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Chen TY, Shyur E, Ma TH, Wijeyewickrema L, Lin SW, Kao MR, Liang PH, Shie JJ, Chuang EY, Liou JP, Hsieh YSY. Effect of Sulfotyrosine and Negatively Charged Amino Acid of Leech-Derived Peptides on Binding and Inhibitory Activity Against Thrombin. Chembiochem 2024; 25:e202300744. [PMID: 38055188 DOI: 10.1002/cbic.202300744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 12/07/2023]
Abstract
Hirudins, natural sulfo(glyco)proteins, are clinical anticoagulants that directly inhibit thrombin, a key coagulation factor. Their potent thrombin inhibition primarily results from antagonistic interactions with both the catalytic and non-catalytic sites of thrombin. Hirudins often feature sulfate moieties on Tyr residues in their anionic C-terminus region, enabling strong interactions with thrombin exosite-I and effectively blocking its engagement with fibrinogen. Although sulfotyrosines have been identified in various hirudin variants, the precise relationship between sulfotyrosine and the number of negatively charged amino acids within the anionic-rich C-terminus peptide domain for the binding of thrombin has remained elusive. By using Fmoc-SPPS, hirudin dodecapeptides homologous to the C-terminus of hirudin variants from various leech species were successfully synthesized, and the effect of sulfotyrosine and the number of negatively charged amino acids on hirudin-thrombin interactions was investigated. Our findings did not reveal any synergistic effect between an increasing number of sulfotyrosines or negatively charged amino acids and their inhibitory activity on thrombin or fibrinolysis in the assays, despite a higher binding level toward thrombin in the sulfated dodecapeptide Hnip_Hirudin was observed in SPR analysis.
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Affiliation(s)
- Tzu-Yin Chen
- School of Pharmacy, College of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 11031, Taiwan
| | - Eileen Shyur
- School of Pharmacy, College of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 11031, Taiwan
| | - Tzu-Hsuan Ma
- School of Pharmacy, College of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 11031, Taiwan
| | - Lakshmi Wijeyewickrema
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, 3086, Melbourne, Australia
| | - Sheng-Wei Lin
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei, 115, Taiwan
| | - Mu-Rong Kao
- School of Pharmacy, College of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 11031, Taiwan
| | - Pi-Hui Liang
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Jiun-Jie Shie
- Institute of Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei, 115, Taiwan
| | - Er-Yuan Chuang
- Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, 250 Wuxing Street, Taipei, 11031, Taiwan
| | - Jing-Ping Liou
- School of Pharmacy, College of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 11031, Taiwan
| | - Yves S Y Hsieh
- School of Pharmacy, College of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 11031, Taiwan
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, SE10691, Sweden
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Sun Y, Wang B, Pei J, Luo Y, Yuan N, Xiao Z, Wu H, Luo C, Wang J, Wei S, Pei Y, Fu S, Wang D. Molecular dynamic and pharmacological studies on protein-engineered hirudin variants of Hirudinaria manillensis and Hirudo medicinalis. Br J Pharmacol 2022; 179:3740-3753. [PMID: 35135035 DOI: 10.1111/bph.15816] [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: 09/23/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Hirudin variants are the most powerful thrombin inhibitors discovered to date, with a lower risk of bleeding than heparin. For anticoagulation, the C-termini of hirudins bind to the exocite I of thrombin. Anticoagulant effects of gene-recombinant hirudin are weaker than natural hirudin for the reason of lacking tyrosine-O-sulfation at C terminus. EXPERIMENTAL APPROACH The integrative pharmacological study applied molecular dynamic, molecular biological, and in vivo and in vitro experiments to elucidate the anticoagulant effects of protein-engineered hirudins. KEY RESULTS Molecular dynamic (MD) analysis showed that modifications of the C-termini of hirudin variant 1 of Hirudo medicinalis (HV1) and hirudin variant 2 of Hirudinaria manillensis (HM2) changed the binding energy of the C-termini to human thrombin. The study indicated Asp61 of HM2 that corresponds to sulfated Tyr63 of HV1 is critical for inhibiting thrombin activities, and the anticoagulant effects of HV1 and HM2 were improved when the amino acid residues adjacent to Asp61 were mutated to Asp, such as the prolongation of the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) of human blood, and decreased Ki and IC50 values. In the in vivo experiments, mutations at C-termini of HV1 and HM2 significantly changed APTT, PT and TT. CONCLUSION AND IMPLICATIONS The study indicated that the anticoagulant effects of gene-engineered HM2 are stronger than gene-engineered HV1, and HM2-E60D-I62D has the strongest effects and could be an antithrombotic medicine with better therapeutic effects.
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Affiliation(s)
- Yan Sun
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Baochun Wang
- The First Department of Gastrointestinal Surgery, Hainan General Hospital, Haikou, Hainan, China
| | - Jinli Pei
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China.,Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Ying Luo
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Nan Yuan
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Zhengpan Xiao
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Hao Wu
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China.,Central Laboratory, Ningbo Medical Center Lihuili Hospital, Ningbo, Zhejiang, China
| | - Chenghui Luo
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Jiaxuan Wang
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Shuangshuang Wei
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Yechun Pei
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Shengmiao Fu
- Department of Medical Laboratory Science, Hainan General Hospital, Haikou, Hainan, China
| | - Dayong Wang
- Laboratory of Biopharmaceutics and Molecular Pharmacology, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China.,Key laboratory of Tropical Biological Resources of the Ministry of Education of China, Hainan University, Haikou, Hainan, China
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3
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Dong X, Meng Z, Jin J, Gu R, Dou G. Development, validation, and clinical pharmacokinetic application of ultra-performance liquid chromatography/tandem mass spectrometry method for simultaneously determining a novel recombinant hirudin derivative (Neorudin) and its active metabolite in human serum. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1063:204-213. [PMID: 28886579 DOI: 10.1016/j.jchromb.2017.08.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 07/16/2017] [Accepted: 08/20/2017] [Indexed: 11/16/2022]
Abstract
Recombinant Neorudin (EPR-hirudin, EH), a novel, low-bleeding anticoagulant fusion protein, has been developed as an inactive prodrug that is converted to an active metabolite, hirudin variant 2-Lys47 (HV2), at the thrombus site and is undergoing Phase I clinical trials in China. The goal of our present research was to establish a novel ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method for simultaneously quantifying EH and HV2 in human serum. Furthermore, the method was used in clinical pharmacokinetic study after validation. The stock and dilute working solutions were dissolved in methanol/water (1/1, v/v) to avoid their adsorption. The internal standard (IS) used, had a similar structure to that of EH. The serum sample pretreatment involved protein precipitation with methanol. The volume ratio of the precipitating solvent to the serum sample was 3:1 (300μL methanol: 100μL serum sample). The chromatographic separation was performed using a 300Å C18 column using a multi-step gradient with a mobile phase consisting of acetonitrile:water containing 0.1% formic acid. The detection was carried out using an ESI source in the positive multiple reaction monitoring (MRM) mode. The within and between run precision were in the range of 3.5%-10.3% for EH and 3.3%-8.8% for HV2, and the accuracy of both EH and HV2 was between -4.6% and 2.1%. The extraction recoveries and matrix effect at three quality control (QC) levels for EH and HV2 were satisfactory. The stabilities of EH and HV2 during the storage, preparation, and analysis were confirmed, and the carryover also proved to be acceptable. This technique was efficiently used in Phase I clinical pharmacokinetic trials of EH following intravenous administration of 0.2mg/kg to healthy volunteers.
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Affiliation(s)
- Xiaona Dong
- State Key Laboratory of Drug Metabolism and Pharmacokinetics, Laboratory of Hematological Pharmacology, Beijing Institute of Transfusion Medicine, 27, Taiping Road, Haidian District, Beijing 100850, PR China.
| | - Zhiyun Meng
- State Key Laboratory of Drug Metabolism and Pharmacokinetics, Laboratory of Hematological Pharmacology, Beijing Institute of Transfusion Medicine, 27, Taiping Road, Haidian District, Beijing 100850, PR China.
| | - Jide Jin
- Laboratory of Experimental Hematology, Beijing Institute of Radiation Medicine, 27, Taiping Road, Beijing 100850, PR China.
| | - Ruolan Gu
- State Key Laboratory of Drug Metabolism and Pharmacokinetics, Laboratory of Hematological Pharmacology, Beijing Institute of Transfusion Medicine, 27, Taiping Road, Haidian District, Beijing 100850, PR China.
| | - Guifang Dou
- State Key Laboratory of Drug Metabolism and Pharmacokinetics, Laboratory of Hematological Pharmacology, Beijing Institute of Transfusion Medicine, 27, Taiping Road, Haidian District, Beijing 100850, PR China.
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Chen Y, Diener K, Patel IR, Kawooya JK, Martin GA, Yamdagni P, Zhang X, Sandrasalphaa A, Sahasrabudhe S, Busch SJ. Phage Display of Functional Human TNF-α Converting Enzyme Catalytic Domain: A Rapid Method for the Production of Stabilized Proteolytic Proteins for Assay Development and High-Throughput Screening. ACTA ACUST UNITED AC 2016; 7:433-40. [PMID: 14599359 DOI: 10.1177/108705702237675] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The catalytic domain of human tumor necrosis factor-α (TNF-α) converting enzyme (TACE) was expressed in a phage display system to determine whether stable and active enzyme could be made for high-throughput screening (HTS). This would address many issues around screening of proteases in this class. The phage-displayed TACE catalytic domain (PDT) properly cleaved the fusion protein of glutathione S-transferase (GST)-pro-TNF-α to generate the mature TNF-α in vitro. To determine the utility of the PDT in HTS, the authors further demonstrated that PDT was able to generate a strong reproducible fluorescence signal by cleaving a fluorogenic TNF-α-specific peptide in vitro. More important, the catalytic activity of the PDT was inhibited by a broad-spectrum matrix metalloprotease (MMP) inhibitor but not by an MMP-I specific inhibitor, illustrating the potential utility of PDT for HTS. The PDT was also compared with baculovirus-expressed TACE (BET) in these assays to establish the relative efficacy of PDT. Both PDT and BET showed a similar specific cleavage profile against the defined substrates. Activity of the BET, however, was stable at 4 °C for less than 24 h. In contrast, the PDT exhibited remarkable stability, losing very little activity even after 2 years at 4 °C. On the basis of these results, the authors concluded that the phage display system might be a useful tool for expressing proteins that have stability issues related to auto-proteolytic activity. Furthermore, the ease and low cost of large-scale production of phage should make it suitable for assay development and HTS.
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Affiliation(s)
- Yangde Chen
- Department of Functional Genomics, Aventis Pharmaceuticals, Inc., Bridgewater, NJ, USA
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5
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Wirsching F, Keller M, Hildmann C, Riester D, Schwienhorst A. Directed evolution towards protease-resistant hirudin variants. Mol Genet Metab 2003; 80:451-62. [PMID: 14654359 DOI: 10.1016/j.ymgme.2003.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hirudin, a thrombin-specific inhibitor, is efficiently digested and inactivated by proteases with pepsin- and chymotrypsin-like specificity. Using a combination of phage display selection and high-throughput screening methods, several variants of recombinant hirudin were generated. Only very few variants comprising amino acid substitutions in the amino-terminal domain (residues 1-5) and in the carboxyl-terminal tail (residues 49, 50, and/or 56, 57, 62-64) were identified that showed thrombin inhibition activities similar to those of the wild-type polypeptide. Analysis of protease susceptibility, however, revealed that mutations, which conferred protease resistance, simultaneously diminish thrombin inhibition activity. This is particularly apparent for substitutions in the region of residues 56-64, which forms a large number of electrostatic and hydrophobic interactions with thrombin in the crystal structure of the complex. Unlike wild-type hirudin, the variant comprising Pro(50)- ...-His(56)-Asp(57)- ...-Pro(62)-Pro(63)-His(64) is completely resistant to pepsin and chymotrypsin cleavage; however, this is at the expense of thrombin inhibition activity where there is a 100-fold increase in the IC50 value. The frequent replacement of wild-type amino acids by proline at major protease cleavage sites indicates that at least pepsin- and chymotrypsin-like enzymes may exhibit a (conformational) specificity concerning the P1 and P2 positions. On the basis of these results, proline substitutions appear to be a general strategy to design polypeptides that are not susceptible to digestion by a broader range of different proteases.
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Affiliation(s)
- Frank Wirsching
- Abteilung fuer Molekulare Genetik und Praeparative Molekularbiologie, Institut fuer Mikrobiologie und Genetik, Grisebachstr. 8, 37077, Goettingen, Germany
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6
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Lian Q, Szarka SJ, Ng KKS, Wong SL. Engineering of a staphylokinase-based fibrinolytic agent with antithrombotic activity and targeting capability toward thrombin-rich fibrin and plasma clots. J Biol Chem 2003; 278:26677-86. [PMID: 12736246 DOI: 10.1074/jbc.m303241200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Current clinically approved thrombolytic agents have significant drawbacks including reocclusion and bleeding complications. To address these problems, a staphylokinase-based thrombolytic agent equipped with antithrombotic activity from hirudin was engineered. Because the N termini for both staphylokinase and hirudin are required for their activities, a Y-shaped molecule is generated using engineered coiled-coil sequences as the heterodimerization domain. This agent, designated HE-SAKK, was produced and assembled from Bacillus subtilis via secretion using an optimized co-cultivation approach. After a simple in vitro treatment to reshuffle the disulfide bonds of hirudin, both staphylokinase and hirudin in HE-SAKK showed biological activities comparable with their parent molecules. This agent was capable of targeting thrombin-rich fibrin clots and inhibiting clot-bound thrombin activity. The time required for lysing 50% of fibrin clot in the absence or presence of fibrinogen was shortened 21 and 30%, respectively, with HE-SAKK in comparison with staphylokinase. In plasma clot studies, the HE-SAKK concentration required to achieve a comparable 50% clot lysis time was at least 12 times less than that of staphylokinase. Therefore, HE-SAKK is a promising thrombolytic agent with the capability to target thrombin-rich fibrin clots and to minimize clot reformation during fibrinolysis.
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Affiliation(s)
- Qun Lian
- Division of Cellular, Molecular and Microbial Biology, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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7
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Kamphausen S, Höltge N, Wirsching F, Morys-Wortmann C, Riester D, Goetz R, Thürk M, Schwienhorst A. Genetic algorithm for the design of molecules with desired properties. J Comput Aided Mol Des 2002; 16:551-67. [PMID: 12602950 DOI: 10.1023/a:1021928016359] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The design of molecules with desired properties is still a challenge because of the largely unpredictable end results. Computational methods can be used to assist and speed up this process. In particular, genetic algorithms have proved to be powerful tools with a wide range of applications, e.g. in the field of drug development. Here, we propose a new genetic algorithm that has been tailored to meet the demands of de novo drug design, i.e. efficient optimization based on small training sets that are analyzed in only a small number of design cycles. The efficiency of the design algorithm was demonstrated in the context of several different applications. First, RNA molecules were optimized with respect to folding energy. Second, a spinglass was optimized as a model system for the optimization of multiletter alphabet biopolymers such as peptides. Finally, the feasibility of the computer-assisted molecular design approach was demonstrated for the de novo construction of peptidic thrombin inhibitors using an iterative process of 4 design cycles of computer-guided optimization. Synthesis and experimental fitness determination of only 600 different compounds from a virtual library of more than 10(17) molecules was necessary to achieve this goal.
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Affiliation(s)
- Stefan Kamphausen
- Abteilung fuer Molekulare Genetik und Praeparative Molekularbiologie, Institut für Mikrobiologie und Genetik, Grisebachstr. 8, 37077 Goettingen, Germany
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8
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Wirsching F, Luge C, Schwienhorst A. Modular design of a novel chimeric protein with combined thrombin inhibitory activity and plasminogen-activating potential. Mol Genet Metab 2002; 75:250-9. [PMID: 11914037 DOI: 10.1006/mgme.2001.3292] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to design plasminogen activators with improved thrombolytic properties we sought to construct the bifunctional protein HLS-2 which combines both a plasminogen-activating and an anticoagulative activity. The chimeric protein comprises four elements: a derivative of thrombin inhibitor hirudin, a 6-amino acid spacer, the sequence of plasminogen-activator staphylokinase (Sak), and a 13-amino acid expression tag at the C-terminus. The gene of the fusion protein was obtained by SOE-PCR, cloned into pCANTAB5E, and expressed in E. coli BL21. HLS-2 was purified from periplasmatic extracts and characterized by Western blotting. Plasminogen-activation of HLS-2 and of Sak in equimolar mixtures with plasminogen showed near equivalence as measured by plasmin-mediated cleavage of chromogenic substrate S-2403. For catalytic amounts of plasminogen-activator, however, HLS-2 was less effective by a factor of 1.7. HLS-2 also inhibited both the amidolytic and the fibrinolytic activities of thrombin. Similar concentrations of either commercial HV1 (42 pmol/L) or HLS-2 (250 pmol/L) were required to halve the initial rate of thrombin reaction with fluorogenic substrate Tos-Gly-Pro-Arg-AMC, suggesting the retention of high-affinity inhibition of thrombin by the fusion protein sufficiently strong to substitute anticoagulative comedication during fibrinolytic treatment. The results provide a rationale for further testing the efficacy of HLS-2 for the lysis of platelet-rich arterial blood clots and for the prevention of reocclusion after thrombolysis.
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Affiliation(s)
- Frank Wirsching
- Abteilung fuer Molekulare Genetik und Praeparative Molekularbiologie, Institut fuer Mikrobiologie und Genetik, Grisebachstrasse 8, 37077 Goettingen, Germany
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9
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Hempel R, Wirsching F, Schober A, Schwienhorst A. A new reporter gene system suited for cell-free protein synthesis and high-throughput screening in small reaction volumes. Anal Biochem 2001; 297:177-82. [PMID: 11673885 DOI: 10.1006/abio.2001.5322] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The properties of M-hirudin as a new reporter gene system were examined using rabbit reticulocyte lysate for cell-free protein expression. In contrast to the luciferase gene, in vitro translation of M-hirudin is highly robust against changes in concentrations of K+ (and Rb+). In addition, M-hirudin can be detected very sensitively using a reasonably priced fluorimetric thrombin assay. To show that the new reporter gene system is well suited for (u)HTS-applications, cell-free synthesis as well as the fluorimetric assay of M-hirudin were carried out in nanotiter and microtiter plates, respectively.
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Affiliation(s)
- R Hempel
- Abteilung fuer Molekulare Genetik und Praeparative Molekularbiologie, Institut fuer Mikrobiologie und Genetik, Grisebachstrasse 8, Goettingen, 37077, Germany
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10
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Hempel R, Schmidt-Brauns J, Gebinoga M, Wirsching F, Schwienhorst A. Cation radius effects on cell-free translation in rabbit reticulocyte lysate. Biochem Biophys Res Commun 2001; 283:267-72. [PMID: 11327692 DOI: 10.1006/bbrc.2001.4766] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of monovalent cation concentrations on the translation was examined in the rabbit reticulocyte cell-free system. The translation of standard reporter gene luciferase was studied using different concentrations of LiCl, NaCl, KCl, RbCl, CsCl, NH(4)Cl, and (CH(3))(4)NCl and the acetates of Na(+), K(+), and NH4(+). Only the salts of K(+), Rb(+), and NH4(+) and to some minor extent of Cs(+) significantly supported translation. Optimum concentrations were dependent on the cation used. Optimum concentrations ranged between 40 mM (NH(4)Ac), 80 mM (KCl, NH(4)Cl), and 100 mM (RbCl, KAc). The maximum efficiency of translation depends on the ionic radius of the cation used. KCl and RbCl were superior to all other salts tested in stimulating in vitro translation. The results were confirmed, using a second reporter system, M-hirudin. Here, however, broad optima were observed with RbCl being slightly superior to KCl in supporting translation.
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Affiliation(s)
- R Hempel
- Abteilung fuer Molekulare Genetik und Praeparative Molekularbiologie, Institut fuer Mikrobiologie und Genetik, Grisebachstrasse 8, Goettingen, 37077, Germany
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11
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Tanaka AS, Silva MM, Torquato RJ, Noguti MA, Sampaio CA, Fritz H, Auerswald EA. Functional phage display of leech-derived tryptase inhibitor (LDTI): construction of a library and selection of thrombin inhibitors. FEBS Lett 1999; 458:11-6. [PMID: 10518924 DOI: 10.1016/s0014-5793(99)01106-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The recombinant phage antibody system pCANTAB 5E has been used to display functionally active leech-derived tryptase inhibitor (LDTI) on the tip of the filamentous M13 phage. A limited combinatorial library of 5.2 x 10(4) mutants was created with a synthetic LDTI gene, using a degenerated oligonucleotide and the pCANTAB 5E phagemid. The mutations were restricted to the P1-P4' positions of the reactive site. Fusion phages and appropriate host strains containing the phagemids were selected after binding to thrombin and DNA sequencing. The variants LDTI-2T (K8R, I9V, S10, K11W, P12A), LDTI-5T (K8R, I9V, S10, K11S, P12L) and LDTI-10T (K8R, I9L, S10, K11D, P12I) were produced with a Saccharomyces cerevisiae expression system. The new inhibitors, LDTI-2T and -5T, prolong the blood clotting time, inhibit thrombin (Ki 302 nM and 28 nM) and trypsin (Ki 6.4 nM and 2.1 nM) but not factor Xa, plasma kallikrein or neutrophil elastase. The variant LDTI-10T binds to thrombin but does not inhibit it. The relevant reactive site sequences of the thrombin inhibiting variants showed a strong preference for arginine in position P1 (K8R) and for valine in P1' (I9V). The data indicate further that LDTI-5T might be a model candidate for generation of active-site directed thrombin inhibitors and that LDTI in general may be useful to generate specific inhibitors suitable for a better understanding of enzyme-inhibitor interactions.
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Affiliation(s)
- A S Tanaka
- Departamento de Bioquímica, UNIFESP-EPM, São Paulo, Brazil.
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12
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Thurnheer MC, Zuercher AW, Miescher SM, Rudolf MP, Vogel M, Stadler BM. Molecular mimicry of the unidentified antigen of myeloma antibody IgE-ND. Eur J Immunol 1999; 29:2676-83. [PMID: 10508242 DOI: 10.1002/(sici)1521-4141(199909)29:09<2676::aid-immu2676>3.0.co;2-o] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Antigen-specific human IgE is in short supply. Thus, we sought to determine the yet unknown specificity of a widely available human IgE, namely the myeloma cell line U266-derived IgE-ND. For this purpose highly specific peptides able to mimic the putative antigen recognized by IgE-ND were isolated from phage-display random peptide libraries. Interestingly, we found linear sequence homologies of the IgE-ND-binding peptides with self antigens and a xenoantigen from Thiobacillus ferrooxidans. However, none of these antigens was recognized by IgE-ND. Nevertheless, our approach may be applied to identify antigen specificities of myeloma antibodies. Importantly, the mimotopes were anaphylactogenic in a histamine release assay using human basophils sensitized with IgE-ND. Thus, our mimotopes represent functional albeit synthetic antigens and may be used to study human antigen-specific IgE responses.
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Affiliation(s)
- M C Thurnheer
- Institute of Immunology and Allergology, University of Bern, Inselspital, Bern, Switzerland
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