactor proximal to the target imine of the folate substrate, and a specific motion of the substrate promotes formation of the transition state. In this feature article, we describe the features that make this small protein a functional enzyme capable of catalyzing a metabolically essential reaction, highlighting the characteristics that make it a model for the evolution of primitive enzymes from binding modules.
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Affiliation(s)
- Claudèle Lemay-St-Denis
- PROTEO, The Québec Network for Research on Protein, Function, Engineering and Applications, Quebec, QC, Canada
- CGCC, Center in Green Chemistry and Catalysis, Montreal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC, Canada
| | - Joelle N Pelletier
- PROTEO, The Québec Network for Research on Protein, Function, Engineering and Applications, Quebec, QC, Canada
- CGCC, Center in Green Chemistry and Catalysis, Montreal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC, Canada
- Chemistry Department, Université de Montréal, Montreal, QC, Canada.
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2
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Schubert MG, Goodman DB, Wannier TM, Kaur D, Farzadfard F, Lu TK, Shipman SL, Church GM. High-throughput functional variant screens via in vivo production of single-stranded DNA. Proc Natl Acad Sci U S A 2021; 118:e2018181118. [PMID: 33906944 PMCID: PMC8106316 DOI: 10.1073/pnas.2018181118] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Creating and characterizing individual genetic variants remains limited in scale, compared to the tremendous variation both existing in nature and envisioned by genome engineers. Here we introduce retron library recombineering (RLR), a methodology for high-throughput functional screens that surpasses the scale and specificity of CRISPR-Cas methods. We use the targeted reverse-transcription activity of retrons to produce single-stranded DNA (ssDNA) in vivo, incorporating edits at >90% efficiency and enabling multiplexed applications. RLR simultaneously introduces many genomic variants, producing pooled and barcoded variant libraries addressable by targeted deep sequencing. We use RLR for pooled phenotyping of synthesized antibiotic resistance alleles, demonstrating quantitative measurement of relative growth rates. We also perform RLR using the sheared genomic DNA of an evolved bacterium, experimentally querying millions of sequences for causal variants, demonstrating that RLR is uniquely suited to utilize large pools of natural variation. Using ssDNA produced in vivo for pooled experiments presents avenues for exploring variation across the genome.
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Affiliation(s)
- Max G Schubert
- Department of Genetics, Harvard Medical School, Boston, MA 02115;
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
| | - Daniel B Goodman
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143
| | | | - Divjot Kaur
- Department of Zoology, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Fahim Farzadfard
- Research Laboratory of Electronics, Massachussetts Institute of Technology, Cambridge, MA 02139
| | - Timothy K Lu
- Research Laboratory of Electronics, Massachussetts Institute of Technology, Cambridge, MA 02139
| | - Seth L Shipman
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA 94158
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA 02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Research Laboratory of Electronics, Massachussetts Institute of Technology, Cambridge, MA 02139
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3
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Directed evolution of multiple genomic loci allows the prediction of antibiotic resistance. Proc Natl Acad Sci U S A 2018; 115:E5726-E5735. [PMID: 29871954 PMCID: PMC6016788 DOI: 10.1073/pnas.1801646115] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Antibiotic development is frequently plagued by the rapid emergence of drug resistance. However, assessing the risk of resistance development in the preclinical stage is difficult. Standard laboratory evolution approaches explore only a small fraction of the sequence space and fail to identify exceedingly rare resistance mutations and combinations thereof. Therefore, new rapid and exhaustive methods are needed to accurately assess the potential of resistance evolution and uncover the underlying mutational mechanisms. Here, we introduce directed evolution with random genomic mutations (DIvERGE), a method that allows an up to million-fold increase in mutation rate along the full lengths of multiple predefined loci in a range of bacterial species. In a single day, DIvERGE generated specific mutation combinations, yielding clinically significant resistance against trimethoprim and ciprofloxacin. Many of these mutations have remained previously undetected or provide resistance in a species-specific manner. These results indicate pathogen-specific resistance mechanisms and the necessity of future narrow-spectrum antibacterial treatments. In contrast to prior claims, we detected the rapid emergence of resistance against gepotidacin, a novel antibiotic currently in clinical trials. Based on these properties, DIvERGE could be applicable to identify less resistance-prone antibiotics at an early stage of drug development. Finally, we discuss potential future applications of DIvERGE in synthetic and evolutionary biology.
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Sunden F, AlSadhan I, Lyubimov AY, Ressl S, Wiersma-Koch H, Borland J, Brown CL, Johnson TA, Singh Z, Herschlag D. Mechanistic and Evolutionary Insights from Comparative Enzymology of Phosphomonoesterases and Phosphodiesterases across the Alkaline Phosphatase Superfamily. J Am Chem Soc 2016; 138:14273-14287. [PMID: 27670607 PMCID: PMC5096464 DOI: 10.1021/jacs.6b06186] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Naively one might have expected an early division between phosphate monoesterases and diesterases of the alkaline phosphatase (AP) superfamily. On the contrary, prior results and our structural and biochemical analyses of phosphate monoesterase PafA, from Chryseobacterium meningosepticum, indicate similarities to a superfamily phosphate diesterase [Xanthomonas citri nucleotide pyrophosphatase/phosphodiesterase (NPP)] and distinct differences from the three metal ion AP superfamily monoesterase, from Escherichia coli AP (EcAP). We carried out a series of experiments to map out and learn from the differences and similarities between these enzymes. First, we asked why there would be independent instances of monoesterases in the AP superfamily? PafA has a much weaker product inhibition and slightly higher activity relative to EcAP, suggesting that different metabolic evolutionary pressures favored distinct active-site architectures. Next, we addressed the preferential phosphate monoester and diester catalysis of PafA and NPP, respectively. We asked whether the >80% sequence differences throughout these scaffolds provide functional specialization for each enzyme's cognate reaction. In contrast to expectations from this model, PafA and NPP mutants with the common subset of active-site groups embedded in each native scaffold had the same monoesterase:diesterase specificities; thus, the >107-fold difference in native specificities appears to arise from distinct interactions at a single phosphoryl substituent. We also uncovered striking mechanistic similarities between the PafA and EcAP monoesterases, including evidence for ground-state destabilization and functional active-site networks that involve different active-site groups but may play analogous catalytic roles. Discovering common network functions may reveal active-site architectural connections that are critical for function, and identifying regions of functional modularity may facilitate the design of new enzymes from existing promiscuous templates. More generally, comparative enzymology and analysis of catalytic promiscuity can provide mechanistic and evolutionary insights.
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Affiliation(s)
- Fanny Sunden
- Department of Biochemistry, Beckman Center, Stanford University , Stanford, California 94305, United States
| | - Ishraq AlSadhan
- Department of Biochemistry, Beckman Center, Stanford University , Stanford, California 94305, United States
| | - Artem Y Lyubimov
- Departments of Molecular and Cellular Physiology, Neurology and Neurological Science, Structural Biology, and Photon Science, Howard Hughes Medical Institute, Stanford University , Stanford, California 94305, United States
| | - Susanne Ressl
- Molecular and Cellular Biochemistry Department, Indiana University , Bloomington, Indiana 47405, United States
| | - Helen Wiersma-Koch
- Department of Biochemistry, Beckman Center, Stanford University , Stanford, California 94305, United States.,Department of Biology, Indian River State College , Fort Pierce, Florida 34981, United States
| | - Jamar Borland
- Department of Biochemistry, Beckman Center, Stanford University , Stanford, California 94305, United States
| | - Clayton L Brown
- Department of Biochemistry, Beckman Center, Stanford University , Stanford, California 94305, United States
| | - Tory A Johnson
- Department of Biochemistry, Beckman Center, Stanford University , Stanford, California 94305, United States
| | - Zorawar Singh
- Department of Biochemistry, Beckman Center, Stanford University , Stanford, California 94305, United States
| | - Daniel Herschlag
- Department of Biochemistry, Beckman Center, Stanford University , Stanford, California 94305, United States.,Departments of Chemical Engineering and Chemistry, and Stanford ChEM-H (Chemistry, Engineering, and Medicine for Human Health), Stanford University , Stanford, California 94305, United States
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5
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Wong HE, Pack SP, Kwon I. Positional effects of hydrophobic non-natural amino acid mutagenesis into the surface region of murine dihydrofolate reductase on enzyme properties. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2015.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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6
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Sunden F, Peck A, Salzman J, Ressl S, Herschlag D. Extensive site-directed mutagenesis reveals interconnected functional units in the alkaline phosphatase active site. eLife 2015; 4. [PMID: 25902402 PMCID: PMC4438272 DOI: 10.7554/elife.06181] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 04/22/2015] [Indexed: 01/30/2023] Open
Abstract
Enzymes enable life by accelerating reaction rates to biological timescales. Conventional studies have focused on identifying the residues that have a direct involvement in an enzymatic reaction, but these so-called 'catalytic residues' are embedded in extensive interaction networks. Although fundamental to our understanding of enzyme function, evolution, and engineering, the properties of these networks have yet to be quantitatively and systematically explored. We dissected an interaction network of five residues in the active site of Escherichia coli alkaline phosphatase. Analysis of the complex catalytic interdependence of specific residues identified three energetically independent but structurally interconnected functional units with distinct modes of cooperativity. From an evolutionary perspective, this network is orders of magnitude more probable to arise than a fully cooperative network. From a functional perspective, new catalytic insights emerge. Further, such comprehensive energetic characterization will be necessary to benchmark the algorithms required to rationally engineer highly efficient enzymes.
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Affiliation(s)
- Fanny Sunden
- Department of Biochemistry, Beckman Center, Stanford University, Stanford, United States
| | - Ariana Peck
- Department of Biochemistry, Beckman Center, Stanford University, Stanford, United States
| | - Julia Salzman
- Department of Biochemistry, Beckman Center, Stanford University, Stanford, United States
| | - Susanne Ressl
- Molecular and Cellular Biochemistry Department, Indiana University Bloomington, Bloomington, United States
| | - Daniel Herschlag
- Department of Biochemistry, Beckman Center, Stanford University, Stanford, United States
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7
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Bhojane PP, Duff MR, Patel HC, Vogt ME, Howell EE. Investigation of osmolyte effects on FolM: comparison with other dihydrofolate reductases. Biochemistry 2014; 53:1330-41. [PMID: 24517487 DOI: 10.1021/bi4014165] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A weak association between osmolytes and dihydrofolate (DHF) decreases the affinity of the substrate for the Escherichia coli chromosomal and R67 plasmid dihydrofolate reductase (DHFR) enzymes. To test whether the osmolyte-DHF association also interferes with binding of DHF to FolM, an E. coli enzyme that possesses weak DHFR activity, ligand binding was monitored in the presence of osmolytes. The affinity of FolM for DHF, measured by kcat/Km(DHF), was decreased by the addition of an osmolyte. Additionally, binding of the antifolate drug, methotrexate, to FolM was weakened by the addition of an osmolyte. The changes in ligand binding with water activity were unique for each osmolyte, indicating preferential interaction between the osmolyte and folate and its derivatives; however, additional evidence provided support for further interactions between FolM and osmolytes. Binding of the reduced nicotinamide adenine dinucleotide phosphate (NADPH) cofactor to FolM was monitored by isothermal titration calorimetry as a control for protein-osmolyte association. In the presence of betaine (proposed to be the osmolyte most excluded from protein surfaces), the NADPH Kd decreased, consistent with dehydration effects. However, other osmolytes did not tighten binding to the cofactor. Rather, dimethyl sulfoxide (DMSO) had no effect on the NADPH Kd, while ethylene glycol and polyethylene glycol 400 weakened cofactor binding. Differential scanning calorimetry of FolM in the presence of osmolytes showed that both DMSO and ethylene glycol decreased the stability of FolM, while betaine increased the stability of the protein. These results suggest that some osmolytes can destabilize FolM by preferentially interacting with the protein. Further, these weak attractions can impede ligand binding. These various contributions have to be considered when interpreting osmotic pressure results.
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Affiliation(s)
- Purva P Bhojane
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996-0840, United States
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8
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Martucci WE, Rodriguez JM, Vargo MA, Marr M, Hamilton AD, Anderson KS. Exploring novel strategies for AIDS protozoal pathogens: α-helix mimetics targeting a key allosteric protein-protein interaction in C. hominis TS-DHFR. MEDCHEMCOMM 2013; 4. [PMID: 24324854 DOI: 10.1039/c3md00141e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bifunctional enzyme thymidylate synthase-dihydrofolate reductase (TS-DHFR) from the protozoal parasite Cryptosporidium hominis is a potential molecular target for the design of antiparasitic therapies for AIDS-related opportunistic infections. The enzyme exists as a homodimer with each monomer containing a unique swap domain known as a "crossover helix" that binds in a cleft on the adjacent DHFR active site. This crossover helix is absent in species containing monofunctional forms of DHFR such as human. An in-depth understanding of protein-protein interactions between the crossover helix and adjacent DHFR active site that might modulate enzyme integrity or function would allow for insights into rational design of species-specific allosteric inhibitors. Mutational analysis coupled with structural studies and biophysical and kinetic characterization of crossover helix mutants identifies this domain as essential for full enzyme stability and catalytic activity, and pinpoints these effects to distinct faces of the crossover helix important in protein-protein interactions. Moreover, targeting this helical protein interaction with α-helix mimetics of the crossover helix leads to selective inhibition and destabilization of the C. hominis TS-DHFR enzyme, thus validating this region as a new avenue to explore for species-specific inhibitor design.
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Affiliation(s)
- W Edward Martucci
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA ; Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
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9
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Lee J, Goodey NM. Catalytic contributions from remote regions of enzyme structure. Chem Rev 2011; 111:7595-624. [PMID: 21923192 DOI: 10.1021/cr100042n] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Jeeyeon Lee
- Department of Chemistry, 413 Wartik Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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10
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Bennett B, Langan P, Coates L, Mustyakimov M, Schoenborn B, Howell EE, Dealwis C. Neutron diffraction studies of Escherichia coli dihydrofolate reductase complexed with methotrexate. Proc Natl Acad Sci U S A 2006; 103:18493-8. [PMID: 17130456 PMCID: PMC1664550 DOI: 10.1073/pnas.0604977103] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hydrogen atoms play a central role in many biochemical processes yet are difficult to visualize by x-ray crystallography. Spallation neutron sources provide a new arena for protein crystallography with TOF measurements enhancing data collection efficiency and allowing hydrogen atoms to be located in smaller crystals of larger biological macromolecules. Here we report a 2.2-A resolution neutron structure of Escherichia coli dihydrofolate reductase (DHFR) in complex with methotrexate (MTX). Neutron data were collected on a 0.3-mm(3) D(2)O-soaked crystal at the Los Alamos Neutron Scattering Center. This study provides an example of using spallation neutrons to study protein dynamics, to identify protonation states directly from nuclear density maps, and to analyze solvent structure. Our structure reveals that the occluded loop conformation [monomer (mon.) A] of the DHFR.MTX complex undergoes greater H/D exchange compared with the closed-loop conformer (mon. B), partly because the Met-20 and beta(F-G) loops readily exchange in mon. A. The eight-stranded beta sheet of both DHFR molecules resists H/D exchange more than the helices and loops. However, the C-terminal strand, betaH, in mon. A is almost fully exchanged. Several D(2)Os form hydrogen bonds with exchanged amides. At the active site, the N1 atom of MTX is protonated and thus charged when bound to DHFR. Several D(2)Os are observed at hydrophobic surfaces, including two pockets near the MTX-binding site. A previously unidentified D(2)O hydrogen bonds with the catalytic D27 in mon. B, stabilizing its negative charge.
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Affiliation(s)
- Brad Bennett
- *Department of Biochemistry, Cellular and Molecular Biology, M407 Walters Life Sciences, University of Tennessee, Knoxville, TN 37996; and
| | - Paul Langan
- Los Alamos National Laboratory, Biosciences Division, Mail Stop MS M888, Los Alamos, NM 87545
| | - Leighton Coates
- Los Alamos National Laboratory, Biosciences Division, Mail Stop MS M888, Los Alamos, NM 87545
| | - Marat Mustyakimov
- Los Alamos National Laboratory, Biosciences Division, Mail Stop MS M888, Los Alamos, NM 87545
| | - Benno Schoenborn
- Los Alamos National Laboratory, Biosciences Division, Mail Stop MS M888, Los Alamos, NM 87545
| | - Elizabeth E. Howell
- *Department of Biochemistry, Cellular and Molecular Biology, M407 Walters Life Sciences, University of Tennessee, Knoxville, TN 37996; and
| | - Chris Dealwis
- *Department of Biochemistry, Cellular and Molecular Biology, M407 Walters Life Sciences, University of Tennessee, Knoxville, TN 37996; and
- To whom correspondence should be addressed. E-mail:
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11
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Howell EE. Searching sequence space: two different approaches to dihydrofolate reductase catalysis. Chembiochem 2005; 6:590-600. [PMID: 15812782 DOI: 10.1002/cbic.200400237] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
There are numerous examples of proteins that catalyze the same reaction while possessing different structures. This review focuses on two dihydrofolate reductases (DHFRs) that have disparate structures and discusses how the catalytic strategies of these two DHFRs are driven by their respective scaffolds. The two proteins are E. coli chromosomal DHFR (Ec DHFR) and a type II R-plasmid-encoded DHFR, typified by R67 DHFR. The former has been described as a very well evolved enzyme with an efficiency of 0.15, while the latter has been suggested to be a model for a "primitive" enzyme that has not yet been optimized by evolution. This comparison underlines what is important to catalysis in these two enzymes and concurrently highlights fundamental issues in enzyme catalysis.
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Affiliation(s)
- Elizabeth E Howell
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996-0840, USA.
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12
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Sirawaraporn W, Sirawaraporn R, Yongkiettrakul S, Anuwatwora A, Rastelli G, Kamchonwongpaisan S, Yuthavong Y. Mutational analysis of Plasmodium falciparum dihydrofolate reductase: the role of aspartate 54 and phenylalanine 223 on catalytic activity and antifolate binding. Mol Biochem Parasitol 2002; 121:185-93. [PMID: 12034452 DOI: 10.1016/s0166-6851(02)00035-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The catalytic activity and ability to confer resistance to antifolates of Plasmodium falciparum dihydrofolate reductase (pfDHFR) through single and double mutations at Asp-54 and Phe-223 were investigated. A single Asp54Glu (D54E) mutation in the pfDHFR domain greatly decreased the catalytic activity of the enzyme and affected both the K(m) values for the substrate dihydrofolate and the K(i) values for pyrimethamine, cycloguanil and WR99210. The Phe223Ser (F223S) single mutant had unperturbed kinetics but had very poor affinity with the first two antifolates. The ability to confer high resistance to the antifolates of F223S enzyme was, however, abolished in the D54E+F223S double mutant enzyme. When D54E mutation was present together with the A16V+S108T double mutation, the effects on the K(m) values for the substrate dihydrofolate and the binding affinity of antifolates were much more pronounced. The severely impaired kinetics and poor activity observed in A16V+S108T+D54E enzyme could, however, be restored when F223S was introduced, while the binding affinities to the antifolates remained poor. The experimental findings can be explained with a model for substrate and inhibitor binding. Our data not only indicate the importance of Asp-54 of pfDHFR in catalysis and inhibitor binding, but also provide evidence that infer the potentially crucial function of the C-terminal portion of pfDHFR domain.
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Affiliation(s)
- Worachart Sirawaraporn
- Department of Biochemistry, Faculty of Science, Mahidol University, Rama 6 Rd., 10400, Bangkok 10400, Thailand.
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13
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Radkiewicz JL, Brooks CL. Protein Dynamics in Enzymatic Catalysis: Exploration of Dihydrofolate Reductase. J Am Chem Soc 2000. [DOI: 10.1021/ja9913838] [Citation(s) in RCA: 261] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Karginov VA, Mamaev SV, An H, Van Cleve MD, Hecht SM, Komatsoulis GA, Abelson JN. Probing the Role of an Active Site Aspartic Acid in Dihydrofolate Reductase. J Am Chem Soc 1997. [DOI: 10.1021/ja971099l] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vladimir A. Karginov
- Contribution from the Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia, 22901, and Division of Biology, California Institute of Technology, Pasadena, California, 91125
| | - Sergey V. Mamaev
- Contribution from the Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia, 22901, and Division of Biology, California Institute of Technology, Pasadena, California, 91125
| | - Haoyun An
- Contribution from the Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia, 22901, and Division of Biology, California Institute of Technology, Pasadena, California, 91125
| | - Mark D. Van Cleve
- Contribution from the Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia, 22901, and Division of Biology, California Institute of Technology, Pasadena, California, 91125
| | - Sidney M. Hecht
- Contribution from the Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia, 22901, and Division of Biology, California Institute of Technology, Pasadena, California, 91125
| | - George A. Komatsoulis
- Contribution from the Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia, 22901, and Division of Biology, California Institute of Technology, Pasadena, California, 91125
| | - John N. Abelson
- Contribution from the Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia, 22901, and Division of Biology, California Institute of Technology, Pasadena, California, 91125
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