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Zhang T, Yao C, Zhou X, Liu S, Qi L, Zhu S, Zhao C, Hu D, Shen W. Glutathione‑degrading enzymes in the complex landscape of tumors (Review). Int J Oncol 2024; 65:72. [PMID: 38847236 PMCID: PMC11173371 DOI: 10.3892/ijo.2024.5660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/24/2024] [Indexed: 06/12/2024] Open
Abstract
Glutathione (GSH)‑degrading enzymes are essential for starting the first stages of GSH degradation. These enzymes include extracellular γ‑glutamyl transpeptidase (GGT) and intracellular GSH‑specific γ‑glutamylcyclotransferase 1 (ChaC1) and 2. These enzymes are essential for cellular activities, such as immune response, differentiation, proliferation, homeostasis regulation and programmed cell death. Tumor tissue frequently exhibits abnormal expression of GSH‑degrading enzymes, which has a key impact on the development and spread of malignancies. The present review summarizes gene and protein structure, catalytic activity and regulation of GSH‑degrading enzymes, their vital roles in tumor development (including regulation of oxidative and endoplasmic reticulum stress, control of programmed cell death, promotion of inflammation and tumorigenesis and modulation of drug resistance in tumor cells) and potential role as diagnostic biomarkers and therapeutic targets.
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Affiliation(s)
- Tianyi Zhang
- Department of Acupuncture, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Chongjie Yao
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
- Department of Rehabilitation, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Xu Zhou
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Shimin Liu
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
- Shanghai Research Institute of Acupuncture and Meridian, Shanghai 200030, P.R. China
| | - Li Qi
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Shiguo Zhu
- School of Basic Medical Sciences, Center for Traditional Chinese Medicine and Immunology Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Chen Zhao
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Dan Hu
- School of Acupuncture-moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Weidong Shen
- Department of Acupuncture, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
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2
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Nishikawa A, Senba H, Kimura Y, Yokota S, Doi M, Takenaka S. Isolation and characterization of a salt-tolerant γ-glutamyl transpeptidase from xerophilic Aspergillus sydowii. 3 Biotech 2022; 12:253. [PMID: 36060894 PMCID: PMC9433638 DOI: 10.1007/s13205-022-03259-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/08/2022] [Indexed: 11/01/2022] Open
Abstract
Xerophilic Aspergillus molds isolated from halo-alkaliphilic and dry environments are attractive genetic resources for obtaining salt- and osmo-adaptive enzymes. A. sydowii MA0196 secreted the largest amount of γ-glutamyl transpeptidase (GGT) during solid-state fermentation at a low initial water activity (a w = 0.85). Gel filtration analysis revealed that the molecular mass of the purified native enzyme (MA0196 GGT) was 120 kDa. SDS-PAGE analysis showed that MA0196 GGT consists of two subunits with molecular masses of 56.4 and 33 kDa, indicating production from a proenzyme via autoproteolysis. Deglycosylation of the subunits by N-glycosidase F yielded 40.9 and 19.6 kDa species. MA0196 GGT retained transpeptidase and hydrolysis activities and their catalytic efficiency (k cat/K m) under high salt and low water activity. The enzyme displayed broad substrate specificity toward γ-glutamyl acceptors such as amino acids and the imidazole dipeptides, carnosine and anserine. Carnosine and L-glutamine were converted into γ-glutamyl-β-alanyl-L-histidine by MA0196 GGT with a 32.9% yield in the presence of 2% (v/v) dimethyl sulfoxide. Phylogenetic analysis indicated that MA0196 GGT forms a distinct lineage from A. oryzae and A. sojae GGTs. These excellent properties indicate that MA0196 GGT can be used in salted fermentation and for producing bioactive peptides. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-022-03259-3.
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Affiliation(s)
- Arisa Nishikawa
- Division of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501 Japan
| | - Hironori Senba
- Division of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501 Japan
- Gen Res Lab, Ozeki Corp, 4-9 Imazu, Nishinomiya, Hyogo 663-8227 Japan
| | - Yukihiro Kimura
- Division of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501 Japan
| | - Satoko Yokota
- Marutomo Co., Ltd, 1696 Kominato, Iyo, Ehime 799-3192 Japan
| | - Mikiharu Doi
- Marutomo Co., Ltd, 1696 Kominato, Iyo, Ehime 799-3192 Japan
| | - Shinji Takenaka
- Division of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501 Japan
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3
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Fabrication of chitosan-coated magnetite nanobiocatalyst with Bacillus atrophaeus γ-glutamyl transpeptidase and its application to the synthesis of a bioactive peptide SCV-07. Process Biochem 2022. [DOI: 10.1016/j.procbio.2022.08.034] [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: 11/18/2022]
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4
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Xie Z, Kawasaki T, Zhou H, Okuzaki D, Okada N, Tachibana M. Targeting GGT1 Eliminates the Tumor-Promoting Effect and Enhanced Immunosuppressive Function of Myeloid-Derived Suppressor Cells Caused by G-CSF. Front Pharmacol 2022; 13:873792. [PMID: 35548341 PMCID: PMC9081766 DOI: 10.3389/fphar.2022.873792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 04/07/2022] [Indexed: 12/25/2022] Open
Abstract
Myeloid-derived suppressor cells (MDSCs) are major immunosuppressive cells that accumulate in tumor-bearing hosts. Since MDSCs suppress anti-tumor immunity and promote tumor progression, they are promising targets for cancer immunotherapy. Granulocyte colony-stimulating factor (G-CSF) is an agent used for the treatment of chemotherapy-induced febrile neutropenia (FN) in patients with cancer. However, several reports have revealed that G-CSF plays crucial immune-related adverse roles in tumor progression through MDSCs. In this study, we showed that MDSCs differentiated in the presence of G-CSF in vitro exhibited enhanced proliferation and immunosuppressive activity compared to those differentiated without G-CSF. RNA sequencing analysis demonstrated that G-CSF enhanced the immunosuppressive function of MDSCs by upregulating gamma-glutamyltransferase (GGT) 1. Moreover, in the EL4 lymphoma-bearing neutropenic mouse model, administration of recombinant G-CSF increased the number of MDSCs and attenuated the anti-cancer effect of chemotherapy. We showed that the combination of GGsTop, a GGT inhibitor, could prevent G-CSF-induced tumor growth, without affecting the promotion of myelopoiesis by G-CSF. These results suggest that targeting GGT1 can mitigate G-CSF-induced enhanced immunosuppressive functions of MDSCs and can eliminate the tumor-promoting effect of G-CSF. Furthermore, GGsTop could be an attractive combination agent during G-CSF treatment for FN in patients with cancer.
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Affiliation(s)
- Zhiqi Xie
- Project for Vaccine and Immune Regulation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Takahiro Kawasaki
- Project for Vaccine and Immune Regulation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Haoyang Zhou
- Project for Vaccine and Immune Regulation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Daisuke Okuzaki
- Single Cell Genomics, Human Immunology, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan.,Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Naoki Okada
- Project for Vaccine and Immune Regulation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Masashi Tachibana
- Project for Vaccine and Immune Regulation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan.,Global Center for Medical Engineering and Informatics, Osaka University, Osaka, Japan
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5
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Lu Y, Luo Y, Zhou J, Hu T, Tu L, Tong Y, Su P, Liu Y, Wang J, Jiang Z, Wu X, Chen X, Huang L, Gao W. Probing the functions of friedelane-type triterpene cyclases from four celastrol-producing plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:555-567. [PMID: 34750899 DOI: 10.1111/tpj.15575] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 10/15/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
Triterpenes are among the most diverse plant natural products, and their diversity is closely related to various triterpene skeletons catalyzed by different 2,3-oxidosqualene cyclases (OSCs). Celastrol, a friedelane-type triterpene with significant bioactivities, is specifically distributed in higher plants, such as Celastraceae species. Friedelin is an important precursor for the biosynthesis of celastrol, and it is synthesized through the cyclization of 2,3-oxidosqualene, with the highest number of rearrangements being catalyzed by friedelane-type triterpene cyclases. However, the molecular mechanisms underlying the catalysis of friedelin production by friedelane-type triterpene cyclases have not yet been fully elucidated. In this study, transcriptome data of four celastrol-producing plants from Celastraceae were used to identify a total of 21 putative OSCs. Through functional characterization, the friedelane-type triterpene cyclases were separately verified in the four plants. Analysis of the selection pressure showed that purifying selection acted on these OSCs, and the friedelane-type triterpene cyclases may undergo weaker selective restriction during evolution. Molecular docking and site-directed mutagenesis revealed that changes in some amino acids that are unique to friedelane-type triterpene cyclases may lead to variations in catalytic specificity or efficiency, thereby affecting the synthesis of friedelin. Our research explored the functional diversity of triterpene synthases from a multispecies perspective. It also provides some references for further research on the relative mechanisms of friedelin biosynthesis.
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Affiliation(s)
- Yun Lu
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
- Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Yunfeng Luo
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Jiawei Zhou
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Tianyuan Hu
- College of Pharmacy, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Lichan Tu
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Yuru Tong
- School of Pharmaceutical Sciences, Capital Medical University, Beijing, China
| | - Ping Su
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, USA
| | - Yuan Liu
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Jiadian Wang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Zhouqian Jiang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Xiaoyi Wu
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Xiaochao Chen
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Luqi Huang
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Wei Gao
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, China
- Beijing Shijitan Hospital, Capital Medical University, Beijing, China
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6
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7
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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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8
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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: 28] [Impact Index Per Article: 9.3] [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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9
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Vitale D, Picó Y, Spanò N, Torreblanca A, Del Ramo J. Carbamazepine exposure in the sea anemones Anemonia sulcata and Actinia equina: Metabolite identification and physiological responses. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 744:140891. [PMID: 32711318 DOI: 10.1016/j.scitotenv.2020.140891] [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: 04/01/2020] [Revised: 06/17/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
Pharmaceuticals and other emerging contaminants (EC) have been increasingly detected and measured in coastal waters and large effort has been devoted to knowing the effects these substances have in coastal ecosystems. Anthozoa class is underrepresented in ecotoxicology studies despite some of their species being endangered. Anemonia sulcata and Actinia equina are species widely distributed in the Mediterranean Sea. The objectives of this work have been to evaluate the ability of these species to accumulate carbamazepine (CBZ) from water, to determine the effects of this pharmaceutical on some physiological and biochemical endpoints and to characterize the degradation routes followed by this compound in Anthozoa tissues (biotransformation) and water. Sea anemones were exposed to 1 μg L-1 and 100 μg L-1 of CBZ in artificial sea water in a semi-static system for 8 days. At several times small portions of the tentacles and whole organisms were taken. Ion transport (measured as NKATPase activity), energetic metabolism (measured as glucose and lactate levels) and nitrogen excretion (measured as ammonia concentration in tissues) were determined. CBZ-exposed individuals of A. sulcata and A. equina were analyzed by ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS) on a quadrupole-time-of-flight (QqTOF). The structures of nine metabolites have been tentatively identified using HRMS and HRMS/MS data with the aid of the free available Medline database. The current work constitutes the first study on the identification of Cnidarian metabolites of CBZ in species of the Anthozoa class.
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Affiliation(s)
- Dyana Vitale
- Food and Environmental Safety Research Group (SAMA-UV), Desertification Research Centre (CIDE, UV-CSIC-GV), University of Valencia, Spain
| | - Yolanda Picó
- Food and Environmental Safety Research Group (SAMA-UV), Desertification Research Centre (CIDE, UV-CSIC-GV), University of Valencia, Spain
| | - Nunziacarla Spanò
- Department of Dental Biomedical Sciences and Morphological and Functional Images, University of Messina, Italy
| | - Amparo Torreblanca
- Departament of Cell Biology, Functional Biology and Physical Anthropology, University of Valencia, Spain.
| | - Jose Del Ramo
- Departament of Cell Biology, Functional Biology and Physical Anthropology, University of Valencia, Spain
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10
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Oliva F, Flores-Canales JC, Pieraccini S, Morelli CF, Sironi M, Schiøtt B. Simulating Multiple Substrate-Binding Events by γ-Glutamyltransferase Using Accelerated Molecular Dynamics. J Phys Chem B 2020; 124:10104-10116. [PMID: 33112625 DOI: 10.1021/acs.jpcb.0c06907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
γ-Glutamyltransferase (GGT) is an enzyme that uses γ-glutamyl compounds as substrates and catalyzes their transfer to a water molecule or an acceptor substrate with varied physiological function in bacteria, plants, and animals. Crystal structures of GGT are known for different species and in different states of the chemical reaction; however, the structural dynamics of the substrate binding to the catalytic site of GGT are unknown. Here, we modeled Escherichia coli GGT's glutamine binding by using a swarm of accelerated molecular dynamics (aMD) simulations. Characterization of multiple binding events identified three structural binding motifs composed of polar residues in the binding pocket that govern glutamine binding into the active site. Simulated open and closed conformations of a lid-loop protecting the binding cavity suggest its role as a gating element by allowing or blocking substrates entry into the binding pocket. Partially open states of the lid-loop are accessible within thermal fluctuations, while the estimated free energy cost of a complete open state is 2.4 kcal/mol. Our results suggest that both specific electrostatic interactions and GGT conformational dynamics dictate the molecular recognition of substrate-GGT complexes.
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Affiliation(s)
- Francesco Oliva
- Dipartimento di Chimica, Università degli studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Jose C Flores-Canales
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Stefano Pieraccini
- Dipartimento di Chimica, Università degli studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Carlo F Morelli
- Dipartimento di Chimica, Università degli studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Maurizio Sironi
- Dipartimento di Chimica, Università degli studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Birgit Schiøtt
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
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11
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An R, Wei S, Huang Z, Liu F, Ye D. An Activatable Chemiluminescent Probe for Sensitive Detection of γ-Glutamyl Transpeptidase Activity in Vivo. Anal Chem 2019; 91:13639-13646. [PMID: 31560193 DOI: 10.1021/acs.analchem.9b02839] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Activatable chemiluminescent probes that show enhanced chemiluminescence upon interaction with a molecular target of interest have offered promising tools for sensing and bioimaging in terms of low background, high sensitivity, and improved penetration depth in biological tissues. Here, we reported a γ-glutamyl transpeptidase (GGT) activatable chemiluminescent probe for real-time detection of GGT activity in vitro and in living mice. The probe was designed by caging an electron-withdrawing acrylic group-substituted Schaap's phenoxy-dioxetane with a GGT-recognitive substrate (γ-Glu) and a self-immolative linker (p-aminobenzyl alcohol), which was initially chemiluminescence off. Upon interaction with GGT, strong chemiluminescence with a more than 800-fold turn-on ratio could be achieved in aqueous solution, allowing to specifically detect GGT activity with ultrahigh signal-to-background ratio and sensitivity in vitro and in live cells. We demonstrated that the probe was reliable to quantify the GGT in serum, permitting to accurately report the elevated levels of GGT in lipopolysaccharide-treated mouse serum. Moreover, through real-time chemiluminescence imaging of GGT activity, the designed probe was feasible to detect GGT-positive tumors in living mice after intravenous systemic administration. This study demonstrates the high potential of GGT-activatable chemiluminescent probe for serum assays and molecular imaging, which might find wide applications in diagnosis of GGT-related diseases.
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Affiliation(s)
- Ruibing An
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Shixuan Wei
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Zheng Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Fei Liu
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Deju Ye
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
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12
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Sun J, Chang M, Li H, Zhang Z, Chen Q, Chen Y, Yao Y, Pan A, Shi C, Wang C, Zhao J, Wan X. Endophytic Bacteria as Contributors to Theanine Production in Camellia sinensis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:10685-10693. [PMID: 31479251 DOI: 10.1021/acs.jafc.9b03946] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Theanine is the most abundant non-protein amino acid in Camellia sinensis, but it is not known how a tea plant accumulates such high levels of theanine. The endophyte isolated from in vitro grown plantlets of C. sinensis cultivars was identified as Luteibacter spp., showing strong biocatalytic activity for converting both glutamine and ethylamine to theanine. Theanine was secreted outside of the bacteria. The endophyte isolated from in vitro plantlets of Camellia oleifera cultivar was identified as Bacillus safensis and did not convert glutamine and ethylamine to theanine. Enzymatic assays in vitro indicated that γ-glutamyltranspeptidases rCsEGGTs from the endophyte Luteibacter strains converted glutamine and ethylamine to theanine at higher rates than rCsGGTs from C. sinensis. This is the first report on theanine biosynthesis by an endophyte from C. sinensis, which provides a new pathway to explore the mechanism of theanine biosynthesis in C. sinensis and the interactions between an endophyte and tea plants.
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13
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Elhosseiny NM, Elhezawy NB, Attia AS. Comparative proteomics analyses of Acinetobacter baumannii strains ATCC 17978 and AB5075 reveal the differential role of type II secretion system secretomes in lung colonization and ciprofloxacin resistance. Microb Pathog 2019; 128:20-27. [DOI: 10.1016/j.micpath.2018.12.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/16/2018] [Accepted: 12/19/2018] [Indexed: 12/20/2022]
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14
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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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15
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Tian L, Chou HL, Zhang L, Hwang SK, Starkenburg SR, Doroshenk KA, Kumamaru T, Okita TW. RNA-Binding Protein RBP-P Is Required for Glutelin and Prolamine mRNA Localization in Rice Endosperm Cells. THE PLANT CELL 2018; 30:2529-2552. [PMID: 30190374 PMCID: PMC6241268 DOI: 10.1105/tpc.18.00321] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 08/08/2018] [Accepted: 08/31/2018] [Indexed: 05/18/2023]
Abstract
In developing rice (Oryza sativa) endosperm, mRNAs of the major storage proteins, glutelin and prolamine, are transported and anchored to distinct subdomains of the cortical endoplasmic reticulum. RNA binding protein RBP-P binds to both glutelin and prolamine mRNAs, suggesting a role in some aspect of their RNA metabolism. Here, we show that rice lines expressing mutant RBP-P mislocalize both glutelin and prolamine mRNAs. Different mutant RBP-P proteins exhibited varying degrees of reduced RNA binding and/or protein-protein interaction properties, which may account for the mislocalization of storage protein RNAs. In addition, partial loss of RBP-P function conferred a broad phenotypic variation ranging from dwarfism, chlorophyll deficiency, and sterility to late flowering and low spikelet fertility. Transcriptome analysis highlighted the essential role of RBP-P in regulating storage protein genes and several essential biological processes during grain development. Overall, our data demonstrate the significant roles of RBP-P in glutelin and prolamine mRNA localization and in the regulation of genes important for plant growth and development through its RNA binding activity and cooperative regulation with interacting proteins.
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Affiliation(s)
- Li Tian
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | - Hong-Li Chou
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Laining Zhang
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | - Seon-Kap Hwang
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | | | - Kelly A Doroshenk
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | | | - Thomas W Okita
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
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16
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Luo Z, An R, Ye D. Recent Advances in the Development of Optical Imaging Probes for γ-Glutamyltranspeptidase. Chembiochem 2018; 20:474-487. [PMID: 30062708 DOI: 10.1002/cbic.201800370] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Indexed: 12/11/2022]
Abstract
γ-Glutamyltranspeptidase (GGT) is a cell-membrane-bound protease that participates in cellular glutathione and cysteine homeostasis, which are closely related to many physiological and pathological processes. The accurate measurement of GGT activity is useful for the early diagnosis of diseases. In the past few years, many efforts have been made to build optical imaging probes for the detection of GGT activity both in vitro and in vivo. In this Minireview, recent advances in the development of various optical imaging probes for GGT, including activatable fluorescence probes, ratiometric fluorescence probes, and activatable bioluminescence probes, are summarized. This review starts from the instruction of the GGT enzyme and its biological functions, followed by a discussion of activatable fluorescence probes that show off-on fluorescence in response to GGT. GGT-activatable two-photon fluorescence imaging probes with improved imaging depth and spatial resolution are also discussed. Ratiometric fluorescence probes capable of accurately reporting on GGT levels through a self-calibration mechanism are discussed, followed by describing GGT-activatable bioluminescence probes that can offer a high signal-to-background ratio to detect GGT in living mice. Finally, current challenges and further perspectives for the development of molecular imaging probes for GGT are addressed.
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Affiliation(s)
- Zhiliang Luo
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P.R. China
| | - Ruibing An
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P.R. China
| | - Deju Ye
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P.R. China
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17
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Zhang L, Veith PD, Huq NL, Chen YY, Seers CA, Cross KJ, Gorasia DG, Reynolds EC. Porphyromonas gingivalis Gingipains Display Transpeptidation Activity. J Proteome Res 2018; 17:2803-2818. [PMID: 29984580 DOI: 10.1021/acs.jproteome.8b00286] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Porphyromonas gingivalis is a keystone periodontal pathogen that has been associated with autoimmune disorders. The cell surface proteases Lys-gingipain (Kgp) and Arg-gingipains (RgpA and RgpB) are major virulence factors, and their proteolytic activity is enhanced by small peptides such as glycylglycine (GlyGly). The reaction kinetics suggested that GlyGly may function as an acceptor molecule for gingipain-catalyzed transpeptidation. Purified gingipains and P. gingivalis whole cells were used to digest selected substrates including human hemoglobin in the presence or absence of peptide acceptors. Mass spectrometric analysis of the substrates digested with gingipains in the presence of GlyGly showed that transpeptidation outcompeted hydrolysis, whereas the trypsin-digested controls exhibited predominantly hydrolysis activity. The transpeptidation levels increased with increasing concentration of GlyGly. Purified gingipains and whole cells exhibited extensive transpeptidation activities on human hemoglobin. All hemoglobin cleavage sites were found to be suitable for GlyGly transpeptidation, and this transpeptidation enhanced hemoglobin digestion. The transpeptidation products were often more abundant than the corresponding hydrolysis products. In the absence of GlyGly, hemoglobin peptides produced during digestion were utilized as acceptors leading to the detection of up to 116 different transpeptidation products in a single reaction. P. gingivalis cells were able to digest hemoglobin faster when acceptor peptides derived from human serum albumin were included in the reaction, suggesting that gingipain-catalyzed transpeptidation may be relevant for substrates encountered in vivo. The transpeptidation of host proteins in vivo may potentially lead to the breakdown of immunological tolerance, culminating in autoimmune reactions.
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Affiliation(s)
- Lianyi Zhang
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Paul D Veith
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - N Laila Huq
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Yu-Yen Chen
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Christine A Seers
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Keith J Cross
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Dhana G Gorasia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
| | - Eric C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute , The University of Melbourne , Melbourne , Victoria , Australia
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18
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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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19
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Sarkar R, Mdladla C, Macingwana L, Pietersen RD, Ngwane A, Tabb D, van Helden P, Wiid I, Baker B. Proteomic analysis reveals that sulfamethoxazole induces oxidative stress in M. tuberculosis. Tuberculosis (Edinb) 2018; 111:78-85. [DOI: 10.1016/j.tube.2018.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/27/2018] [Accepted: 05/15/2018] [Indexed: 02/04/2023]
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20
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Abstract
Many potentially toxic electrophilic xenobiotics and some endogenous compounds are detoxified by conversion to the corresponding glutathione S-conjugate, which is metabolized to the N-acetylcysteine S-conjugate (mercapturate) and excreted. Some mercapturate pathway components, however, are toxic. Bioactivation (toxification) may occur when the glutathione S-conjugate (or mercapturate) is converted to a cysteine S-conjugate that undergoes a β-lyase reaction. If the sulfhydryl-containing fragment produced in this reaction is reactive, toxicity may ensue. Some drugs and halogenated workplace/environmental contaminants are bioactivated by this mechanism. On the other hand, cysteine S-conjugate β-lyases occur in nature as a means of generating some biologically useful sulfhydryl-containing compounds.
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21
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Kaushik V, Verma VV, Goel M. Functional divergence and comparative in-silico study of Cas4 proteins of DUF83 class. J Mol Recognit 2017; 31:e2694. [PMID: 29243852 DOI: 10.1002/jmr.2694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 11/14/2017] [Accepted: 11/14/2017] [Indexed: 11/08/2022]
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated (CRISPR-Cas) systems present in genomes of bacteria and archaea have been the focus of many research studies recently. The Cas4 proteins of these systems are thought to be responsible for the adaptation step in the CRISPR mechanism. Cas4 proteins exhibit low sequence similarity among themselves and are currently classified into 2 main classes: DUF83 and DUF911. The characteristic features of Cas4 proteins belonging to DUF83 class have been elucidated by determining the structures of Cas4 protein from Sulfolobus solfataricus and Pyrobaculum calidifontis. Although, both Cas4 proteins characterized structurally are of same DUF83 class, these 2 proteins do exhibit significant biochemical and functional differences. The aim of the present study was to explore the structural and evolutionary features responsible for these differences. Our study predicts residues which might be responsible for such differences. Functional divergence analysis was used to predict sites exhibiting type I divergence, where certain amino acids are conserved in 1 clade whereas the same site is highly variable in the other clade. Our intra-molecular interaction analysis reinforces the influence of such divergence sites on the other functionally important amino acids. In general, this study identifies some of the divergence hotspots that could be the focus of future experimental studies for better understanding of Cas4 enzymatic activity in CRISPR mechanism.
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Affiliation(s)
- Vineeta Kaushik
- Department of Biophysics, University of Delhi, New Delhi, India
| | - Ved Vrat Verma
- Department of Biophysics, University of Delhi, New Delhi, India
| | - Manisha Goel
- Department of Biophysics, University of Delhi, New Delhi, India
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22
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Abstract
SIGNIFICANCE Glutathione degradation has for long been thought to occur only on noncytosolic pools. This is because there has been only one enzyme known to degrade glutathione (γ-glutamyl transpeptidase) and this localizes to either the plasma membrane (mammals, bacteria) or the vacuolar membrane (yeast, plants) and acts on extracellular or vacuolar pools. The last few years have seen the discovery of several new enzymes of glutathione degradation that function in the cytosol, throwing new light on glutathione degradation. Recent Advances: The new enzymes that have been identified in the last few years that can initiate glutathione degradation include the Dug enzyme found in yeast and fungi, the ChaC1 enzyme found among higher eukaryotes, the ChaC2 enzyme found from bacteria to man, and the RipAY enzyme found in some bacteria. These enzymes play roles ranging from housekeeping functions to stress responses and are involved in processes such as embryonic neural development and pathogenesis. CRITICAL ISSUES In addition to delineating the pathways of glutathione degradation in detail, a critical issue is to find how these new enzymes impact cellular physiology and homeostasis. FUTURE DIRECTIONS Glutathione degradation plays a far greater role in cellular physiology than previously envisaged. The differential regulation and differential specificities of various enzymes, each acting on distinct pools, can lead to different consequences to the cell. It is likely that the coming years will see these downstream effects being unraveled in greater detail and will lead to a better understanding and appreciation of glutathione degradation. Antioxid. Redox Signal. 27, 1200-1216.
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Affiliation(s)
- Anand Kumar Bachhawat
- Department of Biological Sciences, Indian Institute of Science Education and Research , Mohali, Mohali, India
| | - Amandeep Kaur
- Department of Biological Sciences, Indian Institute of Science Education and Research , Mohali, Mohali, India
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23
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Sharma E, Joshi R, Gulati A. l-Theanine: An astounding sui generis integrant in tea. Food Chem 2017; 242:601-610. [PMID: 29037735 DOI: 10.1016/j.foodchem.2017.09.046] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 09/06/2017] [Accepted: 09/11/2017] [Indexed: 11/30/2022]
Abstract
l-theanine (l-Th), a non-protein amino acid present in tea, is a valuable nutraceutical product with unique health benefits and used as an additive in food industry. l-Th enhances the umami taste but its use is limited due to its inadequate production. Different extraction approaches from tea shoots, chemical synthesis to microbial transformation have been tried to meet its demand. In vitro, in vivo as well as clinical studies have shown its positive effect in regulating CNS disorders. l-Th has become choice ingredient in CNS active products due to its anti-stress and neuroprotective role in dementias particularly in retrogression of Alzheimer's. l-Th biochemically modulates various anti-neoplastic agents by increasing their bioavailability in tumour cells. The review, is an effort to condense the recent research on l-Th highlighting its biological resource, plausible role in tea plant, production approaches, its physiological role on human health and future prospects.
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Affiliation(s)
- Eshita Sharma
- CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India; Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Robin Joshi
- CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India
| | - Ashu Gulati
- CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India.
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24
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Babonis LS, Martindale MQ. PaxA, but not PaxC, is required for cnidocyte development in the sea anemone Nematostella vectensis. EvoDevo 2017; 8:14. [PMID: 28878874 PMCID: PMC5584322 DOI: 10.1186/s13227-017-0077-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/16/2017] [Indexed: 12/25/2022] Open
Abstract
Background Pax genes are a family of conserved transcription factors that regulate many aspects of developmental morphogenesis, notably the development of ectodermal sensory structures including eyes. Nematostella vectensis, the starlet sea anemone, has numerous Pax orthologs, many of which are expressed early during embryogenesis. The function of Pax genes in this eyeless cnidarian is unknown. Results Here, we show that PaxA, but not PaxC, plays a critical role in the development of cnidocytes in N. vectensis. Knockdown of PaxA results in a loss of developing cnidocytes and downregulation of numerous cnidocyte-specific genes, including a variant of the transcription factor Mef2. We also demonstrate that the co-expression of Mef2 in a subset of the PaxA-expressing cells is associated with the development with a second lineage of cnidocytes and show that knockdown of the neural progenitor gene SoxB2 results in downregulation of expression of PaxA, Mef2, and several cnidocyte-specific genes. Because PaxA is not co-expressed with SoxB2 at any time during cnidocyte development, we propose a simple model for cnidogenesis whereby a SoxB2-expressing progenitor cell population undergoes division to give rise to PaxA-expressing cnidocytes, some of which also express Mef2. Discussion The role of PaxA in cnidocyte development among hydrozoans has not been studied, but the conserved role of SoxB2 in regulating the fate of a progenitor cell that gives rise to neurons and cnidocytes in Nematostella and Hydractinia echinata suggests that this SoxB2/PaxA pathway may well be conserved across cnidarians.
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Affiliation(s)
- Leslie S Babonis
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St. Augustine, FL 32080 USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St. Augustine, FL 32080 USA.,Department of Biology, University of Florida, Gainesville, FL 32611 USA
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25
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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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26
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Abstract
A comparison of whole-fish polychlorinated biphenyl (PCB) and total mercury (Hg) concentrations in mature males with those in mature females may provide insights into sex differences in behavior, metabolism, and other physiological processes. In eight species of fish, we observed that males exceeded females in whole-fish PCB concentration by 17 to 43 %. Based on results from hypothesis testing, we concluded that these sex differences were most likely primarily driven by a higher rate of energy expenditure, stemming from higher resting metabolic rate (or standard metabolic rate (SMR)) and higher swimming activity, in males compared with females. A higher rate of energy expenditure led to a higher rate of food consumption, which, in turn, resulted in a higher rate of PCB accumulation. For two fish species, the growth dilution effect also made a substantial contribution to the sex difference in PCB concentrations, although the higher energy expenditure rate for males was still the primary driver. Hg concentration data were available for five of the eight species. For four of these five species, the ratio of PCB concentration in males to PCB concentration in females was substantially greater than the ratio of Hg concentration in males to Hg concentration in females. In sea lamprey (Petromyzon marinus), a very primitive fish, the two ratios were nearly identical. The most plausible explanation for this pattern was that certain androgens, such as testosterone and 11-ketotestosterone, enhanced Hg-elimination rate in males. In contrast, long-term elimination of PCBs is negligible for both sexes. According to this explanation, males not only ingest Hg at a higher rate than females but also eliminate Hg at a higher rate than females, in fish species other than sea lamprey. Male sea lamprey do not possess either of the above-specified androgens. These apparent sex differences in SMRs, activities, and Hg-elimination rates in teleost fishes may also apply, to some degree, to higher vertebrates including humans. Our synthesis findings will be useful in (1) developing sex-specific bioenergetics models for fish, (2) developing sex-specific risk assessment models for exposure of humans and wildlife to contaminants, and (3) refining Hg mass balance models for fish and higher vertebrates.
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