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Zhang Z, Long M, Zheng N, Deng Y, Wang Q, Osire T, Xia X. Redesign of γ-glutamyl transpeptidase from Bacillus subtilis for high-level production of L-theanine by cavity topology engineering. Appl Microbiol Biotechnol 2023; 107:3551-3564. [PMID: 37099056 DOI: 10.1007/s00253-023-12544-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 04/12/2023] [Accepted: 04/16/2023] [Indexed: 04/27/2023]
Abstract
L-Theanine is a multifunctional nonprotein amino acid found naturally in tea leaves. It has been developed as a commercial product for a wide range of applications in the food, pharmaceutical, and healthcare industries. However, L-theanine production catalyzed by γ-glutamyl transpeptidase (GGT) is limited by the low catalytic efficiency and specificity of this class of enzymes. Here, we developed a strategy for cavity topology engineering (CTE) based on the cavity geometry of GGT from B. subtilis 168 (CGMCC 1.1390) to obtain an enzyme with high catalytic activity and applied it to the synthesis of L-theanine. Three potential mutation sites, M97, Y418, and V555, were identified using the internal cavity as a probe, and residues G, A, V, F, Y, and Q, which may affect the shape of the cavity, were obtained directly by computer statistical analysis without energy calculations. Finally, 35 mutants were obtained. The optimal mutant Y418F/M97Q showed a 4.8-fold improvement in catalytic activity and a 25.6-fold increase in catalytic efficiency. The recombinant enzyme Y418F/M97Q exhibited a high space-time productivity of 15.4 g L-1 h-1 by whole-cell synthesis in a 5 L bioreactor, which was one of the highest concentrations reported so far at 92.4 g L-1. Overall, this strategy is expected to enhance the enzymatic activity associated with the synthesis of L-theanine and its derivatives.Key points • Cavity topology engineering was used to modify the GGT for L-theanine biocatalysis. • The catalytic efficiency of GGT was increased by 25.6-fold. • Highest productivity of L-theanine reached 15.4 g L -1 h-1 (92.4 g L-1) in a 5 L bioreactor.
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Affiliation(s)
- Zehua Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Mengfei Long
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Nan Zheng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Yu Deng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Qiong Wang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Tolbert Osire
- Faculty of Biology, Shenzhen MSU-BIT University, Shenzhen, 518172, Guangdong, China
| | - Xiaole Xia
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
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2
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Chi MC, Lu BY, Huang YF, Wang SW, Lin MG, Wang TF. Effects of Sodium Dodecyl Sulfate on the Enzyme Catalysis and Conformation of a Recombinant γ-Glutamyltranspeptidase from Bacillus licheniformis. Protein J 2023; 42:64-77. [PMID: 36739340 DOI: 10.1007/s10930-023-10095-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2023] [Indexed: 02/06/2023]
Abstract
The study of interactions between proteins and surfactants is of relevance in a diverse range of applications including food, enzymatic detergent formulation, and drug delivery. In spite of sodium dodecyl sulfate (SDS)-induced unfolding has been studied in detail at the protein level, deciphering the conformation-activity relationship of a recombinant γ-glutamyltranspeptidase (BlrGGT) from Bacillus licheniformis remains important to understand how the transpeptidase activity is related to its conformation. In this study, we examined the enzyme catalysis and conformational transition of BlrGGT in the presence of SDS. Enzymatic assays showed that the transpeptidase activity of BlrGGT was greatly affected by SDS in a concentration-dependent manner with approximately 90% inactivation at 6 mM. Native polyacrylamide gel electrophoresis of SDS-treated samples clearly revealed that the heterodimeric enzyme was apparently dissociated into two different subunits at concentrations above 2 mM. The study of enzyme kinetics showed that SDS can act as a mixed-type inhibitor to reduce the catalytic efficiency of BlrGGT. Moreover, the t1/2 value of the enzyme at 55 °C was greatly reduced from 495.1 min to 7.4 min in the presence of 1 mM SDS. The I3/I1 ratio of pyrene excimer fluorescence emission changed around 3.7 mM SDS in the absence of BlrGGT and the inflection point of enzyme samples was reduced to less than 2.7 mM. The Far-UV CD spectrum of the native enzyme had two negative peaks at 208 and 222 nm, respectively; however, both negative peaks increased in magnitude with increasing SDS concentration and reached maximal values at above 4.0 mM. The intrinsic fluorescence spectra of tryptophan further demonstrated that the SDS-induced enzyme conformational transition occurred at approximately 5.1 mM. Tween 20 significantly suppressed the interaction of BlrGGT with SDS by forming mixed micelles at a molar ratio of 1.0. Taken together, this study definitely promotes our better understanding of the relationship between the conformation and catalysis of BlrGGT.
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Affiliation(s)
- Meng-Chun Chi
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Bo-Yuan Lu
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Yu-Fen Huang
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Shih-Wei Wang
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Min-Guan Lin
- Institute of Molecular Biology, Academia Sinica, Nangang District, Taipei City, 11529, Taiwan
| | - Tzu-Fan Wang
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan.
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3
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Loch JI, Klonecka A, Kądziołka K, Bonarek P, Barciszewski J, Imiolczyk B, Brzezinski K, Gilski M, Jaskolski M. Structural and biophysical studies of new L-asparaginase variants: lessons from random mutagenesis of the prototypic Escherichia coli Ntn-amidohydrolase. Acta Crystallogr D Struct Biol 2022; 78:911-926. [PMID: 35775990 PMCID: PMC9248843 DOI: 10.1107/s2059798322005691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/25/2022] [Indexed: 11/11/2022] Open
Abstract
This work reports the results of random mutagenesis of the Escherichia coli class 2 L-asparaginase EcAIII belonging to the Ntn-hydrolase family. New variants of EcAIII were studied using structural, biophysical and bioinformatic methods. Activity tests revealed that the L-asparaginase activity is abolished in all analyzed mutants with the absence of Arg207, but some of them retained the ability to undergo the autoproteolytic maturation process. The results of spectroscopic studies and the determined crystal structures showed that the EcAIII fold is flexible enough to accept different types of mutations; however, these mutations may have a diverse impact on the thermal stability of the protein. The conclusions from the experiments are grouped into six lessons focused on (i) the adaptation of the EcAIII fold to new substitutions, (ii) the role of Arg207 in EcAIII activity, (iii) a network of residues necessary for autoprocessing, (iv) the complexity of the autoprocessing reaction, (v) the conformational changes observed in enzymatically inactive variants and (vi) the cooperativity of the EcAIII dimer subunits. Additionally, the structural requirements (pre-maturation checkpoints) that are necessary for the initiation of the autocleavage of Ntn-hydrolases have been classified. The findings reported in this work provide useful hints that should be considered before planning enzyme-engineering experiments aimed at the design of proteins for therapeutic applications. This is especially important for L-asparaginases that can be utilized in leukemia therapy, as alternative therapeutics are urgently needed to circumvent the severe side effects associated with the currently used enzymes.
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4
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Lin LL, Lu BY, Chi MC, Huang YF, Lin MG, Wang TF. Activation and thermal stabilization of a recombinant γ-glutamyltranspeptidase from Bacillus licheniformis ATCC 27811 by monovalent cations. Appl Microbiol Biotechnol 2022; 106:1991-2006. [PMID: 35230495 DOI: 10.1007/s00253-022-11836-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 02/08/2022] [Accepted: 02/12/2022] [Indexed: 12/27/2022]
Abstract
The regulation of enzyme activity through complexation with certain metal ions plays an important role in many biological processes. In addition to divalent metals, monovalent cations (MVCs) frequently function as promoters for efficient biocatalysis. Here, we examined the effect of MVCs on the enzymatic catalysis of a recombinant γ-glutamyltranspeptidase (BlrGGT) from Bacillus licheniformis ATCC 27,811 and the application of a metal-activated enzyme to L-theanine synthesis. The transpeptidase activity of BlrGGT was enhanced by Cs+ and Na+ over a broad range of concentrations with a maximum of 200 mM. The activation was essentially independent of the ionic radius, but K+ contributed the least to enhancing the catalytic efficiency. The secondary structure of BlrGGT remained mostly unchanged in the presence of different concentrations of MVCs, but there was a significant change in its tertiary structure under the same conditions. Compared with the control, the half-life (t1/2) of the Cs+-enriched enzyme at 60 and 65 °C was shown to increase from 16.3 and 4.0 min to 74.5 and 14.3 min, respectively. The simultaneous addition of Cs+ and Mg2+ ions exerted a synergistic effect on the activation of BlrGGT. This was adequately reflected by an improvement in the conversion of substrates to L-theanine by 3.3-15.1% upon the addition of 200 mM MgCl2 into a reaction mixture comprising the freshly desalted enzyme (25 μg/mL), 250 mM L-glutamine, 600 mM ethylamine, 200 mM each of the MVCs, and 50 mM borate buffer (pH 10.5). Taken together, our results provide interesting insights into the complexation of MVCs with BlrGGT and can therefore be potentially useful to the biocatalytic production of naturally occurring γ-glutamyl compounds. KEY POINTS: • The transpeptidase activity of B. licheniformis γ-glutamyltranspeptidase can be activated by monovalent cations. • The thermal stability of the enzyme was profoundly increased in the presence of 200 mM Cs+. • The simultaneous addition of Cs+and Mg2+ions to the reaction mixture improves L-theanine production.
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Affiliation(s)
- Long-Liu Lin
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Bo-Yuan Lu
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Meng-Chun Chi
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Yu-Fen Huang
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan
| | - Min-Guan Lin
- Institute of Molecular Biology, Academia Sinica, Nangang District, Taipei City, 11529, Taiwan
| | - Tzu-Fan Wang
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City, 60004, Taiwan.
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5
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Saini M, Kalra S, Kaushik JK, Gupta R. Functional characterization of the extra sequence in the large subunit of γ-glutamyl transpeptidase from Bacillus atrophaeus: Role in autoprocessing and activity. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Saini M, Kashyap A, Bindal S, Saini K, Gupta R. Bacterial Gamma-Glutamyl Transpeptidase, an Emerging Biocatalyst: Insights Into Structure-Function Relationship and Its Biotechnological Applications. Front Microbiol 2021; 12:641251. [PMID: 33897647 PMCID: PMC8062742 DOI: 10.3389/fmicb.2021.641251] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 02/15/2021] [Indexed: 12/16/2022] Open
Abstract
Gamma-glutamyl transpeptidase (GGT) enzyme is ubiquitously present in all life forms and plays a variety of roles in diverse organisms. Higher eukaryotes mainly utilize GGT for glutathione degradation, and mammalian GGTs have implications in many physiological disorders also. GGTs from unicellular prokaryotes serve different physiological functions in Gram-positive and Gram-negative bacteria. In the present review, the physiological significance of bacterial GGTs has been discussed categorizing GGTs from Gram-negative bacteria like Escherichia coli as glutathione degraders and from pathogenic species like Helicobacter pylori as virulence factors. Gram-positive bacilli, however, are considered separately as poly-γ-glutamic acid (PGA) degraders. The structure-function relationship of the GGT is also discussed mainly focusing on the crystallization of bacterial GGTs along with functional characterization of conserved regions by site-directed mutagenesis that unravels molecular aspects of autoprocessing and catalysis. Only a few crystal structures have been deciphered so far. Further, different reports on heterologous expression of bacterial GGTs in E. coli and Bacillus subtilis as hosts have been presented in a table pointing toward the lack of fermentation studies for large-scale production. Physicochemical properties of bacterial GGTs have also been described, followed by a detailed discussion on various applications of bacterial GGTs in different biotechnological sectors. This review emphasizes the potential of bacterial GGTs as an industrial biocatalyst relevant to the current switch toward green chemistry.
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Affiliation(s)
| | | | | | | | - Rani Gupta
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
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7
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Xu L, Han F, Zhang X, Yu Q. Ultrasound enhanced biosynthesis of L-theanine from L-glutamine and ethylamine by recombinant γ-glutamyltranspeptidase. BIORESOURCE TECHNOLOGY 2020; 307:123251. [PMID: 32245672 DOI: 10.1016/j.biortech.2020.123251] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/21/2020] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
A mutant library of the key amino acid residue site E387 in γ-glutamyltranspeptidase was constructed to screen the mutant enzymes with significantly improved thermal stability (E387Q). The reaction temperature of the mutant enzyme (E387Q) was 10℃ higher than that of the parent enzyme. Ultrasound-assisted synthesis of L-theanine by γ-glutamyltranspeptidase was investigated. The effects of ultrasonic power, reaction pH and substrate concentration on the enzymatic synthesis of L-theanine were studied by the response surface method. The results showed that the optimal process conditions are ultrasonic power of 100 W, reaction pH of 9, substrate L-glutamine concentration of 120 mmol/L, reaction temperature of 45℃, and L-theanine yield of 89.1%. The yield of L-theanine is 2.61 times higher than that obtained without ultrasound. Ultrasound can significantly promote the synthesis of L-theanine by γ-glutamyltranspeptidase.
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Affiliation(s)
- Lisheng Xu
- Department of Life and Food Science, Suzhou University, Suzhou 234000, China.
| | - Fangkai Han
- Department of Life and Food Science, Suzhou University, Suzhou 234000, China
| | - Xingtao Zhang
- Department of Life and Food Science, Suzhou University, Suzhou 234000, China
| | - Qiaoling Yu
- Department of Life and Food Science, Suzhou University, Suzhou 234000, China
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8
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Abstract
The mercapturic acid pathway is a major route for the biotransformation of xenobiotic and endobiotic electrophilic compounds and their metabolites. Mercapturic acids (N-acetyl-l-cysteine S-conjugates) are formed by the sequential action of the glutathione transferases, γ-glutamyltransferases, dipeptidases, and cysteine S-conjugate N-acetyltransferase to yield glutathione S-conjugates, l-cysteinylglycine S-conjugates, l-cysteine S-conjugates, and mercapturic acids; these metabolites constitute a "mercapturomic" profile. Aminoacylases catalyze the hydrolysis of mercapturic acids to form cysteine S-conjugates. Several renal transport systems facilitate the urinary elimination of mercapturic acids; urinary mercapturic acids may serve as biomarkers for exposure to chemicals. Although mercapturic acid formation and elimination is a detoxication reaction, l-cysteine S-conjugates may undergo bioactivation by cysteine S-conjugate β-lyase. Moreover, some l-cysteine S-conjugates, particularly l-cysteinyl-leukotrienes, exert significant pathophysiological effects. Finally, some enzymes of the mercapturic acid pathway are described as the so-called "moonlighting proteins," catalytic proteins that exert multiple biochemical or biophysical functions apart from catalysis.
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Affiliation(s)
- Patrick E Hanna
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - M W Anders
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
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9
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Noguera ME, Jakoncic J, Ermácora MR. High-resolution structure of intramolecularly proteolyzed human mucin-1 SEA domain. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140361. [PMID: 31923589 DOI: 10.1016/j.bbapap.2020.140361] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 01/26/2023]
Abstract
SEA domains are ubiquitous in large proteins associated with highly glycosylated environments. Certain SEA domains undergo intramolecular proteolysis involving a nucleophilic attack of a serine hydroxyl group on the preceding glycine carbonyl. The mucin-1 (MUC1) SEA domain has been extensively investigated as a model of intramolecular proteolysis. Since neither a general base, a general acid, nor an oxyanion hole could be identified in MUC1 SEA, it has been suggested that proteolysis is accelerated by a non-planarity of the scissile peptide bond imposed by protein folding. A reactant distorted peptide bond has been also invoked to explain the autoproteolysis of several unrelated proteins. However, the only evidence of peptide distortion in MUC1 SEA stems from molecular dynamic simulations of the reactant modeled upon a single NMR structure of the cleaved product. We report the first high-resolution X-ray structure of cleaved MUC1 SEA. Structural comparison with uncleaved SEA domains suggests that the number of residues evolutionarily inserted in the cleaved loop of MUC1 SEA precludes the formation of a properly hydrogen-bonded beta turn. By sequence analysis, we show that this conformational frustration is shared by all known cleaved SEA domains. In addition, alternative conformations of the uncleaved precursor could be modeled in which the scissile peptide bond is planar. The implications of these structures for autoproteolysis are discussed in the light of the previous research on autoproteolysis.
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Affiliation(s)
- Martín E Noguera
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Argentina; Instituto de Química y Físico-Química Biológicas, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Jean Jakoncic
- Photon Science Directorate, Brookhaven National Laboratory, Upton, New York, United States
| | - Mario R Ermácora
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Argentina; Grupo de Biología Estructural y Biotecnología, IMBICE, CONICET, Universidad Nacional de Quilmes,Argentina.
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10
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Enzymatic synthesis of L-theanine from L-glutamine and ethylamine by Bacillus licheniformis γ-glutamyltranspeptidase and its mutants specialized in transpeptidase activity. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2019. [DOI: 10.1016/j.bcab.2019.101393] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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11
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Mutational Analysis of a Highly Conserved PLSSMXP Sequence in the Small Subunit of Bacillus licheniformis γ-Glutamyltranspeptidase. Biomolecules 2019; 9:biom9090508. [PMID: 31546955 PMCID: PMC6769717 DOI: 10.3390/biom9090508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 01/13/2023] Open
Abstract
A highly conserved 458PLSSMXP464 sequence in the small subunit (S-subunit) of an industrially important Bacillus licheniformis γ-glutamyltranspeptidase (BlGGT) was identified by sequence alignment. Molecular structures of the precursor mimic and the mature form of BlGGT clearly reveal that this peptide sequence is in close spatial proximity to the self-processing and catalytic sites of the enzyme. To probe the role of this conserved sequence, ten mutant enzymes of BlGGT were created through a series of deletion and alanine-scanning mutagenesis. SDS-PAGE and densitometric analyses showed that the intrinsic ability of BlGGT to undergo autocatalytic processing was detrimentally affected by the deletion-associated mutations. However, loss of self-activating capacity was not obviously observed in most of the Ala-replacement mutants. The Ala-replacement mutants had a specific activity comparable to or greater than that of the wild-type enzyme; conversely, all deletion mutants completely lost their enzymatic activity. As compared with BlGGT, S460A and S461S showed greatly enhanced kcat/Km values by 2.73- and 2.67-fold, respectively. The intrinsic tryptophan fluorescence and circular dichroism spectral profiles of Ala-replacement and deletion mutants were typically similar to those of BlGGT. However, heat and guanidine hydrochloride-induced unfolding transitions of the deletion-associated mutant proteins were severely reduced as compared with the wild-type enzyme. The predictive mutant models suggest that the microenvironments required for both self-activation and catalytic reaction of BlGGT can be altered upon mutations.
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12
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Ketogenic Diet and Microbiota: Friends or Enemies? Genes (Basel) 2019; 10:genes10070534. [PMID: 31311141 PMCID: PMC6678592 DOI: 10.3390/genes10070534] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 07/06/2019] [Accepted: 07/10/2019] [Indexed: 12/12/2022] Open
Abstract
Over the last years, a growing body of evidence suggests that gut microbial communities play a fundamental role in many aspects of human health and diseases. The gut microbiota is a very dynamic entity influenced by environment and nutritional behaviors. Considering the influence of such a microbial community on human health and its multiple mechanisms of action as the production of bioactive compounds, pathogens protection, energy homeostasis, nutrients metabolism and regulation of immunity, establishing the influences of different nutritional approach is of pivotal importance. The very low carbohydrate ketogenic diet is a very popular dietary approach used for different aims: from weight loss to neurological diseases. The aim of this review is to dissect the complex interactions between ketogenic diet and gut microbiota and how this large network may influence human health.
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Massone M, Calvio C, Rabuffetti M, Speranza G, Morelli CF. Effect of the inserted active-site-covering lid loop on the catalytic activity of a mutant B. subtilis γ-glutamyltransferase (GGT). RSC Adv 2019; 9:34699-34709. [PMID: 35530678 PMCID: PMC9073855 DOI: 10.1039/c9ra05941e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/11/2019] [Indexed: 11/24/2022] Open
Abstract
γ-Glutamylpeptides are compounds derived from the acylation of an amino acid or a short peptide by the γ-carboxyl carbon of the side chain of glutamic acid. Due to their altered chemico-physical and organoleptic properties, they may be interesting substitutes or precursors of parent compounds used in pharmaceutical, dietetic and cosmetic formulations. Some of them are naturally occurring flavor enhancers or are endowed with biological activities. Enzymatic approaches to the synthesis of γ-glutamyl derivatives based on the use of γ-glutamyltransferases (GGTs, EC 2.3.2.2) have been proposed, which should be able to alleviate the problems connected with the troublesome and low-yielding extraction from natural sources or the non-economical chemical synthesis, which requires protection/deprotection steps. With the aim of overcoming the current limitations in the use of GGTs as biocatalysts, a mutant GGT was investigated. The mutant GGT was obtained by inserting the active-site-covering lid loop of the E. coli GGT onto the structure of B. subtilis GGT. With respect to the wild-type enzyme, the mutant showed a more demanding substrate specificity and a low hydrolase activity. These results represent an attempt to correlate the structural features of a GGT to its different activities. However, the ability of the mutant enzyme to catalyze the subsequent addition of several γ-glutamyl units, inherited by the parent B. subtilis GGT, still represents a limitation to its full application as a biocatalyst for preparative purposes. A mutant γ-glutamyltransferase with improve transpeptidase activity was obtained by inserting the active site-covering lid loop on an enzyme naturally lacking it.![]()
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Affiliation(s)
- Michela Massone
- Department of Chemistry
- Università degli Studi di Milano
- 20133 Milano
- Italy
| | - Cinzia Calvio
- Department of Biology and Biotechnology
- Università degli Studi di Pavia
- 27100 Pavia
- Italy
| | - Marco Rabuffetti
- Dipartimento di Scienze per gli Alimenti, la Nutrizione e l’Ambiente
- Università degli Studi di Milano
- 20133 Milano
- Italy
| | - Giovanna Speranza
- Department of Chemistry
- Università degli Studi di Milano
- 20133 Milano
- Italy
- Istituto di Scienze e Tecnologie Molecolari (INSTM)
| | - Carlo F. Morelli
- Department of Chemistry
- Università degli Studi di Milano
- 20133 Milano
- Italy
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14
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Calvio C, Romagnuolo F, Vulcano F, Speranza G, Morelli CF. Evidences on the role of the lid loop of γ-glutamyltransferases (GGT) in substrate selection. Enzyme Microb Technol 2018; 114:55-62. [DOI: 10.1016/j.enzmictec.2018.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/28/2018] [Accepted: 04/02/2018] [Indexed: 12/15/2022]
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15
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Lisheng X, Guizhen G, Xingtao Z, Mengting W. Enzymatic synthesis of γ-glutamylmethylamide from L-glutamylhydrazine and methylamine catalysed by immobilized recombinant γ-glutamyltranspeptidase. BIOCATAL BIOTRANSFOR 2018. [DOI: 10.1080/10242422.2018.1459577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Xu Lisheng
- Department of Life and Food Science, Suzhou University, Suzhou, China
| | - Gao Guizhen
- Department of Life and Food Science, Suzhou University, Suzhou, China
| | - Zhang Xingtao
- Department of Life and Food Science, Suzhou University, Suzhou, China
| | - Wang Mengting
- Department of Life and Food Science, Suzhou University, Suzhou, China
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16
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Functional role of the conserved glycine residues, Gly481 and Gly482, of the γ-glutamyltranspeptidase from Bacillus licheniformis. Int J Biol Macromol 2017; 109:1182-1188. [PMID: 29162462 DOI: 10.1016/j.ijbiomac.2017.11.116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 01/17/2023]
Abstract
Six mutants bearing single amino acid substitutions in the small subunit of Bacillus licheniformis γ-glutamyltranspeptudase (BlGGT) have been constructed by site-directed mutagenesis. The resultant enzymes were overexpressed in Escherichia coli and purified by affinity chromatography for biochemical and biophysical characterizations. Replacing Gly481 by either Ala or Glu did affect both autocatalytic processing and catalytic activity of the enzyme, but the substitution of this residue to arginine resulted in an unprocessed enzyme with insignificant catalytic activity. The replacement of another conserved glycine residue, Gly482, by either Ala or Glu caused a significant change in the functional integrity of the enzyme. Moreover, the mutation of Gly482 to arginine led to a marked reduction in the autocatalytic processing. Structural analyses revealed that the fluorescence and circular dichroism properties of mutant proteins were basically consistent with those of BlGGT. However, guanidine hydrochloride (GdnHCl)-induced transitions of most mutants were profoundly reduced in comparison with that of wild-type enzyme. Molecular modeling suggests that the conserved Gly481 and Gly482 residues of BlGGT are located at critical positions to create an environment suitable for both autoprocessing and catalytic reactions.
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Zhong G, Zhao Q, Zhang Q, Liu W. 4-alkyl-L-(Dehydro)proline biosynthesis in actinobacteria involves N-terminal nucleophile-hydrolase activity of γ-glutamyltranspeptidase homolog for C-C bond cleavage. Nat Commun 2017; 8:16109. [PMID: 28706296 PMCID: PMC5519988 DOI: 10.1038/ncomms16109] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 05/30/2017] [Indexed: 12/22/2022] Open
Abstract
γ-Glutamyltranspeptidases (γ-GTs), ubiquitous in glutathione metabolism for γ-glutamyl transfer/hydrolysis, are N-terminal nucleophile (Ntn)-hydrolase fold proteins that share an autoproteolytic process for self-activation. γ-GT homologues are widely present in Gram-positive actinobacteria where their Ntn-hydrolase activities, however, are not involved in glutathione metabolism. Herein, we demonstrate that the formation of 4-Alkyl-L-(dehydro)proline (ALDP) residues, the non-proteinogenic α-amino acids that serve as vital components of many bioactive metabolites found in actinobacteria, involves unprecedented Ntn-hydrolase activity of γ-GT homologue for C–C bond cleavage. The related enzymes share a key Thr residue, which acts as an internal nucleophile for protein hydrolysis and then as a newly released N-terminal nucleophile for carboxylate side-chain processing likely through the generation of an oxalyl-Thr enzyme intermediate. These findings provide mechanistic insights into the biosynthesis of various ALDP residues/associated natural products, highlight the versatile functions of Ntn-hydrolase fold proteins, and particularly generate interest in thus far less-appreciated γ-GT homologues in actinobacteria. γ-Glutamyltranspeptidases in gram-positive bacteria are not involved in glutathione metabolism, as their counterparts in eukaryotes and gram-negative bacteria. Here, the authors show that in Actinobacteria they catalyse the unusual cleavage of a C–C bond for the biosynthesis of non-proteinogenic amino acids.
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Affiliation(s)
- Guannan Zhong
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Qunfei Zhao
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.,State Key Laboratory of Microbial Metabolism, School of Life Science &Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Qinglin Zhang
- Huzhou Center of Bio-Synthetic Innovation, 1366 Hongfeng Road, Huzhou 313000, China
| | - Wen Liu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.,State Key Laboratory of Microbial Metabolism, School of Life Science &Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.,Huzhou Center of Bio-Synthetic Innovation, 1366 Hongfeng Road, Huzhou 313000, China
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Kumari S, Pal RK, Gupta R, Goel M. High Resolution X-ray Diffraction Dataset for Bacillus licheniformis Gamma Glutamyl Transpeptidase-acivicin complex: SUMO-Tag Renders High Expression and Solubility. Protein J 2017; 36:7-16. [PMID: 28120227 DOI: 10.1007/s10930-017-9693-2] [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] [Indexed: 01/07/2023]
Abstract
Gamma glutamyl transpeptidase, (GGT) is a ubiquitous protein which plays a central role in glutathione metabolism and has myriad clinical implications. It has been shown to be a virulence factor for pathogenic bacteria, inhibition of which results in reduced colonization potential. However, existing inhibitors are effective but toxic and therefore search is on for novel inhibitors, which makes it imperative to understand the interactions of various inhibitors with the protein in substantial detail. High resolution structures of protein bound to different inhibitors can serve this purpose. Gamma glutamyl transpeptidase from Bacillus licheniformis is one of the model systems that have been used to understand the structure-function correlation of the protein. The structures of the native protein (PDB code 4OTT), of its complex with glutamate (PDB code 4OTU) and that of its precursor mimic (PDB code 4Y23) are available, although at moderate/low resolution. In the present study, we are reporting the preliminary analysis of, high resolution X-ray diffraction data collected for the co-crystals of B. licheniformis, Gamma glutamyl transpeptidase, with its inhibitor, Acivicin. Crystals belong to the orthorhombic space group P212121 and diffract X-ray to 1.45 Å resolution. This is the highest resolution data reported for all GGT structures available till now. The use of SUMO fused expression system enhanced yield of the target protein in the soluble fraction, facilitating recovery of protein with high purity. The preliminary analysis of this data set shows clear density for the inhibitor, acivicin, in the protein active site.
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Affiliation(s)
- Shobha Kumari
- Department of Biophysics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Ravi Kant Pal
- National Institute of Immunology (NII), Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Rani Gupta
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Manisha Goel
- Department of Biophysics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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Bolz C, Bach NC, Meyer H, Müller G, Dawidowski M, Popowicz G, Sieber SA, Skerra A, Gerhard M. Comparison of enzymatic properties and small molecule inhibition of γ-glutamyltranspeptidases from pathogenic and commensal bacteria. Biol Chem 2017; 398:341-357. [PMID: 27636829 DOI: 10.1515/hsz-2016-0198] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/24/2016] [Indexed: 01/06/2023]
Abstract
Helicobacter pylori infects the stomach of 50% of the population worldwide, thus causing chronic gastritis. Although this infection can be cured by antibiotic treatment, therapeutic options are increasingly limited due to the development of resistances. The γ-glutamyl-transpeptidase (gGT) of H. pylori (HpgGT) is a virulence factor important for colonization and contributes to bacterial immune evasion. Therefore, this enzyme is a potential target for developing new anti-infectives. As species specificity of such compounds is required in order to avoid off-target or adverse effects, comparative analysis of the gGTs from different organisms is a prerequisite for drug development. To allow detailed biochemical and enzymatic characterization, recombinant gGTs from five different bacteria as well as Homo sapiens were characterized and compared. Investigation of the enzymatic activity, the binding modes of known inhibitors to the catalytic center, and a high resolution X-ray structure of the HpgGT provided a starting point for the identification of new inhibitory substances targeting HpgGT. Inhibitors with Ki values in the nm to mm range were identified and their binding modes were analyzed by mass spectrometry. The results of this study provide a basis for the development of species-specific lead compounds with anti-infective potential by effectively inhibiting HpgGT.
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Site-directed mutagenesis of a conserved Asn450 residue of Bacillus licheniformis γ-glutamyltranspeptidase. Int J Biol Macromol 2016; 91:416-25. [DOI: 10.1016/j.ijbiomac.2016.05.101] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 05/27/2016] [Accepted: 05/28/2016] [Indexed: 12/29/2022]
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