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Evolution of gene knockout strains of E. coli reveal regulatory architectures governed by metabolism. Nat Commun 2018; 9:3796. [PMID: 30228271 PMCID: PMC6143558 DOI: 10.1038/s41467-018-06219-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 07/27/2018] [Indexed: 01/13/2023] Open
Abstract
Biological regulatory network architectures are multi-scale in their function and can adaptively acquire new functions. Gene knockout (KO) experiments provide an established experimental approach not just for studying gene function, but also for unraveling regulatory networks in which a gene and its gene product are involved. Here we study the regulatory architecture of Escherichia coli K-12 MG1655 by applying adaptive laboratory evolution (ALE) to metabolic gene KO strains. Multi-omic analysis reveal a common overall schema describing the process of adaptation whereby perturbations in metabolite concentrations lead regulatory networks to produce suboptimal states, whose function is subsequently altered and re-optimized through acquisition of mutations during ALE. These results indicate that metabolite levels, through metabolite-transcription factor interactions, have a dominant role in determining the function of a multi-scale regulatory architecture that has been molded by evolution. The function of metabolic genes in the context of regulatory networks is not well understood. Here, the authors investigate the adaptive responses of E. coli after knockout of metabolic genes and highlight the influence of metabolite levels in the evolution of regulatory function.
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Dickmanns A, Zschiedrich CP, Arens J, Parfentev I, Gundlach J, Hofele R, Neumann P, Urlaub H, Görke B, Ficner R, Stülke J. Structural basis for the regulatory interaction of the methylglyoxal synthase MgsA with the carbon flux regulator Crh in Bacillus subtilis. J Biol Chem 2018. [PMID: 29514981 DOI: 10.1074/jbc.ra117.001289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Utilization of energy-rich carbon sources such as glucose is fundamental to the evolutionary success of bacteria. Glucose can be catabolized via glycolysis for feeding the intermediary metabolism. The methylglyoxal synthase MgsA produces methylglyoxal from the glycolytic intermediate dihydroxyacetone phosphate. Methylglyoxal is toxic, requiring stringent regulation of MgsA activity. In the Gram-positive bacterium Bacillus subtilis, an interaction with the phosphoprotein Crh controls MgsA activity. In the absence of preferred carbon sources, Crh is present in the nonphosphorylated state and binds to and thereby inhibits MgsA. To better understand the mechanism of regulation of MgsA, here we performed biochemical and structural analyses of B. subtilis MgsA and of its interaction with Crh. Our results indicated that MgsA forms a hexamer (i.e. a trimer of dimers) in the crystal structure, whereas it seems to exist in an equilibrium between a dimer and hexamer in solution. In the hexamer, two alternative dimers could be distinguished, but only one appeared to prevail in solution. Further analysis strongly suggested that the hexamer is the biologically active form. In vitro cross-linking studies revealed that Crh interacts with the N-terminal helices of MgsA and that the Crh-MgsA binding inactivates MgsA by distorting and thereby blocking its active site. In summary, our results indicate that dimeric and hexameric MgsA species exist in an equilibrium in solution, that the hexameric species is the active form, and that binding to Crh deforms and blocks the active site in MgsA.
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Affiliation(s)
| | | | - Johannes Arens
- From the Departments of Molecular Structural Biology and
| | - Iwan Parfentev
- the Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany, and.,the Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Jan Gundlach
- General Microbiology, GZMB, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Romina Hofele
- the Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany, and.,the Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Piotr Neumann
- From the Departments of Molecular Structural Biology and
| | - Henning Urlaub
- the Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany, and.,the Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Boris Görke
- General Microbiology, GZMB, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Ralf Ficner
- From the Departments of Molecular Structural Biology and
| | - Jörg Stülke
- General Microbiology, GZMB, Georg-August-University Göttingen, 37077 Göttingen, Germany,
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Hatti K, Biswas A, Chaudhary S, Dadireddy V, Sekar K, Srinivasan N, Murthy MRN. Structure determination of contaminant proteins using the MarathonMR procedure. J Struct Biol 2017; 197:372-378. [PMID: 28167161 DOI: 10.1016/j.jsb.2017.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 01/21/2017] [Accepted: 01/24/2017] [Indexed: 10/20/2022]
Abstract
In the recent decades, essential steps of protein structure determination such as phasing by multiple isomorphous replacement and multi wave length anomalous dispersion, molecular replacement, refinement of the structure determined and its validation have been fully automated. Several computer program suites that execute all these steps as a pipeline operation have been made available. In spite of these great advances, determination of a protein structure may turn out to be a challenging task for a variety of reasons. It might be difficult to obtain multiple isomorphous replacement or multi wave length anomalous dispersion data or the crystal may have defects such as twinning or pseudo translation. Apart from these usual difficulties, more frequent difficulties have been encountered in recent years because of the large number of projects handled by structural biologists. These new difficulties usually result from contamination of the protein of interest by other proteins or presence of proteins from pathogenic organisms that could withstand the antibiotics used to prevent bacterial contamination. It could also be a result of poor book keeping. Recently, we have developed a procedure called MarathonMR that has the power to resolve some of these problems automatically. In this communication, we describe how the MarathonMR was used to determine four different protein structures that had remained elusive for several years. We describe the plausible reasons for the difficulties encountered in determining these structures and point out that the method presented here could be a validation tool for protein structures deposited in the protein data bank.
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Affiliation(s)
- Kaushik Hatti
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India; Vittal Mallya Scientific Research Foundation, Kanakapura Road, Bengaluru, Karnataka 560062, India
| | - Ansuman Biswas
- Physics Department, Indian Institute of Science, Bengaluru, Karnataka 560062, India
| | - Santosh Chaudhary
- Physics Department, Indian Institute of Science, Bengaluru, Karnataka 560062, India
| | | | - Kanagaraj Sekar
- Department of Computational and Data Sciences, Indian Institute of Science, Bengaluru, Karnataka 560062, India
| | | | - Mathur R N Murthy
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India.
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Wang Y, Jones MK, Xu H, Ray WK, White RH. Mechanism of the Enzymatic Synthesis of 4-(Hydroxymethyl)-2-furancarboxaldehyde-phosphate (4-HFC-P) from Glyceraldehyde-3-phosphate Catalyzed by 4-HFC-P Synthase. Biochemistry 2015; 54:2997-3008. [DOI: 10.1021/acs.biochem.5b00176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yu Wang
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Michael K. Jones
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Huimin Xu
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - W. Keith Ray
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Robert H. White
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
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Miller D, Wang Y, Xu H, Harich K, White RH. Biosynthesis of the 5-(Aminomethyl)-3-furanmethanol moiety of methanofuran. Biochemistry 2014; 53:4635-47. [PMID: 24977328 DOI: 10.1021/bi500615p] [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
We have established the biosynthetic pathway and the associated genes for the biosynthesis of the 5-(aminomethyl)-3-furanmethanol (F1) moiety of methanofuran in the methanogenic archaeon Methanocaldococcus jannaschii. The recombinant enzyme, derived from the MJ1099 gene, was shown to readily condense glyceraldehyde 3-phosphate (Ga-3P) and dihydroxyacetone-P (DHAP) to form 4-(hydroxymethyl)-2-furancarboxaldehyde phosphate (4-HFC-P). The recombinant purified pyridoxal 5'-phosphate-dependent aminotransferase, derived from the MJ0684 gene, was found to be specific for catalyzing the transamination reaction between 4-HFC-P and [(15)N]alanine to produce [(15)N] 5-(aminomethyl)-3-furanmethanol-P (F1-P) and pyruvate. To confirm these results in cell extracts, we developed sensitive analytical methods for the liquid chromatography-ultraviolet-electrospray ionization mass spectrometry analysis of F1 as a 7-nitrobenzofurazan derivative. This method has allowed for the quantitation of trace amounts of F1 and F1-P in cell extracts and the measurement of the incorporation of stable isotopically labeled precursors into F1. After incubation of cell extracts with [1,2,3-(13)C3]pyruvate and DHAP, 4-([(2)H2]hydroxymethyl)-2-furancarboxylic acid phosphate (4-HFCA-P) or 4-([(2)H2]hydroxymethyl)-2-furancarboxaldehyde phosphate (4-HFC-P) was found to be incorporated into F1-P. 4-HFCA-P and 4-HFC-P were confirmed in cell extracts after removal of the phosphate. The low level of incorporation of [1,2,3-(13)C3]pyruvate into F1-P in these experiments is explained by the fact that the labeled pyruvate must first be converted into Ga-3-P through gluconeogenesis before being incorporated into 4-HFC-P. Cell extracts incubated with 4-HFC-P and a mixture of [(15)N]aspartate, [(15)N]glutamate, and [(15)N]alanine produced [(15)N]F1-P. We also demonstrated that aqueous solutions of methylglyoxal or pyruvate heated with dihydroxyacetone led to the formation of 4-HFC and 4-HFCA, suggesting a possible prebiotic route to this moiety of methanofuran.
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Affiliation(s)
- Danielle Miller
- Department of Biochemistry, Virginia Polytechnic Institute and State University , Blacksburg, Virginia 24061, United States
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Falahati H, Pazhang M, Zareian S, Ghaemi N, Rofougaran R, Hofer A, Rezaie AR, Khajeh K. Transmitting the allosteric signal in methylglyoxal synthase. Protein Eng Des Sel 2013; 26:445-52. [DOI: 10.1093/protein/gzt014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Cloning, expression, and characterization of a novel methylglyoxal synthase from Thermus sp. strain GH5. Appl Biochem Biotechnol 2010; 162:1519-28. [PMID: 20419481 DOI: 10.1007/s12010-010-8933-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 02/12/2010] [Indexed: 10/19/2022]
Abstract
A gene encoding methylglyoxal synthase from Thermus sp. GH5 (TMGS) was cloned, sequenced, overexpressed, and purified by Q-Sepharose. The TMGS gene was composed of 399 bp which encoded a polypeptide of 132 amino acids with a molecular mass of 14.3 kDa. The K (m) and k (cat) values of TMGS were 0.56 mM and 325 (s(-1)), respectively. The enzyme exhibited its optimum activity at pH 6 and 75 degrees C. Comparing the amino acid sequences and Hill coefficients of Escherichia coli MGS and TMGS revealed that the loss of Arg 150 in TMGS has caused a decrease in the cooperativity between the enzyme subunits in the presence of phosphate as an allosteric inhibitor. Gel filtration experiments showed that TMGS is a hexameric enzyme, and its quaternary structure did not change in the presence of phosphate.
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Slepokura K, Lis T. Dihydroxyacetone phosphate, DHAP, in the crystalline state: monomeric and dimeric forms. Carbohydr Res 2009; 345:512-29. [PMID: 20092811 DOI: 10.1016/j.carres.2009.12.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 12/07/2009] [Accepted: 12/09/2009] [Indexed: 11/26/2022]
Abstract
It was shown that dihydroxyacetone phosphate may exist in both monomeric DHAP (C(3)H(7)O(6)P) and dimeric DHAP-dimer (C(6)H(14)O(12)P(2)) form. Monomeric DHAP was obtained in the form of four crystalline salts: CaCl(DHAP) x 2.9H(2)O (7a), Ca(2)Cl(3)(DHAP) x 5H(2)O (7b), CaCl(DHAP) x 2H(2)O (7c), and CaBr(DHAP) x 5H(2)O (7d) by crystallization from aqueous solutions containing DHAP acid and CaCl(2) or CaBr(2), or by direct crystallization from a solution containing DHAP precursor and CaCl(2). At least one of the salts is stable and may be stored in the crystalline state at room temperature for several months. The dimeric form was obtained by slow saturation of free DHAP syrup with ammonia at -18 degrees C and isolated in the form of its hydrated diammonium salt (NH(4))(2)(DHAP-dimer) x 4H(2)O (8). The synthesis of the compounds, their crystallization, and crystal structures determined by X-ray crystallography are described. In all 7a-d monomeric DHAP exists in the monoanionic form in an extended (in-plane) cisoid conformation, with both hydroxyl and ester oxygen atoms being synperiplanar to the carbonyl O atom. The crucial structural feature is the coordination manner, in which the terminal phosphate oxygen atoms act as chelating as well as bridging atoms for the calcium cations. Additionally, the DHAP monoanions chelate another Ca(2+) by the alpha-hydroxycarbonyl moiety, in a manner observed previously in dihydroxyacetone (DHA) calcium chloride complexes. In dimeric 8 the anion is a trans isomer with the dioxane ring in a chair conformation with the hydroxyl groups in axial positions and the phosphomethyl group in an equatorial position.
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Kalapos MP. Methylglyoxal and glucose metabolism: a historical perspective and future avenues for research. ACTA ACUST UNITED AC 2008; 23:69-91. [PMID: 18533365 DOI: 10.1515/dmdi.2008.23.1-2.69] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Methylglyoxal, an alpha-oxoaldehyde discovered in the 1880s, has had a hectic scientific career, at times being considered of fundamental importance and at other times viewed as playing a very subordinate role. Much has been learned about methylglyoxal, but the function of its production in the metabolic machinery is still unknown. This paper gives an overview of the changing role of methylglyoxal from a historical aspect and arrives at the conclusion that methylglyoxal is tightly bound to glycolysis from an evolutionary perspective, its production therefore being inevitable. It is not situated in the main stream of the glycolytic sequence, but a role can be assigned to its production in the phosphate supply of operating glycolysis in some prokaryotes and yeast under conditions of phosphate deficiency. This function is presumed to be performed by the enzyme methylglyoxal synthase, which is specialized for the conversion of dihydroxyacetone-phosphate to methylglyoxal. However, it is still unknown whether this enzyme and this kind of regulation also exist in animals.
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König PH, Hoffmann M, Frauenheim T, Cui Q. A critical evaluation of different QM/MM frontier treatments with SCC-DFTB as the QM method. J Phys Chem B 2007; 109:9082-95. [PMID: 16852081 DOI: 10.1021/jp0442347] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The performance of different link atom based frontier treatments in QM/MM simulations was evaluated critically with SCC-DFTB as the QM method. In addition to the analysis of gas-phase molecules as in previous studies, an important element of the present work is that chemical reactions in realistic enzyme systems were also examined. The schemes tested include all options available in the program CHARMM for SCC-DFTB/MM simulation, which treat electrostatic interactions due to the MM atoms close to the QM/MM boundary in different ways. In addition, a new approach, the divided frontier charge (DIV), has been implemented in which the partial charge associated with the frontier MM atom ("link host") is evenly distributed to the other MM atoms in the same group. The performance of these schemes was evaluated based on properties including proton affinities, deprotonation energies, dipole moments, and energetics of proton transfer reactions. Similar to previous work, it was found that calculated proton affinities and deprotonation energies of alcohols, carbonic acids, amino acids, and model DNA bases are very sensitive to the link atom scheme; the commonly used single link atom approach often gives error on the order of 15 to 20 kcal/mol. Other schemes give better and, on average, mutually comparable results. For proton transfer reactions, encouragingly, both activation barriers and reaction energies are fairly insensitive (within a typical range of 2-4 kcal/mol) to the link atom scheme due to error cancellation, and this was observed for both gas-phase and enzyme systems. Therefore, the effect of using different link atom schemes in QM/MM simulations is rather small for chemical reactions that conserve the total charge. Although the current study used an approximate DFT method as the QM level, the observed trends are expected to be applicable to QM/MM methods with use of other QM approaches. This observation does not mean to encourage QM/MM simulations without careful benchmark in the study of specific systems, rather it emphasizes that other technical details, such as the treatment of long-range electrostatics, tend to play a more important role and need to be handled carefully.
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Affiliation(s)
- P H König
- Theoretische Physik, Universität Paderborn, Warburger Strasse 100, 33098 Paderborn, Germany
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11
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Selective prediction of interaction sites in protein structures with THEMATICS. BMC Bioinformatics 2007; 8:119. [PMID: 17419878 PMCID: PMC1877815 DOI: 10.1186/1471-2105-8-119] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 04/09/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Methods are now available for the prediction of interaction sites in protein 3D structures. While many of these methods report high success rates for site prediction, often these predictions are not very selective and have low precision. Precision in site prediction is addressed using Theoretical Microscopic Titration Curves (THEMATICS), a simple computational method for the identification of active sites in enzymes. Recall and precision are measured and compared with other methods for the prediction of catalytic sites. RESULTS Using a test set of 169 enzymes from the original Catalytic Residue Dataset (CatRes) it is shown that THEMATICS can deliver precise, localised site predictions. Furthermore, adjustment of the cut-off criteria can improve the recall rates for catalytic residues with only a small sacrifice in precision. Recall rates for CatRes/CSA annotated catalytic residues are 41.1%, 50.4%, and 54.2% for Z score cut-off values of 1.00, 0.99, and 0.98, respectively. The corresponding precision rates are 19.4%, 17.9%, and 16.4%. The success rate for catalytic sites is higher, with correct or partially correct predictions for 77.5%, 85.8%, and 88.2% of the enzymes in the test set, corresponding to the same respective Z score cut-offs, if only the CatRes annotations are used as the reference set. Incorporation of additional literature annotations into the reference set gives total success rates of 89.9%, 92.9%, and 94.1%, again for corresponding cut-off values of 1.00, 0.99, and 0.98. False positive rates for a 75-protein test set are 1.95%, 2.60%, and 3.12% for Z score cut-offs of 1.00, 0.99, and 0.98, respectively. CONCLUSION With a preferred cut-off value of 0.99, THEMATICS achieves a high success rate of interaction site prediction, about 86% correct or partially correct using CatRes/CSA annotations only and about 93% with an expanded reference set. Success rates for catalytic residue prediction are similar to those of other structure-based methods, but with substantially better precision and lower false positive rates. THEMATICS performs well across the spectrum of E.C. classes. The method requires only the structure of the query protein as input. THEMATICS predictions may be obtained via the web from structures in PDB format at: http://pfweb.chem.neu.edu/thematics/submit.html.
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Standley DM, Toh H, Nakamura H. GASH: an improved algorithm for maximizing the number of equivalent residues between two protein structures. BMC Bioinformatics 2005; 6:221. [PMID: 16146579 PMCID: PMC1239909 DOI: 10.1186/1471-2105-6-221] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Accepted: 09/08/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We introduce GASH, a new, publicly accessible program for structural alignment and superposition. Alignments are scored by the Number of Equivalent Residues (NER), a quantitative measure of structural similarity that can be applied to any structural alignment method. Multiple alignments are optimized by conjugate gradient maximization of the NER score within the genetic algorithm framework. Initial alignments are generated by the program Local ASH, and can be supplemented by alignments from any other program. RESULTS We compare GASH to DaliLite, CE, and to our earlier program Global ASH on a difficult test set consisting of 3,102 structure pairs, as well as a smaller set derived from the Fischer-Eisenberg set. The extent of alignment crossover, as well as the completeness of the initial set of alignments are examined. The quality of the superpositions is evaluated both by NER and by the number of aligned residues under three different RMSD cutoffs (2,4, and 6A). In addition to the numerical assessment, the alignments for several biologically related structural pairs are discussed in detail. CONCLUSION Regardless of which criteria is used to judge the superposition accuracy, GASH achieves the best overall performance, followed by DaliLite, Global ASH, and CE. In terms of CPU usage, DaliLite CE and GASH perform similarly for query proteins under 500 residues, but for larger proteins DaliLite is faster than GASH or CE. Both an http interface and a simple object application protocol (SOAP) interface to the GASH program are available at http://www.pdbj.org/GASH/.
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Affiliation(s)
- Daron M Standley
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
- Japan Science and Technology Agency, Institute for Bioinformatics Research and Development (BIRD), Japan
| | - Hiroyuki Toh
- Division of Bioinformatics, Medical Institute of Bioregulation, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
| | - Haruki Nakamura
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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Jogl G, Rozovsky S, McDermott AE, Tong L. Optimal alignment for enzymatic proton transfer: structure of the Michaelis complex of triosephosphate isomerase at 1.2-A resolution. Proc Natl Acad Sci U S A 2003; 100:50-5. [PMID: 12509510 PMCID: PMC140880 DOI: 10.1073/pnas.0233793100] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In enzyme catalysis, where exquisitely positioned functionality is the sine qua non, atomic coordinates for a Michaelis complex can provide powerful insights into activation of the substrate. We focus here on the initial proton transfer of the isomerization reaction catalyzed by triosephosphate isomerase and present the crystal structure of its Michaelis complex with the substrate dihydroxyacetone phosphate at near-atomic resolution. The active site is highly compact, with unusually short and bifurcated hydrogen bonds for both catalytic Glu-165 and His-95 residues. The carboxylate oxygen of the catalytic base Glu-165 is positioned in an unprecedented close interaction with the ketone and the alpha-hydroxy carbons of the substrate (C em leader O approximately 3.0 A), which is optimal for the proton transfer involving these centers. The electrophile that polarizes the substrate, His-95, has close contacts to the substrate's O1 and O2 (N em leader O < or = 3.0 and 2.6 A, respectively). The substrate is conformationally relaxed in the Michaelis complex: the phosphate group is out of the plane of the ketone group, and the hydroxy and ketone oxygen atoms are not in the cisoid configuration. The epsilon ammonium group of the electrophilic Lys-12 is within hydrogen-bonding distance of the substrate's ketone oxygen, the bridging oxygen, and a terminal phosphate's oxygen, suggesting a role for this residue in both catalysis and in controlling the flexibility of active-site loop.
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Affiliation(s)
- Gerwald Jogl
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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Cui Q, Karplus M. Catalysis and Specificity in Enzymes: A Study of Triosephosphate Isomerase and Comparison with Methyl Glyoxal Synthase. PROTEIN SIMULATIONS 2003; 66:315-72. [PMID: 14631822 DOI: 10.1016/s0065-3233(03)66008-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Qiang Cui
- Department of Chemistry and Theoretical Chemistry Institute University of Wisconsin, Madison, 1101 University Avenue, Madison, WI 53706, USA
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15
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Zhang X, Harrison DHT, Cui Q. Functional specificities of methylglyoxal synthase and triosephosphate isomerase: a combined QM/MM analysis. J Am Chem Soc 2002; 124:14871-8. [PMID: 12475328 DOI: 10.1021/ja027063x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Combined SCC-DFTB/CHARMM calculations were carried out to analyze the origin for the functional specificities of triosephosphate isomerase (TIM) and methylglyoxal synthase (MGS). The two enzymes bind to the same substrate, dihydroxyacetone phosphate (DHAP), and have rather similar active sites. However, they catalyze different reactions; TIM catalyzes the isomerization of DHAP to glyceraldehyde 3-phosphate (GAP), while MGS catalyzes the elimination of phosphate from DHAP. Similar to previous suggestions, the calculations confirmed that GAP formation is prohibited in MGS due primarily to the reduced flexibility of the catalytic base (Asp 71) compared to that in TIM (Glu 165). For the suppression of phosphate elimination in TIM, the calculations show that the widely accepted stereoelectronic argument that invokes the different phosphoryl torsion angles observed in the X-ray structures of inhibitor complexes of the two enzymes is not as important as electrostatic contributions from the protein and water molecules surrounding the phosphoryl.
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Affiliation(s)
- Xiaodong Zhang
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
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16
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Metzler DE, Metzler CM, Sauke DJ. Enzymatic Addition, Elimination, Condensation, and Isomerization. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50016-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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