1
|
Yuan J, Liu R, Sheng S, Fu H, Wang X. Untargeted LC-MS/MS-Based Metabolomic Profiling for the Edible and Medicinal Plant Salvia miltiorrhiza Under Different Levels of Cadmium Stress. FRONTIERS IN PLANT SCIENCE 2022; 13:889370. [PMID: 35968141 PMCID: PMC9366474 DOI: 10.3389/fpls.2022.889370] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/23/2022] [Indexed: 06/01/2023]
Abstract
Salvia miltiorrhiza, a medicinal and edible plant, has been extensively applied to treat cardiovascular diseases and chronic hepatitis. Cadmium (Cd) affects the quality of S. miltiorrhiza, posing serious threats to human health. To reveal the metabolic mechanisms of S. miltiorrhiza's resistance to Cd stress, metabolite changes in S. miltiorrhiza roots treated with 0 (CK), 25 (T1), 50 (T2) and 100 (T3) mg kg-1 Cd by liquid chromatography coupled to mass spectrometry (LC-MS/MS) were investigated. A total of 305 metabolites were identified, and most of them were amino acids, organic acids and fatty acids, which contributed to the discrimination of CK from the Cd-treated groups. Among them, S. miltiorrhiza mainly upregulated o-tyrosine, chorismate and eudesmic acid in resistance to 25 mg kg-1 Cd; DL-tryptophan, L-aspartic acid, L-proline and chorismite in resistance to 50 mg kg-1 Cd; and L-proline, L-serine, L-histidine, eudesmic acid, and rosmarinic acid in resistance to 100 mg kg-1 Cd. It mainly downregulated unsaturated fatty acids (e.g., oleic acid, linoleic acid) in resistance to 25, 50, and 100 mg kg-1 Cd and upregulated saturated fatty acids (especially stearic acid) in resistance to 100 mg kg-1 Cd. Biosynthesis of unsaturated fatty acids, isoquinoline alkaloid, betalain, aminoacyl-tRNA, and tyrosine metabolism were the significantly enriched metabolic pathways and the most important pathways involved in the Cd resistance of S. miltiorrhiza. These data elucidated the crucial metabolic mechanisms involved in S. miltiorrhiza Cd resistance and the crucial metabolites that could be used to improve resistance to Cd stress in medicinal plant breeding.
Collapse
Affiliation(s)
- Jun Yuan
- School of Nursing, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Rongpeng Liu
- Research Center for Traditional Chinese Medicine Resources and Ethnic Minority Medicine, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Shasha Sheng
- Research Center for Traditional Chinese Medicine Resources and Ethnic Minority Medicine, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Haihui Fu
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang, China
| | - Xiaoyun Wang
- Research Center for Traditional Chinese Medicine Resources and Ethnic Minority Medicine, Jiangxi University of Chinese Medicine, Nanchang, China
| |
Collapse
|
2
|
Hubrich F, Müller M, Andexer JN. Chorismate- and isochorismate converting enzymes: versatile catalysts acting on an important metabolic node. Chem Commun (Camb) 2021; 57:2441-2463. [PMID: 33605953 DOI: 10.1039/d0cc08078k] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chorismate and isochorismate represent an important branching point connecting primary and secondary metabolism in bacteria, fungi, archaea and plants. Chorismate- and isochorismate-converting enzymes are potential targets for new bioactive compounds, as well as valuable biocatalysts for the in vivo and in vitro synthesis of fine chemicals. The diversity of the products of chorismate- and isochorismate-converting enzymes is reflected in the enzymatic three-dimensional structures and molecular mechanisms. Due to the high reactivity of chorismate and its derivatives, these enzymes have evolved to be accurately tailored to their respective reaction; at the same time, many of them exhibit a fascinating flexibility regarding side reactions and acceptance of alternative substrates. Here, we give an overview of the different (sub)families of chorismate- and isochorismate-converting enzymes, their molecular mechanisms, and three-dimensional structures. In addition, we highlight important results of mutagenetic approaches that generate a broader understanding of the influence of distinct active site residues for product formation and the conversion of one subfamily into another. Based on this, we discuss to what extent the recent advances in the field might influence the general mechanistic understanding of chorismate- and isochorismate-converting enzymes. Recent discoveries of new chorismate-derived products and pathways, as well as biocatalytic conversions of non-physiological substrates, highlight how this vast field is expected to continue developing in the future.
Collapse
Affiliation(s)
- Florian Hubrich
- ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
| | | | | |
Collapse
|
3
|
Mori M, Stelitano G, Gelain A, Pini E, Chiarelli LR, Sammartino JC, Poli G, Tuccinardi T, Beretta G, Porta A, Bellinzoni M, Villa S, Meneghetti F. Shedding X-ray Light on the Role of Magnesium in the Activity of Mycobacterium tuberculosis Salicylate Synthase (MbtI) for Drug Design. J Med Chem 2020; 63:7066-7080. [PMID: 32530281 PMCID: PMC8008425 DOI: 10.1021/acs.jmedchem.0c00373] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
The
Mg2+-dependent Mycobacterium tuberculosis salicylate synthase (MbtI) is a key enzyme involved in the biosynthesis
of siderophores. Because iron is essential for the survival and pathogenicity
of the microorganism, this protein constitutes an attractive target
for antitubercular therapy, also considering the absence of homologous
enzymes in mammals. An extension of the structure–activity
relationships of our furan-based candidates allowed us to disclose
the most potent competitive inhibitor known to date (10, Ki = 4 μM), which also proved
effective on mycobacterial cultures. By structural studies, we characterized
its unexpected Mg2+-independent binding mode. We also investigated
the role of the Mg2+ cofactor in catalysis, analyzing the
first crystal structure of the MbtI–Mg2+–salicylate
ternary complex. Overall, these results pave the way for the development
of novel antituberculars through the rational design of improved MbtI
inhibitors.
Collapse
Affiliation(s)
- Matteo Mori
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano,Italy
| | - Giovanni Stelitano
- Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, via A. Ferrata 9, 27100 Pavia, Italy
| | - Arianna Gelain
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano,Italy
| | - Elena Pini
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano,Italy
| | - Laurent R Chiarelli
- Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, via A. Ferrata 9, 27100 Pavia, Italy
| | - José C Sammartino
- Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", Università degli Studi di Pavia, via A. Ferrata 9, 27100 Pavia, Italy
| | - Giulio Poli
- Dipartimento di Farmacia, Università di Pisa, via Bonanno Pisano 6, 56126 Pisa, Italy
| | - Tiziano Tuccinardi
- Dipartimento di Farmacia, Università di Pisa, via Bonanno Pisano 6, 56126 Pisa, Italy.,Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Giangiacomo Beretta
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, via G. Celoria 2, 20133 Milano, Italy
| | - Alessio Porta
- Dipartimento di Chimica, Università degli Studi di Pavia, via T. Taramelli 12, 27100 Pavia, Italy
| | - Marco Bellinzoni
- Unité de Microbiologie Structurale, Institut Pasteur, CNRS, Université de Paris, F-75015 Paris, France
| | - Stefania Villa
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano,Italy
| | - Fiorella Meneghetti
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, via L. Mangiagalli 25, 20133 Milano,Italy
| |
Collapse
|
4
|
Che Q, Qiao L, Han X, Liu Y, Wang W, Gu Q, Zhu T, Li D. Anthranosides A-C, Anthranilate Derivatives from a Sponge-Derived Streptomyces sp. CMN-62. Org Lett 2018; 20:5466-5469. [PMID: 30106304 DOI: 10.1021/acs.orglett.8b02382] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three new derivatives, anthranosides A-C (1-3), were discovered from a marine sponge-derived actinomycete Streptomyces sp. CMN-62. Their structures including absolute configurations were elucidated using MS and NMR spectroscopic data, X-ray single-crystal diffraction analysis, and chemical synthesis. Compounds 1 and 2 are epimers composed by linking the anthranilate unit to the fructofuranose moiety via a carbon-nitrogen bond, while 3 possessed a unique indole-containing scaffold. All compounds were tested for cytotoxicity, anti-influenza H1N1 virus, and NFκB inhibitory activities, and 3 showed anti-influenza activity. A possible Amadori rearrangement-based biosynthetic pathway was proposed to generate compounds 1-3.
Collapse
Affiliation(s)
- Qian Che
- School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China
| | - Liang Qiao
- School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China
| | - Xiaoning Han
- School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China
| | - Yankai Liu
- School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China
| | - Wei Wang
- School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China
| | - Qianqun Gu
- School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China
| | - Tianjiao Zhu
- School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China
| | - Dehai Li
- School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology , Qingdao 266237 , People's Republic of China
| |
Collapse
|
5
|
Shelton CL, Lamb AL. Unraveling the Structure and Mechanism of the MST(ery) Enzymes. Trends Biochem Sci 2018; 43:342-357. [PMID: 29573882 DOI: 10.1016/j.tibs.2018.02.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 02/23/2018] [Accepted: 02/27/2018] [Indexed: 01/06/2023]
Abstract
The menaquinone, siderophore, and tryptophan (MST) enzymes transform chorismate to generate precursor molecules for the biosynthetic pathways defined in their name. Kinetic data, both steady-state and transient-state, and X-ray crystal structures indicate that these enzymes are highly conserved both in mechanism and in structure. Because these enzymes are found in pathogens but not in humans, there is considerable interest in these enzymes as drug design targets. While great progress has been made in defining enzyme structure and mechanism, inhibitor design has lagged behind. This review provides a detailed description of the evidence that begins to unravel the mystery of how the MST enzymes work, and how that information has been used in inhibitor design.
Collapse
Affiliation(s)
- Catherine L Shelton
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
| | - Audrey L Lamb
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA.
| |
Collapse
|
6
|
Meneely KM, Sundlov JA, Gulick AM, Moran GR, Lamb AL. An Open and Shut Case: The Interaction of Magnesium with MST Enzymes. J Am Chem Soc 2016; 138:9277-93. [PMID: 27373320 PMCID: PMC5029964 DOI: 10.1021/jacs.6b05134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
![]()
The shikimate pathway of bacteria,
fungi, and plants generates
chorismate, which is drawn into biosynthetic pathways that form aromatic
amino acids and other important metabolites, including folates, menaquinone,
and siderophores. Many of the pathways initiated at this branch point
transform chorismate using an MST enzyme. The MST enzymes (menaquinone, siderophore, and tryptophan biosynthetic enzymes) are structurally homologous and magnesium-dependent,
and all perform similar chemical permutations to chorismate by nucleophilic
addition (hydroxyl or amine) at the 2-position of the ring, inducing
displacement of the 4-hydroxyl. The isomerase enzymes release isochorismate
or aminodeoxychorismate as the product, while the synthase enzymes
also have lyase activity that displaces pyruvate to form either salicylate
or anthranilate. This has led to the hypothesis that the isomerase
and lyase activities performed by the MST enzymes are functionally
conserved. Here we have developed tailored pre-steady-state approaches
to establish the kinetic mechanisms of the isochorismate and salicylate
synthase enzymes of siderophore biosynthesis. Our data are centered
on the role of magnesium ions, which inhibit the isochorismate synthase
enzymes but not the salicylate synthase enzymes. Prior structural
data have suggested that binding of the metal ion occludes access
or egress of substrates. Our kinetic data indicate that for the production
of isochorismate, a high magnesium ion concentration suppresses the
rate of release of product, accounting for the observed inhibition
and establishing the basis of the ordered-addition kinetic mechanism.
Moreover, we show that isochorismate is channeled through the synthase
reaction as an intermediate that is retained in the active site by
the magnesium ion. Indeed, the lyase-active enzyme has 3 orders of
magnitude higher affinity for the isochorismate complex relative to
the chorismate complex. Apparent negative-feedback inhibition by ferrous
ions is documented at nanomolar concentrations, which is a potentially
physiologically relevant mode of regulation for siderophore biosynthesis
in vivo.
Collapse
Affiliation(s)
- Kathleen M Meneely
- Department of Molecular Biosciences, University of Kansas , Lawrence, Kansas 66045, United States
| | - Jesse A Sundlov
- Hauptman-Woodward Medical Research Institute , 700 Ellicott Street, Buffalo, New York 14203, United States
| | - Andrew M Gulick
- Hauptman-Woodward Medical Research Institute , 700 Ellicott Street, Buffalo, New York 14203, United States
| | - Graham R Moran
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53201, United States
| | - Audrey L Lamb
- Department of Molecular Biosciences, University of Kansas , Lawrence, Kansas 66045, United States
| |
Collapse
|
7
|
Plach MG, Löffler P, Merkl R, Sterner R. Conversion of anthranilate synthase into isochorismate synthase: implications for the evolution of chorismate-utilizing enzymes. Angew Chem Int Ed Engl 2016; 54:11270-4. [PMID: 26352034 DOI: 10.1002/anie.201505063] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 06/23/2015] [Indexed: 02/06/2023]
Abstract
Chorismate-utilizing enzymes play a vital role in the biosynthesis of metabolites in plants as well as free-living and infectious microorganisms. Among these enzymes are the homologous primary metabolic anthranilate synthase (AS) and secondary metabolic isochorismate synthase (ICS). Both catalyze mechanistically related reactions by using ammonia and water as nucleophiles, respectively. We report that the nucleophile specificity of AS can be extended from ammonia to water by just two amino acid exchanges in a channel leading to the active site. The observed ICS/AS bifunctionality demonstrates that a secondary metabolic enzyme can readily evolve from a primary metabolic enzyme without requiring an initial gene duplication event. In a general sense, these findings add to our understanding how nature has used the structurally predetermined features of enzyme superfamilies to evolve new reactions.
Collapse
Affiliation(s)
- Maximilian G Plach
- Institut für Biophysik und physikalische Biochemie, Universität Regensburg, 93040 Regensburg (Germany)
| | - Patrick Löffler
- Institut für Biophysik und physikalische Biochemie, Universität Regensburg, 93040 Regensburg (Germany)
| | - Rainer Merkl
- Institut für Biophysik und physikalische Biochemie, Universität Regensburg, 93040 Regensburg (Germany)
| | - Reinhard Sterner
- Institut für Biophysik und physikalische Biochemie, Universität Regensburg, 93040 Regensburg (Germany).
| |
Collapse
|
8
|
Plach MG, Löffler P, Merkl R, Sterner R. Umwandlung einer Anthranilatsynthase in eine Isochorismatsynthase: Implikationen für die Evolution von Chorismat-umsetzenden Enzymen. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
9
|
Culbertson JE, Chung DH, Ziebart KT, Espiritu E, Toney MD. Conversion of aminodeoxychorismate synthase into anthranilate synthase with Janus mutations: mechanism of pyruvate elimination catalyzed by chorismate enzymes. Biochemistry 2015; 54:2372-84. [PMID: 25710100 DOI: 10.1021/acs.biochem.5b00013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The central importance of chorismate enzymes in bacteria, fungi, parasites, and plants combined with their absence in mammals makes them attractive targets for antimicrobials and herbicides. Two of these enzymes, anthranilate synthase (AS) and aminodeoxychorismate synthase (ADCS), are structurally and mechanistically similar. The first catalytic step, amination at C2, is common between them, but AS additionally catalyzes pyruvate elimination, aromatizing the aminated intermediate to anthranilate. Despite prior attempts, the conversion of a pyruvate elimination-deficient enzyme into an elimination-proficient one has not been reported. Janus, a bioinformatics method for predicting mutations required to functionally interconvert homologous enzymes, was employed to predict mutations to convert ADCS into AS. A genetic selection on a library of Janus-predicted mutations was performed. Complementation of an AS-deficient strain of Escherichia coli grown on minimal medium led to several ADCS mutants that allow growth in 6 days compared to 2 days for wild-type AS. The purified mutant enzymes catalyze the conversion of chorismate to anthranilate at rates that are ∼50% of the rate of wild-type ADCS-catalyzed conversion of chorismate to aminodeoxychorismate. The residues mutated do not contact the substrate. Molecular dynamics studies suggest that pyruvate elimination is controlled by the conformation of the C2-aminated intermediate. Enzymes that catalyze elimination favor the equatorial conformation, which presents the C2-H to a conserved active site lysine (Lys424) for deprotonation and maximizes stereoelectronic activation. Acid/base catalysis of pyruvate elimination was confirmed in AS and salicylate synthase by showing incorporation of a solvent-derived proton into the pyruvate methyl group and by solvent kinetic isotope effects on pyruvate elimination catalyzed by AS.
Collapse
Affiliation(s)
- Justin E Culbertson
- †Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Dong hee Chung
- †Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| | - Kristin T Ziebart
- ‡Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, United States
| | - Eduardo Espiritu
- §Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Michael D Toney
- †Department of Chemistry, University of California, Davis, Davis, California 95616, United States
| |
Collapse
|
10
|
Xie F, Dai S, Shen J, Ren B, Huang P, Wang Q, Liu X, Zhang B, Dai H, Zhang L. A new salicylate synthase AmS is identified for siderophores biosynthesis in Amycolatopsis methanolica 239(T). Appl Microbiol Biotechnol 2015; 99:5895-905. [PMID: 25586582 DOI: 10.1007/s00253-014-6370-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 12/17/2014] [Accepted: 12/26/2014] [Indexed: 12/14/2022]
Abstract
Siderophores are important for the growth of bacteria or the applications in treatment of iron overload-associated diseases due to the iron-chelating property. Salicylate synthase played a key role in the biosynthesis of some NRPS-derived siderophores by the providing of an iron coordination moiety as the initial building block. A new salicylate synthase, namely AmS, was identified in the biosynthesis pathway of siderophore amychelin in Amycolatopsis methanolica 239(T), since it shunt chorismate, an integrant precursor, from primary to secondary metabolite flow. The amino acid sequence alignment and phylogenetic analysis showed that AmS grouped into a new cluster. In vitro assays of AmS revealed its wide temperature tolerance ranged from 0 to 40 °C and narrow pH tolerant ranged from 7.0 to 9.0. AmS was resistant to organic solvents and non-ionic detergents. Moreover, AmS converted chorismate to salicylate with K m of 129.05 μM, k cat of 2.20 min(-1) at optimal conditions, indicating its low substrate specificity and comparable velocity to reported counterparts (Irp9 and MbtI). These properties of AmS may improve the iron-seizing ability of A. methanolica to compete with its neighbors growing in natural environments. Most importantly, serine and cysteine residues were found to be important for the catalytic activity of AmS. This study presented AmS as a new cluster of salicylate synthase and the reaction mechanism and potential applications of salicylate synthase were highlighted as well.
Collapse
Affiliation(s)
- Feng Xie
- School of Life Sciences, University of Science and Technology of China, No. 443 HuangShan Road, Hefei, 230061, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Meneely KM, Luo Q, Lamb AL. Redesign of MST enzymes to target lyase activity instead promotes mutase and dehydratase activities. Arch Biochem Biophys 2013; 539:70-80. [PMID: 24055536 DOI: 10.1016/j.abb.2013.09.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/10/2013] [Accepted: 09/11/2013] [Indexed: 11/20/2022]
Abstract
The isochorismate and salicylate synthases are members of the MST family of enzymes. The isochorismate synthases establish an equilibrium for the conversion chorismate to isochorismate and the reverse reaction. The salicylate synthases convert chorismate to salicylate with an isochorismate intermediate; therefore, the salicylate synthases perform isochorismate synthase and isochorismate-pyruvate lyase activities sequentially. While the active site residues are highly conserved, there are two sites that show trends for lyase-activity and lyase-deficiency. Using steady state kinetics and HPLC progress curves, we tested the "interchange" hypothesis that interconversion of the amino acids at these sites would promote lyase activity in the isochorismate synthases and remove lyase activity from the salicylate synthases. An alternative, "permute" hypothesis, that chorismate-utilizing enzymes are designed to permute the substrate into a variety of products and tampering with the active site may lead to identification of adventitious activities, is tested by more sensitive NMR time course experiments. The latter hypothesis held true. The variant enzymes predominantly catalyzed chorismate mutase-prephenate dehydratase activities, sequentially generating prephenate and phenylpyruvate, augmenting previously debated (mutase) or undocumented (dehydratase) adventitious activities.
Collapse
Affiliation(s)
- Kathleen M Meneely
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, United States
| | | | | |
Collapse
|
12
|
Domagalski MJ, Tkaczuk KL, Chruszcz M, Skarina T, Onopriyenko O, Cymborowski M, Grabowski M, Savchenko A, Minor W. Structure of isochorismate synthase DhbC from Bacillus anthracis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:956-61. [PMID: 23989140 PMCID: PMC3758140 DOI: 10.1107/s1744309113021246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/30/2013] [Indexed: 06/02/2023]
Abstract
The isochorismate synthase DhbC from Bacillus anthracis is essential for the biosynthesis of the siderophore bacillibactin by this pathogenic bacterium. The structure of the selenomethionine-substituted protein was determined to 2.4 Å resolution using single-wavelength anomalous diffraction. B. anthracis DhbC bears the strongest resemblance to the Escherichia coli isochorismate synthase EntC, which is involved in the biosynthesis of another siderophore, namely enterobactin. Both proteins adopt the characteristic fold of other chorismate-utilizing enzymes, which are involved in the biosynthesis of various products, including siderophores, menaquinone and tryptophan. The conservation of the active-site residues, as well as their spatial arrangement, suggests that these enzymes share a common Mg(2+)-dependent catalytic mechanism.
Collapse
Affiliation(s)
- M. J. Domagalski
- Department of Molecular Physiology and Biological Physics, University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Charlottesville, VA 22908, USA
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
| | - K. L. Tkaczuk
- Department of Molecular Physiology and Biological Physics, University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Charlottesville, VA 22908, USA
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
| | - M. Chruszcz
- Department of Molecular Physiology and Biological Physics, University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Charlottesville, VA 22908, USA
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
| | - T. Skarina
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
- Banting and Best Department of Medical Research, University of Toronto, 112 College Street, Toronto, ON M5G 1L6, Canada
| | - O. Onopriyenko
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
- Banting and Best Department of Medical Research, University of Toronto, 112 College Street, Toronto, ON M5G 1L6, Canada
| | - M. Cymborowski
- Department of Molecular Physiology and Biological Physics, University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Charlottesville, VA 22908, USA
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
| | - M. Grabowski
- Department of Molecular Physiology and Biological Physics, University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Charlottesville, VA 22908, USA
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
| | - A. Savchenko
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
- Banting and Best Department of Medical Research, University of Toronto, 112 College Street, Toronto, ON M5G 1L6, Canada
| | - W. Minor
- Department of Molecular Physiology and Biological Physics, University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Charlottesville, VA 22908, USA
- Center for Structural Genomics of Infectious Diseases (CSGID), USA
| |
Collapse
|
13
|
Meneely KM, Luo Q, Dhar P, Lamb AL. Lysine221 is the general base residue of the isochorismate synthase from Pseudomonas aeruginosa (PchA) in a reaction that is diffusion limited. Arch Biochem Biophys 2013; 538:49-56. [PMID: 23942051 DOI: 10.1016/j.abb.2013.07.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 07/25/2013] [Accepted: 07/28/2013] [Indexed: 01/30/2023]
Abstract
The isochorismate synthase from Pseudomonas aeruginosa (PchA) catalyzes the conversion of chorismate to isochorismate, which is subsequently converted by a second enzyme (PchB) to salicylate for incorporation into the salicylate-capped siderophore pyochelin. PchA is a member of the MST family of enzymes, which includes the structurally homologous isochorismate synthases from Escherichia coli (EntC and MenF) and salicylate synthases from Yersinia enterocolitica (Irp9) and Mycobacterium tuberculosis (MbtI). The latter enzymes generate isochorismate as an intermediate before generating salicylate and pyruvate. General acid-general base catalysis has been proposed for isochorismate synthesis in all five enzymes, but the residues required for the isomerization are a matter of debate, with both lysine221 and glutamate313 proposed as the general base (PchA numbering). This work includes a classical characterization of PchA with steady state kinetic analysis, solvent kinetic isotope effect analysis and by measuring the effect of viscosogens on catalysis. The results suggest that isochorismate production from chorismate by the MST enzymes is the result of general acid-general base catalysis with a lysine as the base and a glutamic acid as the acid, in reverse protonation states. Chemistry is determined to not be rate limiting, favoring the hypothesis of a conformational or binding step as the slow step.
Collapse
Affiliation(s)
- Kathleen M Meneely
- Molecular Biosciences, University of Kansas, Lawrence, KS 66045, United States
| | | | | | | |
Collapse
|
14
|
Culbertson JE, Toney MD. Expression and characterization of PhzE from P. aeruginosa PAO1: aminodeoxyisochorismate synthase involved in pyocyanin and phenazine-1-carboxylate production. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1834:240-6. [PMID: 23099261 DOI: 10.1016/j.bbapap.2012.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 10/04/2012] [Accepted: 10/15/2012] [Indexed: 12/21/2022]
Abstract
PhzE from Pseudomonas aeruginosa catalyzes the first step in the biosynthesis of phenazine-1-carboxylic acid, pyocyanin, and other phenazines, which are virulence factors for Pseudomonas species. The reaction catalyzed converts chorismate into aminodeoxyisochorismate using ammonia supplied by a glutamine amidotransferase domain. It has structural and sequence homology to other chorismate-utilizing enzymes such as anthranilate synthase, isochorismate synthase, aminodeoxychorismate synthase, and salicylate synthase. Like these enzymes, it is Mg(2+) dependent and catalyzes a similar S(N)2" nucleophilic substitution reaction. PhzE catalyzes the addition of ammonia to C2 of chorismate, as does anthranilate synthase, yet unlike anthranilate synthase it does not catalyze elimination of pyruvate from enzyme-bound aminodeoxyisochorismate. Herein, the cloning of the phzE gene, high level expression of active enzyme in E. coli, purification, and kinetic characterization of the enzyme is presented, including temperature and pH dependence. Steady-state kinetics give K(chorismate)=20±4μM, K(Mg)(2+)=294±22μM, K(L-gln)=11±1mM, and k(cat)=2.2±0.2s(-1) for a random kinetic mechanism. PhzE can use NH(4)(+) as an alternative nucleophile, while Co(2+) and Mn(2+) are alternative divalent metals.
Collapse
Affiliation(s)
- Justin E Culbertson
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | | |
Collapse
|
15
|
Camara D, Bisanz C, Barette C, Van Daele J, Human E, Barnard B, Van der Straeten D, Stove CP, Lambert WE, Douce R, Maréchal E, Birkholtz LM, Cesbron-Delauw MF, Dumas R, Rébeillé F. Inhibition of p-aminobenzoate and folate syntheses in plants and apicomplexan parasites by natural product rubreserine. J Biol Chem 2012; 287:22367-76. [PMID: 22577137 DOI: 10.1074/jbc.m112.365833] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Glutamine amidotransferase/aminodeoxychorismate synthase (GAT-ADCS) is a bifunctional enzyme involved in the synthesis of p-aminobenzoate, a central component part of folate cofactors. GAT-ADCS is found in eukaryotic organisms autonomous for folate biosynthesis, such as plants or parasites of the phylum Apicomplexa. Based on an automated screening to search for new inhibitors of folate biosynthesis, we found that rubreserine was able to inhibit the glutamine amidotransferase activity of the plant GAT-ADCS with an apparent IC(50) of about 8 μM. The growth rates of Arabidopsis thaliana, Toxoplasma gondii, and Plasmodium falciparum were inhibited by rubreserine with respective IC(50) values of 65, 20, and 1 μM. The correlation between folate biosynthesis and growth inhibition was studied with Arabidopsis and Toxoplasma. In both organisms, the folate content was decreased by 40-50% in the presence of rubreserine. In both organisms, the addition of p-aminobenzoate or 5-formyltetrahydrofolate in the external medium restored the growth for inhibitor concentrations up to the IC(50) value, indicating that, within this range of concentrations, rubreserine was specific for folate biosynthesis. Rubreserine appeared to be more efficient than sulfonamides, antifolate drugs known to inhibit the invasion and proliferation of T. gondii in human fibroblasts. Altogether, these results validate the use of the bifunctional GAT-ADCS as an efficient drug target in eukaryotic cells and indicate that the chemical structure of rubreserine presents interesting anti-parasitic (toxoplasmosis, malaria) potential.
Collapse
Affiliation(s)
- Djeneb Camara
- Laboratoire de Physiologie Cellulaire Végétale, Commissariat à l'Energie Atomique/CNRS UMR5168/INRA USC1200/Université Joseph Fourier Grenoble I, Institut de Recherches en Technologies et Sciences pour le Vivant, F-38054 Grenoble, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Ferrer S, Ruiz-Pernía J, Martí S, Moliner V, Tuñón I, Bertrán J, Andrés J. Hybrid schemes based on quantum mechanics/molecular mechanics simulations goals to success, problems, and perspectives. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2012; 85:81-142. [PMID: 21920322 DOI: 10.1016/b978-0-12-386485-7.00003-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The development of characterization techniques, advanced synthesis methods, as well as molecular modeling has transformed the study of systems in a well-established research field. The current research challenges in biocatalysis and biotransformation evolve around enzyme discovery, design, and optimization. How can we find or create enzymes that catalyze important synthetic reactions, even reactions that may not exist in nature? What is the source of enzyme catalytic power? To answer these and other related questions, the standard strategies have evolved from trial-and-error methodologies based on chemical knowledge, accumulated experience, and common sense into a clearly multidisciplinary science that allows one to reach the molecular design of tailor-made enzyme catalysts. This is even more so when one refers to enzyme catalysts, for which the detailed structure and composition are known and can be manipulated to introduce well-defined residues which can be implicated in the chemical rearrangements taking place in the active site. The methods and techniques of theoretical and computational chemistry are becoming more and more important in both understanding the fundamental biological roles of enzymes and facilitating their utilization in biotechnology. Improvement of the catalytic function of enzymes is important from scientific and industrial viewpoints, and to put this fact in the actual perspective as well as the potentialities, we recommend the very recent report of Sanderson [Sanderson, K. (2011). Chemistry: enzyme expertise. Nature 471, 397.]. Great fundamental advances have been made toward the ab initio design of enzyme catalysts based on molecular modeling. This has been based on the molecular mechanistic knowledge of the reactions to be catalyzed, together with the development of advanced synthesis and characterization techniques. The corresponding molecular mechanism can be studied by means of powerful quantum chemical calculations. The catalytic active site can be optimized to improve the transition state analogues (TSA) and to enhance the catalytic activity, even improve the active site to favor a desired direction of some promiscuous enzymes. In this chapter, we give a brief introduction, the state of the art, and future prospects and implications of enzyme design. Current computational tools to assist experimentalists for the design and engineering of proteins with desired catalytic properties are described. The interplay between enzyme design, molecular simulations, and experiments will be presented to emphasize the interdisciplinary nature of this research field. This text highlights the recent advances and examples selected from our laboratory are shown, of how the applications of these tools are a first attempt to de novo design of protein active sites. Identification of neutral/advantageous/deleterious mutation platforms can be exploited to penetrate some of Nature's closely guarded secrets of chemical reactivity. In this chapter, we give a brief introduction, the state of the art, and future prospects and implications of enzyme design. The first part describes briefly how the molecular modeling is carried out. Then, we discuss the requirements of hybrid quantum mechanical/molecular mechanics molecular dynamics (QM/MM MD) simulations, analyzing what are the basis of these theoretical methodologies, how we can use them with a view to its application in the study of enzyme catalysis, and what are the best methodologies for assessing its catalytic potential. In the second part, we focus on some selected examples, taking as a common guide the chorismate to prephenate rearrangement, studying the corresponding molecular mechanism in vacuo, in solution and in an enzyme environment. In addition, examples involving catalytic antibodies (CAs) and promiscuous enzymes will be presented. Finally, a special emphasis is made to provide some hints about the logical evolution that can be anticipated in this research field. Moreover, it helps in understanding the open directions in this area of knowledge and highlights the importance of computational approaches in discovering specific drugs and the impact on the rational design of tailor-made enzymes.
Collapse
Affiliation(s)
- Silvia Ferrer
- Departamento de Química Física y Analítica, Universitat Jaume I, Castellón, Spain
| | | | | | | | | | | | | |
Collapse
|
17
|
Walsh CT, Haynes SW, Ames BD. Aminobenzoates as building blocks for natural productassembly lines. Nat Prod Rep 2012; 29:37-59. [DOI: 10.1039/c1np00072a] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
18
|
Ferrer S, Martí S, Moliner V, Tuñón I, Bertrán J. Understanding the different activities of highly promiscuous MbtI by computational methods. Phys Chem Chem Phys 2012; 14:3482-9. [DOI: 10.1039/c2cp23149b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
|
19
|
Abstract
One of the fundamental questions of enzymology is how catalytic power is derived. This review focuses on recent developments in the structure--function relationships of chorismate-utilizing enzymes involved in siderophore biosynthesis to provide insight into the biocatalysis of pericyclic reactions. Specifically, salicylate synthesis by the two-enzyme pathway in Pseudomonas aeruginosa is examined. The isochorismate-pyruvate lyase is discussed in the context of its homologues, the chorismate mutases, and the isochorismate synthase is compared to its homologues in the MST family (menaquinone, siderophore, or tryptophan biosynthesis) of enzymes. The tentative conclusion is that the activities observed cannot be reconciled by inspection of the active site participants alone. Instead, individual activities must arise from unique dynamic properties of each enzyme that are tuned to promote specific chemistries.
Collapse
Affiliation(s)
- Audrey L Lamb
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, United States.
| |
Collapse
|
20
|
Dawson A, Fyfe PK, Gillet F, Hunter WN. Exploiting the high-resolution crystal structure of Staphylococcus aureus MenH to gain insight into enzyme activity. BMC STRUCTURAL BIOLOGY 2011; 11:19. [PMID: 21513522 PMCID: PMC3097144 DOI: 10.1186/1472-6807-11-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 04/22/2011] [Indexed: 11/23/2022]
Abstract
Background MenH (2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase) is a key enzyme in the biosynthesis of menaquinone, catalyzing an unusual 2,5-elimination of pyruvate from 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexadiene-1-carboxylate. Results The crystal structure of Staphylococcus aureus MenH has been determined at 2 Å resolution. In the absence of a complex to inform on aspects of specificity a model of the enzyme-substrate complex has been used in conjunction with previously published kinetic analyses, site-directed mutagenesis studies and comparisons with orthologues to investigate the structure and reactivity of MenH. Conclusions The overall basic active site displays pronounced hydrophobic character on one side and these properties complement those of the substrate. A complex network of hydrogen bonds involving well-ordered water molecules serves to position key residues participating in the recognition of substrate and subsequent catalysis. We propose a proton shuttle mechanism, reliant on a catalytic triad consisting of Ser89, Asp216 and His243. The reaction is initiated by proton abstraction from the substrate by an activated Ser89. The propensity to form a conjugated system provides the driving force for pyruvate elimination. During the elimination, a methylene group is converted to a methyl and we judge it likely that His243 provides a proton, previously acquired from Ser89 for that reduction. A conformational change of the protonated His243 may be encouraged by the presence of an anionic intermediate in the active site.
Collapse
Affiliation(s)
- Alice Dawson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | | | | | | |
Collapse
|
21
|
Camara D, Richefeu-Contesto C, Gambonnet B, Dumas R, Rébeillé F. The synthesis of pABA: Coupling between the glutamine amidotransferase and aminodeoxychorismate synthase domains of the bifunctional aminodeoxychorismate synthase from Arabidopsis thaliana. Arch Biochem Biophys 2011; 505:83-90. [DOI: 10.1016/j.abb.2010.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 09/09/2010] [Accepted: 09/09/2010] [Indexed: 10/19/2022]
|
22
|
|