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Acquasaliente L, Pierangelini A, Pagotto A, Pozzi N, De Filippis V. From haemadin to haemanorm: Synthesis and characterization of full-length haemadin from the leech Haemadipsa sylvestris and of a novel bivalent, highly potent thrombin inhibitor (haemanorm). Protein Sci 2023; 32:e4825. [PMID: 37924304 PMCID: PMC10683372 DOI: 10.1002/pro.4825] [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: 06/16/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 11/06/2023]
Abstract
Hirudin from Hirudo medicinalis is a bivalent α-Thrombin (αT) inhibitor, targeting the enzyme active site and exosite-I, and is currently used in anticoagulant therapy along with its simplified analogue hirulog. Haemadin, a small protein (57 amino acids) isolated from the land-living leech Haemadipsa sylvestris, selectively inhibits αT with a potency identical to that of recombinant hirudin (KI = 0.2 pM), with which it shares a common disulfide topology and overall fold. At variance with hirudin, haemadin targets exosite-II and therefore (besides the free protease) it also blocks thrombomodulin-bound αT without inhibiting the active intermediate meizothrombin, thus offering potential advantages over hirudin. Here, we produced in reasonably high yields and pharmaceutical purity (>98%) wild-type haemadin and the oxidation resistant Met5 → nor-Leucine analogue, both inhibiting αT with a KI of 0.2 pM. Thereafter, we used site-directed mutagenesis, spectroscopic, ligand-displacement, and Hydrogen/Deuterium Exchange-Mass Spectrometry techniques to map the αT regions relevant for the interaction with full-length haemadin and with the synthetic N- and C-terminal peptides Haem(1-10) and Haem(45-57). Haem(1-10) competitively binds to/inhibits αT active site (KI = 1.9 μM) and its potency was enhanced by 10-fold after Phe3 → β-Naphthylalanine exchange. Conversely to full-length haemadin, haem(45-57) displays intrinsic affinity for exosite-I (KD = 1.6 μM). Hence, we synthesized a peptide in which the sequences 1-9 and 45-57 were joined together through a 3-Glycine spacer to yield haemanorm, a highly potent (KI = 0.8 nM) inhibitor targeting αT active site and exosite-I. Haemanorm can be regarded as a novel class of hirulog-like αT inhibitors with potential pharmacological applications.
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Affiliation(s)
- Laura Acquasaliente
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
| | - Andrea Pierangelini
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
| | - Anna Pagotto
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
| | - Nicola Pozzi
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
- Department of Biochemistry and Molecular Biology, Edward A. Doisy Research CenterSaint Louis UniversitySt. LouisMissouriUSA
| | - Vincenzo De Filippis
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
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Goettig P, Koch NG, Budisa N. Non-Canonical Amino Acids in Analyses of Protease Structure and Function. Int J Mol Sci 2023; 24:14035. [PMID: 37762340 PMCID: PMC10531186 DOI: 10.3390/ijms241814035] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 09/29/2023] Open
Abstract
All known organisms encode 20 canonical amino acids by base triplets in the genetic code. The cellular translational machinery produces proteins consisting mainly of these amino acids. Several hundred natural amino acids serve important functions in metabolism, as scaffold molecules, and in signal transduction. New side chains are generated mainly by post-translational modifications, while others have altered backbones, such as the β- or γ-amino acids, or they undergo stereochemical inversion, e.g., in the case of D-amino acids. In addition, the number of non-canonical amino acids has further increased by chemical syntheses. Since many of these non-canonical amino acids confer resistance to proteolytic degradation, they are potential protease inhibitors and tools for specificity profiling studies in substrate optimization and enzyme inhibition. Other applications include in vitro and in vivo studies of enzyme kinetics, molecular interactions and bioimaging, to name a few. Amino acids with bio-orthogonal labels are particularly attractive, enabling various cross-link and click reactions for structure-functional studies. Here, we cover the latest developments in protease research with non-canonical amino acids, which opens up a great potential, e.g., for novel prodrugs activated by proteases or for other pharmaceutical compounds, some of which have already reached the clinical trial stage.
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Affiliation(s)
- Peter Goettig
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Paracelsus Medical University, Strubergasse 21, 5020 Salzburg, Austria
| | - Nikolaj G. Koch
- Biocatalysis Group, Technische Universität Berlin, 10623 Berlin, Germany;
- Bioanalytics Group, Institute of Biotechnology, Technische Universität Berlin, 10623 Berlin, Germany;
| | - Nediljko Budisa
- Bioanalytics Group, Institute of Biotechnology, Technische Universität Berlin, 10623 Berlin, Germany;
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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Huang Q, Gao Q, Chai X, Ren W, Zhang G, Kong Y, Zhang Y, Gao J, Lei X, Ma L. A novel thrombin inhibitory peptide discovered from leech using affinity chromatography combined with ultra-high performance liquid chromatography-high resolution mass spectroscopy. J Chromatogr B Analyt Technol Biomed Life Sci 2020; 1151:122153. [PMID: 32512533 DOI: 10.1016/j.jchromb.2020.122153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/21/2020] [Accepted: 05/09/2020] [Indexed: 02/08/2023]
Abstract
Thrombin (THR) inhibitors play an important role in the treatment of thrombotic diseases. This study established a THR-based bio-specific extraction coupled with affinity chromatography and ultra-high performance liquid chromatography-high resolution mass spectroscopy (UPLC-HR-MS) analysis method to screen and identify THR ligands in Leech. After evaluating the reliability of the screening method using positive control drug (hirudin), it was successfully used to screen the potential active constituents in leech. And a comprehensive analysis of the peptides in leech elution was performed by UPLC-HR-MS, a total of 34 peptides were identified. At the same time, anti-THR activity was explored and inferred by searching databases and published literature. As a result, six peptides were discovered to be potential active compounds in leech. Further, the six peptides were synthesized and in vitro enzymatic activity assay was performed. Finally, SYELPDGQVITIGNER was screened as an anti-THR peptide with an IC50 value of 255.75 µM and it was discovered for the first time from Whitmania pigra Whitman and Hirudo nipponica Whitman. The molecular docking study showed that THR inhibitory activity of the polypeptide was mainly attributed to the hydrogen bond interactions, van der Waals forces and electrostatic interactions interaction between polypeptide and THR. These results suggest that the polypeptide is a potential natural THR inhibitor that can be used as anticoagulant.
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Affiliation(s)
- Qiuyang Huang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
| | - Qian Gao
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
| | - Xiaoxin Chai
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
| | - Wei Ren
- Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou 646000, China
| | - Guifeng Zhang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Yingjun Kong
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Yan Zhang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianping Gao
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiongxin Lei
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Li Ma
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
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De Filippis V, Pozzi N, Acquasaliente L, Artusi I, Pontarollo G, Peterle D. Protein engineering by chemical methods: Incorporation of nonnatural amino acids as a tool for studying protein folding, stability, and function. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Vincenzo De Filippis
- Laboratory of Protein Chemistry, Department of Pharmaceutical & Pharmacological SciencesUniversity of Padua Padua Italy
| | - Nicola Pozzi
- Laboratory of Protein Chemistry, Department of Pharmaceutical & Pharmacological SciencesUniversity of Padua Padua Italy
| | - Laura Acquasaliente
- Laboratory of Protein Chemistry, Department of Pharmaceutical & Pharmacological SciencesUniversity of Padua Padua Italy
| | - Ilaria Artusi
- Laboratory of Protein Chemistry, Department of Pharmaceutical & Pharmacological SciencesUniversity of Padua Padua Italy
| | - Giulia Pontarollo
- Laboratory of Protein Chemistry, Department of Pharmaceutical & Pharmacological SciencesUniversity of Padua Padua Italy
| | - Daniele Peterle
- Laboratory of Protein Chemistry, Department of Pharmaceutical & Pharmacological SciencesUniversity of Padua Padua Italy
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De Filippis V, Acquasaliente L, Pontarollo G, Peterle D. Noncoded amino acids in protein engineering: Structure-activity relationship studies of hirudin-thrombin interaction. Biotechnol Appl Biochem 2018; 65:69-80. [DOI: 10.1002/bab.1632] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 12/06/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Vincenzo De Filippis
- Laboratory of Protein Chemistry; Department of Pharmaceutical & Pharmacological Sciences; University of Padua; Padua Italy
| | - Laura Acquasaliente
- Laboratory of Protein Chemistry; Department of Pharmaceutical & Pharmacological Sciences; University of Padua; Padua Italy
| | - Giulia Pontarollo
- Laboratory of Protein Chemistry; Department of Pharmaceutical & Pharmacological Sciences; University of Padua; Padua Italy
| | - Daniele Peterle
- Laboratory of Protein Chemistry; Department of Pharmaceutical & Pharmacological Sciences; University of Padua; Padua Italy
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Betush RJ, Urban JM, Nilsson BL. Balancing hydrophobicity and sequence pattern to influence self-assembly of amphipathic peptides. Biopolymers 2018; 110. [PMID: 29292825 DOI: 10.1002/bip.23099] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/01/2017] [Accepted: 12/04/2017] [Indexed: 01/25/2023]
Abstract
Amphipathic peptides with alternating polar and nonpolar amino acid sequences efficiently self-assemble into functional β-sheet fibrils as long as the nonpolar residues have sufficient hydrophobicity. For example, the Ac-(FKFE)2 -NH2 peptide rapidly self-assembles into β-sheet bilayer nanoribbons, while Ac-(AKAE)2 -NH2 fails to self-assemble under similar conditions due to the significantly reduced hydrophobicity and β-sheet propensity of Ala relative to Phe. Herein, we systematically explore the effect of substituting only two of the four Ala residues at various positions in the Ac-(AKAE)2 -NH2 peptide with amino acids of increasing hydrophobicity, β-sheet potential, and surface area (including Phe, 1-naphthylalanine (1-Nal), 2-naphthylalanine (2-Nal), cyclohexylalanine (Cha), and pentafluorophenylalanine (F5 -Phe)) on the self-assembly propensity of the resulting sequences. It was found that double Phe variants, regardless of the position of substitution, failed to self-assemble under the conditions used in this study. In contrast, all double 1-Nal and 2-Nal variants readily self-assembled, albeit at differing rates depending on the substitution patterns. To determine whether this was due to hydrophobicity or side chain surface area, we also prepared double Cha and F5 -Phe variant peptides (both side chain groups are more hydrophobic than Phe). Each of these variants also underwent effective self-assembly, with the aromatic F5 -Phe peptides doing so with greater efficiency. These findings provide insight into the role of amino acid hydrophobicity and sequence pattern on self-assembly proclivity of amphipathic peptides and on how targeted substitutions of nonpolar residues in these sequences can be exploited to tune the characteristics of the resulting self-assembled materials.
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Affiliation(s)
- Ria J Betush
- Department of Chemistry, Gannon University, Erie, Pennsylvania
| | - Jennifer M Urban
- Department of Chemistry, University of Rochester, Rochester, New York
| | - Bradley L Nilsson
- Department of Chemistry, University of Rochester, Rochester, New York
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Pontarollo G, Acquasaliente L, Peterle D, Frasson R, Artusi I, De Filippis V. Non-canonical proteolytic activation of human prothrombin by subtilisin from Bacillus subtilis may shift the procoagulant-anticoagulant equilibrium toward thrombosis. J Biol Chem 2017; 292:15161-15179. [PMID: 28684417 DOI: 10.1074/jbc.m117.795245] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 06/28/2017] [Indexed: 12/26/2022] Open
Abstract
Blood coagulation is a finely regulated physiological process culminating with the factor Xa (FXa)-mediated conversion of the prothrombin (ProT) zymogen to active α-thrombin (αT). In the prothrombinase complex on the platelet surface, FXa cleaves ProT at Arg-271, generating the inactive precursor prethrombin-2 (Pre2), which is further attacked at Arg-320-Ile-321 to yield mature αT. Whereas the mechanism of physiological ProT activation has been elucidated in great detail, little is known about the role of bacterial proteases, possibly released in the bloodstream during infection, in inducing blood coagulation by direct proteolytic ProT activation. This knowledge gap is particularly concerning, as bacterial infections are frequently complicated by severe coagulopathies. Here, we show that addition of subtilisin (50 nm to 2 μm), a serine protease secreted by the non-pathogenic bacterium Bacillus subtilis, induces plasma clotting by proteolytically converting ProT into active σPre2, a nicked Pre2 derivative with a single cleaved Ala-470-Asn-471 bond. Notably, we found that this non-canonical cleavage at Ala-470-Asn-471 is instrumental for the onset of catalysis in σPre2, which was, however, reduced about 100-200-fold compared with αT. Of note, σPre2 could generate fibrin clots from fibrinogen, either in solution or in blood plasma, and could aggregate human platelets, either isolated or in whole blood. Our findings demonstrate that alternative cleavage of ProT by proteases, even by those secreted by non-virulent bacteria such as B. subtilis, can shift the delicate procoagulant-anticoagulant equilibrium toward thrombosis.
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Affiliation(s)
- Giulia Pontarollo
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Laura Acquasaliente
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Daniele Peterle
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Roberta Frasson
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Ilaria Artusi
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Vincenzo De Filippis
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
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8
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Rohrbach F, Schäfer F, Fichte MAH, Pfeiffer F, Müller J, Pötzsch B, Heckel A, Mayer G. Aptamerbasiertes Caging zur selektiven Maskierung von Proteindomänen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201306686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Rohrbach F, Schäfer F, Fichte MAH, Pfeiffer F, Müller J, Pötzsch B, Heckel A, Mayer G. Aptamer-guided caging for selective masking of protein domains. Angew Chem Int Ed Engl 2013; 52:11912-5. [PMID: 24127310 DOI: 10.1002/anie.201306686] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 08/30/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Falk Rohrbach
- Life and Medical Sciences Institute, Gerhard Domagk-Strasse 1, 53121 Bonn (Germany) http://www.mayerlab.de
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Cuccioloni M, Mozzicafreddo M, Bonfili L, Cecarini V, Eleuteri AM, Angeletti M. Natural occurring polyphenols as template for drug design. Focus on serine proteases. Chem Biol Drug Des 2009; 74:1-15. [PMID: 19519739 DOI: 10.1111/j.1747-0285.2009.00836.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Several major physio-pathological processes, including cancer, inflammatory states and thrombosis, are all strongly dependent upon the fine regulation of proteolytic enzyme activities, and dramatic are the consequences of unbalanced equilibria between enzymes and their cognate inhibitors. In this perspective, the discovery of small-molecule ligands able to modulate catalytic activities has a massive therapeutic potential and is a stimulating goal. Numerous recent experimental evidences revealed that proteolytic enzymes can be opportunely targeted, reporting on small ligands capable of binding to these biological macromolecules with drug-like potencies, and primarily with comparable (or even higher) efficiency with respect to their endogenous binding partner. In particular, natural occurring polyphenols and their derivatives recently disclosed these intriguing abilities, making them promising templates for drug design and development. In this review, we compared the inhibitory capacities of a set of monomeric polyphenols toward serine proteases activity, and finally summarized the data with an emphasis on the derivation of a pharmacophore model.
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Affiliation(s)
- Massimiliano Cuccioloni
- Department of Molecular, Cellular and Animal Biology, University of Camerino, Via Gentile III da Varano, Camerino (MC), Italy.
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Kolodzeiskaya MV, Sokolovskaya LI, Volkov GL. Role of A-chain in functioning of the active site of human alpha-thrombin. BIOCHEMISTRY (MOSCOW) 2008; 73:237-44. [PMID: 18393757 DOI: 10.1134/s0006297908030012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review summarizes current data suggesting that A-chain of the human alpha-thrombin molecule plays a role of allosteric effector in catalytic reactions with various substrates. Special attention is paid to the relationship between A-chain structure and catalytic activity of thrombin. The existence of this relationship is based on studies of natural mutation of A-chain of the alpha-thrombin molecule. Use of molecular and essential dynamics confirmed the role of A-chain in changes of conformation and catalytic properties of this enzyme; these changes involve residues located in the specificity sites and some inserting loops. Current knowledge on structure and properties of thrombin can be used for the development of new antithrombin agents.
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Affiliation(s)
- M V Kolodzeiskaya
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine
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De Filippis V, Frasson R, Fontana A. 3-Nitrotyrosine as a spectroscopic probe for investigating protein protein interactions. Protein Sci 2006; 15:976-86. [PMID: 16641485 PMCID: PMC2242503 DOI: 10.1110/ps.051957006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
3-Nitrotyrosine (NT) is approximately 10(3)-fold more acidic than Tyr, and its absorption properties are strongly pH-dependent. NT absorbs radiation in the wavelength range where Tyr and Trp emit fluorescence (300-450 nm), and it is essentially nonfluorescent. Therefore, NT may function as an energy acceptor in resonance energy transfer (FRET) studies for investigating ligand protein interactions. Here, the potentialities of NT were tested on the hirudin thrombin system, a well-characterized protease inhibitor pair of key pharmacological importance. We synthesized two analogs of the N-terminal domain (residues 1-47) of hirudin: Y3NT, in which Tyr3 was replaced by NT, and S2R/Y3NT, containing the substitutions Ser2 --> Arg and Tyr3 --> NT. The binding of these analogs to thrombin was investigated at pH 8 by FRET and UV/Vis-absorption spectroscopy. Upon hirudin binding, the fluorescence of thrombin was reduced by approximately 50%, due to the energy transfer occurring between the Trp residues of the enzyme (i.e., the donors) and the single NT of the inhibitor (i.e., the acceptor). The changes in the absorption spectra of the enzyme inhibitor complex indicate that the phenate moiety of NT in the free state becomes protonated to phenol in the thrombin-bound form. Our results indicate that the incorporation of NT can be effectively used to detect protein protein interactions with sensitivity in the low nanomolar range, to uncover subtle structural features at the ligand protein interface, and to obtain reliable Kd values for structure activity relationship studies. Furthermore, advances in chemical and genetic methods, useful for incorporating noncoded amino acids into proteins, highlight the broad applicability of NT in biotechnology and pharmacological screening.
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Affiliation(s)
- Vincenzo De Filippis
- Department of Pharmaceutical Sciences and CRIBI Biotechnology Center, University of Padua, I-35131 Padua, Italy.
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De Filippis V, De Dea E, Lucatello F, Frasson R. Effect of Na+ binding on the conformation, stability and molecular recognition properties of thrombin. Biochem J 2006; 390:485-92. [PMID: 15971999 PMCID: PMC1198928 DOI: 10.1042/bj20050252] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the present work, the effect of Na+ binding on the conformational, stability and molecular recognition properties of thrombin was investigated. The binding of Na+ reduces the CD signal in the far-UV region, while increasing the intensity of the near-UV CD and fluorescence spectra. These spectroscopic changes have been assigned to perturbations in the environment of aromatic residues at the level of the S2 and S3 sites, as a result of global rigidification of the thrombin molecule. Indeed, the Na+-bound form is more stable to urea denaturation than the Na+-free form by approximately 2 kcal/mol (1 cal identical with 4.184 J). Notably, the effects of cation binding on thrombin conformation and stability are specific to Na+ and parallel the affinity order of univalent cations for the enzyme. The Na+-bound form is even more resistant to limited proteolysis by subtilisin, at the level of the 148-loop, which is suggestive of the more rigid conformation this segment assumes in the 'fast' form. Finally, we have used hirudin fragment 1-47 as a molecular probe of the conformation of thrombin recognition sites in the fast and 'slow' form. From the effects of amino acid substitutions on the affinity of fragment 1-47 for the enzyme allosteric forms, we concluded that the specificity sites of thrombin in the Na+-bound form are in a more open and permissible conformation, compared with the more closed structure they assume in the slow form. Taken together, our results indicate that the binding of Na+ to thrombin serves to stabilize the enzyme into a more open and rigid conformation.
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Affiliation(s)
- Vincenzo De Filippis
- Department of Pharmaceutical Sciences and CRIBI Biotechnology Center, University of Padua, via F. Marzolo 5, I-35131 Padua, Italy
- To whom correspondence should be addressed (email )
| | - Elisa De Dea
- Department of Pharmaceutical Sciences and CRIBI Biotechnology Center, University of Padua, via F. Marzolo 5, I-35131 Padua, Italy
| | - Filippo Lucatello
- Department of Pharmaceutical Sciences and CRIBI Biotechnology Center, University of Padua, via F. Marzolo 5, I-35131 Padua, Italy
| | - Roberta Frasson
- Department of Pharmaceutical Sciences and CRIBI Biotechnology Center, University of Padua, via F. Marzolo 5, I-35131 Padua, Italy
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Menssen HD, Melber K, Brandt N, Thiel E. The use of hirudin as universal anticoagulant in haematology, clinical chemistry and blood grouping. Clin Chem Lab Med 2001; 39:1267-77. [PMID: 11798089 DOI: 10.1515/cclm.2001.204] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Undesirable interactions between anticoagulants and diagnostic test kit procedures so far have prevented the development of a single uniform blood sampling tube. Contrary to K2-EDTA, heparin and other anticoagulants, hirudin only minimally alters blood cells and dissolved blood constituents, thus qualifying as a universal anticoagulant for diagnostic purposes. Automated complete blood counts, automated analyses of clinical chemistry analytes and immunohaematology were performed from hirudinised and routinely processed blood obtained from healthy volunteers (n=35) and hospitalised patients (n=45). Hirudin (400 ATU/ml blood) sufficiently anticoagulated blood for diagnostic purposes. The measurements of automated complete blood counts obtained from K2-EDTA-anticoagulated and hirudinised blood correlated significantly as did the measurements of 24 clinical chemistry analytes from hirudinised plasma and serum. Regression analysis revealed that the results of complete blood counts and clinical chemistry tests were predictable from the respective measurements from hirudinised blood (p=0.001). Immunohaematological tests and cross-matching from hirudinised and native blood of the same donors gave identical results. Single clotting factors, but not global coagulation analytes, could be measured from hirudinised blood. Therefore, a universal hirudin-containing blood sampling tube could be designed for automated analysis of haematological, serological and clinical chemistry analytes.
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Affiliation(s)
- H D Menssen
- Department of Internal Medicine III Haematology, Oncology and Transfusion Medicine, Universitätsklinikum Benjamin Franklin, Berlin, Germany.
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Borsody MK, DeGiovanni GM, Marton LS, Macdonald RL, Weir B. Thrombin reduces cerebral arterial contractions caused by cerebrospinal fluid from patients with subarachnoid hemorrhage. Stroke 2000; 31:2149-56. [PMID: 10978044 DOI: 10.1161/01.str.31.9.2149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE We observed that the second application of cerebrospinal fluid (CSF) from subarachnoid hemorrhage (SAH) patients onto cerebral arterial segments in vitro produces a greater contraction than does the initial application. It was hypothesized that the difference between the first and second applications of SAH CSF was due to the activity of thrombin. METHODS Canine vertebrobasilar artery was removed under general anesthesia, cut into rings, and suspended in tissue culture baths so as to measure isometric tension. CSF was taken from patients 1 to 3 days after SAH via ventricular drains. CSF was administered in 10(-5) to 10(-1) dilutions. The thrombin antagonist hirudin (5 U) was administered before CSF in some experiments. The arterial tension response to pure oxyhemoglobin (10(-4) to 3.2 g/dL) and thrombin (10(-4) to 3.2 U/mL), administered alone or in combination, was also examined. RESULTS Hirudin increased arterial tension generated on the initial application of SAH CSF but had no effect on the tension generated by the second application of the SAH CSF, suggesting that thrombin limits the tension generated by vasoconstrictive agents in the CSF. Thrombin and pure oxyhemoglobin administered together produced less tension than that generated in response to oxyhemoglobin administered alone; no additive response was observed by coadministering the 2 vasoconstrictive agents. CONCLUSIONS In the presence of oxyhemoglobin, thrombin acts to reduce cerebral arterial tension. This interaction between thrombin and hemoglobin may account for the observation that the second application of CSF from SAH patients onto cerebral arterial segments in vitro produces a greater contraction than does the initial application.
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Affiliation(s)
- M K Borsody
- Section of Neurosurgery, Department of Surgery, University of Chicago Medical Center and Pritzker School of Medicine, Chicago, IL, USA
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