1
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Maddur AA, Voehler M, Panizzi P, Meiler J, Bock PE, Verhamme IM. Mapping of the fibrinogen-binding site on the staphylocoagulase C-terminal repeat region. J Biol Chem 2021; 298:101493. [PMID: 34915025 PMCID: PMC8761706 DOI: 10.1016/j.jbc.2021.101493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 12/08/2021] [Indexed: 01/12/2023] Open
Abstract
Fibrin (Fbn) deposits are a hallmark of staphylocoagulase (SC)-positive endocarditis. Binding of the N terminus of Staphylococcus aureus SC to host prothrombin triggers formation of an active SC·prothrombin∗ complex that cleaves host fibrinogen to Fbn. In addition, the C-terminal domain of the prototypical SC contains one pseudorepeat (PR) and seven repeats (R1 → R7) that bind fibrinogen/Fbn fragment D (frag D) by a mechanism that is unclear. Here, we define affinities and stoichiometries of frag D binding to C-terminal SC constructs, using fluorescence equilibrium binding, NMR titration, alanine scanning, and native PAGE. We found that constructs containing the PR and single repeats bound frag D with KD ∼50 to 130 nM and a 1:1 stoichiometry, indicating a conserved binding site bridging the PR and each repeat. NMR titration of PR-R7 with frag D revealed that residues 22 to 49, bridging PR and R7, constituted the minimal peptide (MP) for binding, corroborated by alanine scanning, and binding of labeled MP to frag D. MP alignment with the PR-R and inter-repeat junctions identified critical conserved residues. Full-length PR-(R1 → R7) bound frag D with KD ∼20 nM and a stoichiometry of 1:5, whereas constructs containing the PR and various three repeats competed with PR-(R1 → R7) for frag D binding, with a 1:3 stoichiometry. These findings are consistent with binding at PR-R and R-R junctions with modest inter-repeat sequence variability. CD of PR-R7 and PR-(R1 → R7) suggested a disordered flexible structure, allowing binding of multiple fibrin(ogen) molecules. Taken together, these results provide insights into pathogen localization on host fibrin networks.
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Affiliation(s)
- Ashoka A. Maddur
- FUJIFILM Diosynth Biotechnologies, College Station, Texas, USA,For correspondence: Ingrid M. Verhamme; Ashoka A. Maddur
| | - Markus Voehler
- Vanderbilt Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Peter Panizzi
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, USA
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA,Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Paul E. Bock
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Ingrid M. Verhamme
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA,For correspondence: Ingrid M. Verhamme; Ashoka A. Maddur
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2
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Kearney KJ, Ariëns RAS, Macrae FL. The Role of Fibrin(ogen) in Wound Healing and Infection Control. Semin Thromb Hemost 2021; 48:174-187. [PMID: 34428799 DOI: 10.1055/s-0041-1732467] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Fibrinogen, one of the most abundant plasma proteins playing a key role in hemostasis, is an important modulator of wound healing and host defense against microbes. In the current review, we address the role of fibrin(ogen) throughout the process of wound healing and subsequent tissue repair. Initially fibrin(ogen) acts as a provisional matrix supporting incoming leukocytes and acting as reservoir for growth factors. It later goes on to support re-epithelialization, angiogenesis, and fibroplasia. Importantly, removal of fibrin(ogen) from the wound is essential for wound healing to progress. We also discuss how fibrin(ogen) functions through several mechanisms to protect the host against bacterial infection by providing a physical barrier, entrapment of bacteria in fibrin(ogen) networks, and by directing immune cell function. The central role of fibrin(ogen) in defense against bacterial infection has made it a target of bacterial proteins, evolved to interact with fibrin(ogen) to manipulate clot formation and degradation for the purpose of promoting microbial virulence and survival. Further understanding of the dual roles of fibrin(ogen) in wound healing and infection could provide novel means of therapy to improve recovery from surgical or chronic wounds and help to prevent infection from highly virulent bacterial strains, including those resistant to antibiotics.
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Affiliation(s)
- Katherine J Kearney
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Robert A S Ariëns
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom.,Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Fraser L Macrae
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
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3
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Maddur AA, Kroh HK, Aschenbrenner ME, Gibson BHY, Panizzi P, Sheehan JH, Meiler J, Bock PE, Verhamme IM. Specificity and affinity of the N-terminal residues in staphylocoagulase in binding to prothrombin. J Biol Chem 2020; 295:5614-5625. [PMID: 32156702 PMCID: PMC7186164 DOI: 10.1074/jbc.ra120.012588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/09/2020] [Indexed: 11/06/2022] Open
Abstract
In Staphylococcus aureus-caused endocarditis, the pathogen secretes staphylocoagulase (SC), thereby activating human prothrombin (ProT) and evading immune clearance. A previous structural comparison of the SC(1-325) fragment bound to thrombin and its inactive precursor prethrombin 2 has indicated that SC activates ProT by inserting its N-terminal dipeptide Ile1-Val2 into the ProT Ile16 pocket, forming a salt bridge with ProT's Asp194, thereby stabilizing the active conformation. We hypothesized that these N-terminal SC residues modulate ProT binding and activation. Here, we generated labeled SC(1-246) as a probe for competitively defining the affinities of N-terminal SC(1-246) variants preselected by modeling. Using ProT(R155Q,R271Q,R284Q) (ProTQQQ), a variant refractory to prothrombinase- or thrombin-mediated cleavage, we observed variant affinities between ∼1 and 650 nm and activation potencies ranging from 1.8-fold that of WT SC(1-246) to complete loss of function. Substrate binding to ProTQQQ caused allosteric tightening of the affinity of most SC(1-246) variants, consistent with zymogen activation through occupation of the specificity pocket. Conservative changes at positions 1 and 2 were well-tolerated, with Val1-Val2, Ile1-Ala2, and Leu1-Val2 variants exhibiting ProTQQQ affinity and activation potency comparable with WT SC(1-246). Weaker binding variants typically had reduced activation rates, although at near-saturating ProTQQQ levels, several variants exhibited limiting rates similar to or higher than that of WT SC(1-246). The Ile16 pocket in ProTQQQ appears to favor nonpolar, nonaromatic residues at SC positions 1 and 2. Our results suggest that SC variants other than WT Ile1-Val2-Thr3 might emerge with similar ProT-activating efficiency.
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Affiliation(s)
- Ashoka A Maddur
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561.
| | - Heather K Kroh
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561
| | - Mary E Aschenbrenner
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561
| | - Breanne H Y Gibson
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561
| | - Peter Panizzi
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, Alabama 36849
| | - Jonathan H Sheehan
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232; Institute for Drug Discovery, Departments of Chemistry and Computer Science, Leipzig University Medical School, SAC 04103 Leipzig, Germany
| | - Paul E Bock
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561
| | - Ingrid M Verhamme
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561.
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4
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Mican J, Toul M, Bednar D, Damborsky J. Structural Biology and Protein Engineering of Thrombolytics. Comput Struct Biotechnol J 2019; 17:917-938. [PMID: 31360331 PMCID: PMC6637190 DOI: 10.1016/j.csbj.2019.06.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/25/2019] [Accepted: 06/27/2019] [Indexed: 12/22/2022] Open
Abstract
Myocardial infarction and ischemic stroke are the most frequent causes of death or disability worldwide. Due to their ability to dissolve blood clots, the thrombolytics are frequently used for their treatment. Improving the effectiveness of thrombolytics for clinical uses is of great interest. The knowledge of the multiple roles of the endogenous thrombolytics and the fibrinolytic system grows continuously. The effects of thrombolytics on the alteration of the nervous system and the regulation of the cell migration offer promising novel uses for treating neurodegenerative disorders or targeting cancer metastasis. However, secondary activities of thrombolytics may lead to life-threatening side-effects such as intracranial bleeding and neurotoxicity. Here we provide a structural biology perspective on various thrombolytic enzymes and their key properties: (i) effectiveness of clot lysis, (ii) affinity and specificity towards fibrin, (iii) biological half-life, (iv) mechanisms of activation/inhibition, and (v) risks of side effects. This information needs to be carefully considered while establishing protein engineering strategies aiming at the development of novel thrombolytics. Current trends and perspectives are discussed, including the screening for novel enzymes and small molecules, the enhancement of fibrin specificity by protein engineering, the suppression of interactions with native receptors, liposomal encapsulation and targeted release, the application of adjuvants, and the development of improved production systems.
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Key Words
- EGF, Epidermal growth factor domain
- F, Fibrin binding finger domain
- Fibrinolysis
- K, Kringle domain
- LRP1, Low-density lipoprotein receptor-related protein 1
- MR, Mannose receptor
- NMDAR, N-methyl-D-aspartate receptor
- P, Proteolytic domain
- PAI-1, Inhibitor of tissue plasminogen activator
- Plg, Plasminogen
- Plm, Plasmin
- RAP, Receptor antagonist protein
- SAK, Staphylokinase
- SK, Streptokinase
- Staphylokinase
- Streptokinase
- Thrombolysis
- Tissue plasminogen activator
- Urokinase
- t-PA, Tissue plasminogen activator
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Affiliation(s)
- Jan Mican
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
| | - Martin Toul
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
| | - David Bednar
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
| | - Jiri Damborsky
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
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5
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Abstract
Proteases drive the life cycle of all proteins, ensuring the transportation and activation of newly minted, would-be proteins into their functional form while recycling spent or unneeded proteins. Far from their image as engines of protein digestion, proteases play fundamental roles in basic physiology and regulation at multiple levels of systems biology. Proteases are intimately associated with disease and modulation of proteolytic activity is the presumed target for successful therapeutics. "Proteases: Pivot Points in Functional Proteomics" examines the crucial roles of proteolysis across a wide range of physiological processes and diseases. The existing and potential impacts of proteolysis-related activity on drug and biomarker development are presented in detail. All told the decisive roles of proteases in four major categories comprising 23 separate subcategories are addressed. Within this construct, 15 sets of subject-specific, tabulated data are presented that include identification of proteases, protease inhibitors, substrates, and their actions. Said data are derived from and confirmed by over 300 references. Cross comparison of datasets indicates that proteases, their inhibitors/promoters and substrates intersect over a range of physiological processes and diseases, both chronic and pathogenic. Indeed, "Proteases: Pivot Points …" closes by dramatizing this very point through association of (pro)Thrombin and Fibrin(ogen) with: hemostasis, innate immunity, cardiovascular and metabolic disease, cancer, neurodegeneration, and bacterial self-defense.
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Affiliation(s)
- Ingrid M Verhamme
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.
| | - Sarah E Leonard
- Chemical and Biomolecular Engineering, University of Illinois Champaign-Urbana School of Chemical Sciences, Champaign, IL, USA
| | - Ray C Perkins
- New Liberty Proteomics Corporation, New Liberty, KY, USA.
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6
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Mukherjee P, Leman LJ, Griffin JH, Ghadiri MR. Design of a DNA-Programmed Plasminogen Activator. J Am Chem Soc 2018; 140:15516-15524. [PMID: 30347143 DOI: 10.1021/jacs.8b10166] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although the functional specificity and catalytic versatility of enzymes have been exploited in numerous settings, controlling the spatial and temporal activity of enzymes remains challenging. Here we describe an approach for programming the function of streptokinase (SK), a protein that is clinically used as a blood "clot buster" therapeutic. We show that the fibrinolytic activity resulting from the binding of SK to the plasma proenzyme plasminogen (Pg) can be effectively regulated (turned "OFF" and "ON") by installing an intrasteric regulatory feature using a DNA-linked protease inhibitor modification. We describe the design rationale, synthetic approach, and functional characterization of two generations of intrasterically regulated SK-Pg constructs and demonstrate dose-dependent and sequence-specific temporal control in fibrinolytic activity in response to short predesignated DNA inputs. The studies described establish the feasibility of a new enzyme-programming approach and serves as a step toward advancing a new generation of programmable enzyme therapeutics.
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Affiliation(s)
- Purba Mukherjee
- Department of Chemistry , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - Luke J Leman
- Department of Chemistry , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - John H Griffin
- Department of Molecular Medicine , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - M Reza Ghadiri
- Department of Chemistry , The Scripps Research Institute , La Jolla , California 92037 , United States.,The Skaggs Institute of Chemical Biology , The Scripps Research Institute , La Jolla , California 92037 , United States
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7
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Voehler M, Ashoka MA, Meiler J, Bock PE. Carbon and amide detect backbone assignment methods of a novel repeat protein from the staphylocoagulase in S. aureus. BIOMOLECULAR NMR ASSIGNMENTS 2017; 11:243-249. [PMID: 28819722 PMCID: PMC6057470 DOI: 10.1007/s12104-017-9757-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/05/2017] [Indexed: 06/07/2023]
Abstract
The C-terminal repeat domain of staphylocoagulase that is secreted by the S. aureus is believed to play an important role interacting with fibrinogen and promotes blood clotting. To study this interaction by NMR, full assignment of each amide residue in the HSQC spectrum was required. Despite of the short sequence of the repeat construct, the HSQC spectrum contained a substantial amount of overlapped and exchange broadened resonances, indicating little secondary or tertiary structure. This caused severe problems while using the conventional, amide based NMR method for the backbone assignment. With the growing interest in small apparently disordered proteins, these issues are being faced more frequently. An alternative strategy to improve the backbone assignment capability involved carbon direct detection methods. Circumventing the amide proton detection offers a larger signal dispersion and more uniform signal intensity. For peptides with higher concentrations and in combination with the cold carbon channels of new cryoprobes, higher fields, and sufficiently long relaxation times, the disadvantage of the lower sensitivity of the 13C nucleus can be overcome. Another advantage of this method is the assignment of the proline backbone residues. Complete assignment with the carbon-detected strategy was achieved with a set of only two 3D, one 2D, and a HNCO measurement, which was necessary to translate the information to the HSQC spectrum.
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Affiliation(s)
- Markus Voehler
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232-8725, USA.
| | - Maddur Appajaiah Ashoka
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Jens Meiler
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232-8725, USA
| | - Paul E Bock
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
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8
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Davis RW, Eggleston H, Johnson F, Nahrendorf M, Bock PE, Peterson T, Panizzi P. In Vivo Tracking of Streptococcal Infections of Subcutaneous Origin in a Murine Model. Mol Imaging Biol 2016; 17:793-801. [PMID: 25921659 DOI: 10.1007/s11307-015-0856-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE Generation of plasmin in vivo by Streptococcus pyogenes is thought to localize the active protease complexes to the pathogen surface to aid in tissue dissemination. Here, we chose to follow cutaneous streptococcal infections by the use of non-invasive bioluminescence imaging to determine if this pathogen can be followed by this approach and the extent of bacterial spread in the absence of canonical plasminogen activation by streptokinase. PROCEDURES Mice were injected subcutaneously with either bioluminescent strains of streptococci, namely Xen20 and Xen10 or S. pyogenes ALAB49. Bioluminescence imaging was performed daily and results were correlated with microbiological and histological analyses. RESULTS Comparative analysis of chronologic non-invasive datasets indicated that Xen20 did not disseminate from the initial infection site. Contrary to this, microbiological and histological analyses of Xen20 mice for total bacterial burden indicated sepsis and widespread pathogen involvement. CONCLUSIONS The use of bioluminescence in microbe-based studies requires genomic and pathologic characterization to correlate imaging results with underlying pathology.
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Affiliation(s)
- Richard W Davis
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, 4306 Walker Building, Auburn, AL, 36849, USA
| | - Heather Eggleston
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, 4306 Walker Building, Auburn, AL, 36849, USA
| | - Frances Johnson
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, 4306 Walker Building, Auburn, AL, 36849, USA
| | - Matthias Nahrendorf
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Simches Research Building, 185 Cambridge St., Boston, MA, 02114, USA
| | - Paul E Bock
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Tiffany Peterson
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, 4306 Walker Building, Auburn, AL, 36849, USA
| | - Peter Panizzi
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, 4306 Walker Building, Auburn, AL, 36849, USA.
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9
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Abstract
Group A streptococci (GAS) express soluble and surface-bound virulence factors. Secreted streptokinase (SK) allelic variants exhibit varying abilities to activate host plasminogen (Pg), and GAS pathogenicity is associated with Pg activation and localization of the resulting plasmin (Pm) on the bacterial surface to promote dissemination. The various mechanisms by which GAS usurp the host proteolytic system are discussed, including the molecular sexuality mechanism of conformational activation of the Pg zymogen (Pg*) and subsequent proteolytic activation of substrate Pg by the S•KPg* and SK•Pm catalytic complexes. Substantial progress has been made to delineate both processes in a unified mechanism. Pm coats the bacteria by direct and indirect binding pathways involving plasminogen-binding group A streptococcal M-like (PAM) protein and host fibrin(ogen). Transgenic mouse models using human Pg are being optimized to mimic infections by SK variants in humans and to define in vivo combined mechanisms of these variants and PAM.
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Affiliation(s)
- I M Verhamme
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - P R Panizzi
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - P E Bock
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
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10
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Verhamme IM, Bock PE. Rapid binding of plasminogen to streptokinase in a catalytic complex reveals a three-step mechanism. J Biol Chem 2014; 289:28006-18. [PMID: 25138220 DOI: 10.1074/jbc.m114.589077] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rapid kinetics demonstrate a three-step pathway of streptokinase (SK) binding to plasminogen (Pg), the zymogen of plasmin (Pm). Formation of a fluorescently silent encounter complex is followed by two conformational tightening steps reported by fluorescence quenches. Forward reactions were defined by time courses of biphasic quenching during complex formation between SK or its COOH-terminal Lys(414) deletion mutant (SKΔK414) and active site-labeled [Lys]Pg ([5-(acetamido)fluorescein]-D-Phe-Phe-Arg-[Lys]Pg ([5F]FFR-[Lys]Pg)) and by the SK dependences of the quench rates. Active site-blocked Pm rapidly displaced [5F]FFR-[Lys]Pg from the complex. The encounter and final SK ·[5F]FFR-[Lys]Pg complexes were weakened similarly by SK Lys(414) deletion and blocking of lysine-binding sites (LBSs) on Pg kringles with 6-aminohexanoic acid or benzamidine. Forward and reverse rates for both tightening steps were unaffected by 6-aminohexanoic acid, whereas benzamidine released constraints on the first conformational tightening. This indicated that binding of SK Lys(414) to Pg kringle 4 plays a role in recognition of Pg by SK. The substantially lower affinity of the final SK · Pg complex compared with SK · Pm is characterized by a ∼ 25-fold weaker encounter complex and ∼ 40-fold faster off-rates for the second conformational step. The results suggest that effective Pg encounter requires SK Lys(414) engagement and significant non-LBS interactions with the protease domain, whereas Pm binding additionally requires contributions of other lysines. This difference may be responsible for the lower affinity of the SK · Pg complex and the expression of a weaker "pro"-exosite for binding of a second Pg in the substrate mode compared with SK · Pm.
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Affiliation(s)
- Ingrid M Verhamme
- From the Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Paul E Bock
- From the Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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11
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Nolan M, Bouldin SD, Bock PE. Full time course kinetics of the streptokinase-plasminogen activation pathway. J Biol Chem 2013; 288:29482-93. [PMID: 23970549 DOI: 10.1074/jbc.m113.477935] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Our previously hypothesized mechanism for the pathway of plasminogen (Pg) activation by streptokinase (SK) was tested by the use of full time course kinetics. Three discontinuous chromogenic substrate initial rate assays were developed with different quenching conditions that enabled quantitation of the time courses of Pg depletion, plasmin (Pm) formation, transient formation of the conformationally activated SK·Pg* catalytic complex intermediate, formation of the SK·Pm catalytic complex, and the free concentrations of Pg, Pm, and SK. Analysis of full time courses of Pg activation by five concentrations of SK along with activity-based titrations of SK·Pg* and SK·Pm formation yielded rate and dissociation constants within 2-fold of those determined previously by continuous measurement of parabolic chromogenic substrate hydrolysis and fluorescence-based equilibrium binding. The results obtained with orthogonal assays provide independent support for a mechanism in which the conformationally activated SK·Pg* complex catalyzes an initial cycle of Pg proteolytic conversion to Pm that acts as a trigger. Higher affinity binding of the formed Pm to SK outcompetes Pg binding, terminating the trigger cycle and initiating the bullet catalytic cycle by the SK·Pm complex that converts the residual Pg into Pm. The new assays can be adapted to quantitate SK-Pg activation in the context of SK- or Pg-directed inhibitors, effectors, and SK allelic variants. To support this, we show for the first time with an assay specific for SK·Pg* that fibrinogen forms a ternary SK·Pg*·fibrinogen complex, which assembles with 200-fold enhanced SK·Pg* affinity, signaled by a perturbation of the SK·Pg* active site.
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Affiliation(s)
- Miranda Nolan
- From the Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2561
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12
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Engineering streptokinase for generation of active site-labeled plasminogen analogs. Anal Biochem 2011; 415:105-15. [PMID: 21570944 DOI: 10.1016/j.ab.2011.04.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 04/07/2011] [Accepted: 04/15/2011] [Indexed: 01/18/2023]
Abstract
We previously demonstrated that streptokinase (SK) can be used to generate active site-labeled fluorescent analogs of plasminogen (Pg) by virtue of its nonproteolytic activation of the zymogen. The method is versatile and allows stoichiometric and active site-specific incorporation of any one of many molecular probes. The limitation of the labeling approach is that it is both time-consuming and low yield. Here we demonstrate an improved method for the preparation of labeled Pg analogs by the use of an engineered SK mutant fusion protein with both COOH- and NH(2)-terminal His(6) tags. The NH(2)-terminal tag is followed by a tobacco etch virus proteinase cleavage site to ensure that the SK Ile(1) residue, essential for conformational activation of Pg, is preserved. The SK COOH-terminal Lys(414) residue and residues Arg253-Leu260 in the SK β-domain were deleted to prevent cleavage by plasmin (Pm) and to disable Pg substrate binding to the SK·Pg(∗)/Pm catalytic complexes, respectively. Near elimination of Pm generation with the SKΔ(R253-L260)ΔK414-His(6) mutant increased the yield of labeled Pg 2.6-fold and reduced the time required more than 2-fold. The versatility of the labeling method was extended to the application of Pg labeled with a near-infrared probe to quantitate Pg receptors on immune cells by flow cytometry.
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13
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The role of streptococcal plasmin(ogen) binding in infective endocarditis. Eur J Clin Microbiol Infect Dis 2010; 30:127-9. [PMID: 20835741 DOI: 10.1007/s10096-010-1053-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Accepted: 08/20/2010] [Indexed: 10/19/2022]
Abstract
The ability of viridans group streptococci (VGS) to bind human plasminogen and its subsequent activation into plasmin may contribute to the pathogenesis of streptococcal endocarditis. The increased proteolytic activity acquired through cell-bound plasmin may lead to a decreased stability of the streptococcal vegetation and possible embolisation. Twenty-two infective endocarditis isolates and 16 non-infective endocarditis isolates were screened for their ability to bind plasminogen through the quantification of its active form plasmin, using the colorimetric substrate D-Val-Leu-Lys p-nitroanilide. The species of the VGS assessed expressed a universal capability to bind human plasminogen, although they did so with differing affinities and independently of the site of isolation.
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The fibrinolytic mechanism of defibrotide: effect of defibrotide on plasmin activity. Blood Coagul Fibrinolysis 2010; 20:627-34. [PMID: 19809307 DOI: 10.1097/mbc.0b013e32832da1e3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fibrinolytic activity has been shown to be reduced in many vascular diseases, including hepatic veno-occlusive disease after stem cell transplantation, a microangiopathy characterized by sinusoidal endothelial cell injury. Defibrotide is a polydisperse oligonucleotide with antithrombotic, profibrinolytic, anti-ischemic, and antiadhesive properties. Numerous clinical studies have shown promising activity of defibrotide in the treatment and prevention of veno-occlusive disease, with minimal toxicity. In corollary laboratory studies, defibrotide has been shown to decrease plasminogen activator inhibitor-1, increase tissue plasminogen activator levels, and increase overall plasma fibrinolytic activity in patients. Plasmin, a potent and nonspecific serine protease, plays a pivotal role in fibrinolysis by virtue of its ability to effectively degrade fibrin clots. In this study, defibrotide increases the activity of plasmin in hydrolyzing its substrate in a dose-dependent and length-dependent manner. Similar concentration-dependent effects of defibrotide were observed when plasmin was generated by tissue plasminogen activator or urokinase activation of plasminogen. In contrast, defibrotide had no direct effect on the activation of plasminogen to plasmin. Defibrotide was also able to enhance the activity of plasmin in degrading fibrin clot formed from fibrinogen, plasminogen, and thrombin. This effect was also concentration-dependent and directly correlated with the enzymatic activity of plasmin. This study therefore demonstrates that defibrotide is capable of enhancing the activity of plasmin and so contributes to its fibrinolytic activity. Taken together, these results support the effect of defibrotide in restoring the fibrinolytic vascular phenotype, in microangiopathic conditions such as veno-occlusive disease.
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15
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Wiles KG, Panizzi P, Kroh HK, Bock PE. Skizzle is a novel plasminogen- and plasmin-binding protein from Streptococcus agalactiae that targets proteins of human fibrinolysis to promote plasmin generation. J Biol Chem 2010; 285:21153-64. [PMID: 20435890 DOI: 10.1074/jbc.m110.107730] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Skizzle (SkzL), secreted by Streptococcus agalactiae, has moderate sequence identity to streptokinase and staphylokinase, bacterial activators of human plasminogen (Pg). SkzL binds [Glu]Pg with low affinity (K(D) 3-16 mum) and [Lys]Pg and plasmin (Pm) with indistinguishable high affinity (K(D) 80 and 50 nm, respectively). Binding of SkzL to Pg and Pm is completely lysine-binding site-dependent, as shown by the effect of the lysine analog, 6-aminohexanoic acid. Deletion of the COOH-terminal SkzL Lys(415) residue reduces affinity for [Lys]Pg and active site-blocked Pm 30-fold, implicating Lys(415) in a lysine-binding site interaction with a Pg/Pm kringle. SkzL binding to active site fluorescein-labeled Pg/Pm analogs demonstrates distinct high and low affinity interactions. High affinity binding is mediated by Lys(415), whereas the source of low affinity binding is unknown. SkzL enhances the activation of [Glu]Pg by urokinase (uPA) approximately 20-fold, to a maximum rate indistinguishable from that for [Lys]Pg and [Glu]Pg activation in the presence of 6-aminohexanoic acid. SkzL binds preferentially to the partially extended beta-conformation of [Glu]Pg, which is in unfavorable equilibrium with the compact alpha-conformation, thereby converting [Glu]Pg to the fully extended gamma-conformation and accelerating the rate of its activation by uPA. SkzL enhances [Lys]Pg and [Glu]Pg activation by single-chain tissue-type Pg activator, approximately 42- and approximately 650-fold, respectively. SkzL increases the rate of plasma clot lysis by uPA and single-chain tissue-type Pg activator approximately 2-fold, confirming its cofactor activity in a physiological model system. The results suggest a role for SkzL in S. agalactiae pathogenesis through fibrinolytic enhancement.
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Affiliation(s)
- Karen G Wiles
- Department of Pathology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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16
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Tharp AC, Laha M, Panizzi P, Thompson MW, Fuentes-Prior P, Bock PE. Plasminogen substrate recognition by the streptokinase-plasminogen catalytic complex is facilitated by Arg253, Lys256, and Lys257 in the streptokinase beta-domain and kringle 5 of the substrate. J Biol Chem 2009; 284:19511-21. [PMID: 19473980 PMCID: PMC2740577 DOI: 10.1074/jbc.m109.005512] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 05/19/2009] [Indexed: 11/06/2022] Open
Abstract
Streptokinase (SK) conformationally activates the central zymogen of the fibrinolytic system, plasminogen (Pg). The SK.Pg* catalytic complex binds Pg as a specific substrate and cleaves it into plasmin (Pm), which binds SK to form the SK.Pm complex that propagates Pm generation. Catalytic complex formation is dependent on lysine-binding site (LBS) interactions between a Pg/Pm kringle and the SK COOH-terminal Lys(414). Pg substrate recognition is also LBS-dependent, but the kringle and SK structural element(s) responsible have not been identified. SK mutants lacking Lys(414) with Ala substitutions of charged residues in the SK beta-domain 250-loop were evaluated in kinetic studies that resolved conformational and proteolytic Pg activation. Activation of [Lys]Pg and mini-Pg (containing only kringle 5 of Pg) by SK with Ala substitutions of Arg(253), Lys(256), and Lys(257) showed decreases in the bimolecular rate constant for Pm generation, with nearly total inhibition for the SK Lys(256)/Lys(257) double mutant. Binding of bovine Pg (BPg) to the SK.Pm complex containing fluorescently labeled Pm demonstrated LBS-dependent assembly of a SK.labeled Pm.BPg ternary complex, whereas BPg did not bind to the complex containing the SK Lys(256)/Lys(257) mutant. BPg was activated by SK.Pm with a K(m) indistinguishable from the K(D) for BPg binding to form the ternary complex, whereas the SK Lys(256)/Lys(257) mutant did not support BPg activation. We conclude that SK residues Arg(253), Lys(256), and Lys(257) mediate Pg substrate recognition through kringle 5 of the [Lys]Pg and mini-Pg substrates. A molecular model of the SK.kringle 5 complex identifies the putative interactions involved in LBS-dependent Pg substrate recognition.
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Affiliation(s)
- Anthony C. Tharp
- From the Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Malabika Laha
- From the Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Peter Panizzi
- From the Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Michael W. Thompson
- From the Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Pablo Fuentes-Prior
- the Institut de Recerca, Hospital de la Santa Creu i Sant Pau, 08025 Barcelona, Spain
| | - Paul E. Bock
- From the Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
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17
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Jensen JK, Dolmer K, Gettins PGW. Specificity of binding of the low density lipoprotein receptor-related protein to different conformational states of the clade E serpins plasminogen activator inhibitor-1 and proteinase nexin-1. J Biol Chem 2009; 284:17989-97. [PMID: 19439404 DOI: 10.1074/jbc.m109.009530] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The low density lipoprotein receptor-related protein (LRP) is the principal clearance receptor for serpins and serpin-proteinase complexes. The ligand binding regions of LRP consist of clusters of cysteine-rich approximately 40-residue complement-like repeats (CR), with cluster II being the principal ligand-binding region. To better understand the specificity of binding at different sites within the cluster and the ability of LRP to discriminate in vivo between uncomplexed and proteinase-complexed serpins, we have systematically examined the affinities of plasminogen activator inhibitor-1 (PAI-1) and proteinase nexin-1 (PN-1) in their native, cleaved, and proteinase-complexed states to (CR)(2) and (CR)(3) fragments of LRP cluster II. A consistent blue shift of the CR domain tryptophan fluorescence suggested a common mode of serpin binding, involving lysines on the serpin engaging the acidic region around the calcium binding site of the CR domain. High affinity binding of non-proteinase-complexed PAI-1 and PN-1 occurred to all fragments containing three CR domains (3-59 nm) and most that contain only two CR domains, although binding energies to different (CR)(3) fragments differed by up to 18% for PAI-1 and 9% for PN-1. No detectable difference in affinity was seen between native and cleaved serpin. However, the presence of proteinase in complex with the serpin enhanced affinity modestly and presumably nonspecifically. This may be sufficient to give preferential binding of such complexes in vivo at the relevant physiological concentrations.
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Affiliation(s)
- Jan K Jensen
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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18
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Von Willebrand factor-binding protein is a hysteretic conformational activator of prothrombin. Proc Natl Acad Sci U S A 2009; 106:7786-91. [PMID: 19416890 DOI: 10.1073/pnas.0811750106] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Von Willebrand factor-binding protein (VWbp), secreted by Staphylococcus aureus, displays secondary structural homology to the 3-helix bundle, D1 and D2 domains of staphylocoagulase (SC), a potent conformational activator of the blood coagulation zymogen, prothrombin (ProT). In contrast to the classical proteolytic activation mechanism of trypsinogen-like serine proteinase zymogens, insertion of the first 2 residues of SC into the NH(2)-terminal binding cleft on ProT (molecular sexuality) induces rapid conformational activation of the catalytic site. Based on plasma-clotting assays, the target zymogen for VWbp may be ProT, but this has not been verified, and the mechanism of ProT activation is unknown. We demonstrate that VWbp activates ProT conformationally in a mechanism requiring its Val(1)-Val(2) residues. By contrast to SC, full time-course kinetic studies of ProT activation by VWbp demonstrate that it activates ProT by a substrate-dependent, hysteretic kinetic mechanism. VWbp binds weakly to ProT (K(D) 2.5 microM) to form an inactive complex, which is activated through a slow conformational change by tripeptide chromogenic substrates and its specific physiological substrate, identified here as fibrinogen (Fbg). This mechanism increases the specificity of ProT activation by delaying it in a slow reversible process, with full activation requiring binding of Fbg through an exosite expressed on the activated ProT*.VWbp complex. The results suggest that this unique mechanism regulates pathological fibrin (Fbn) deposition to VWF-rich areas during S. aureus endocarditis.
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Verhamme IM, Bock PE. Rapid-reaction kinetic characterization of the pathway of streptokinase-plasmin catalytic complex formation. J Biol Chem 2008; 283:26137-47. [PMID: 18658146 DOI: 10.1074/jbc.m804038200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Binding of the fibrinolytic proteinase plasmin (Pm) to streptokinase (SK) in a tight stoichiometric complex transforms Pm into a potent proteolytic activator of plasminogen. SK binding to the catalytic domain of Pm, with a dissociation constant of 12 pm, is assisted by SK Lys(414) binding to a Pm kringle, which accounts for a 11-20-fold affinity decrease when Pm lysine binding sites are blocked by 6-aminohexanoic acid (6-AHA) or benzamidine. The pathway of SK.Pm catalytic complex formation was characterized by stopped-flow kinetics of SK and the Lys(414) deletion mutant (SKDeltaK414) binding to Pm labeled at the active site with 5-fluorescein ([5F]FFR-Pm) and the reverse reactions by competitive displacement of [5F]FFR-Pm with active site-blocked Pm. The rate constants for the biexponential fluorescence quenching caused by SK and SKDeltaK414 binding to [5F]FFR-Pm were saturable as a function of SK concentration, reporting encounter complex affinities of 62-110 nm in the absence of lysine analogs and 4900-6500 and 1430-2200 nm in the presence of 6-AHA and benzamidine, respectively. The encounter complex with SKDeltaK414 was approximately 10-fold weaker in the absence of lysine analogs but indistinguishable from that of native SK in the presence of 6-AHA and benzamidine. The studies delineate for the first time the sequence of molecular events in the formation of the SK.Pm catalytic complex and its regulation by kringle ligands. Analysis of the forward and reverse reactions supports a binding mechanism in which SK Lys(414) binding to a Pm kringle accompanies near-diffusion-limited encounter complex formation followed by two slower, tightening conformational changes.
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Affiliation(s)
- Ingrid M Verhamme
- Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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20
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Jaisson S, Sartelet H, Perreau C, Blanchevoye C, Garnotel R, Gillery P. Involvement of lysine 1047 in type I collagen-mediated activation of polymorphonuclear neutrophils. FEBS J 2008; 275:3226-35. [DOI: 10.1111/j.1742-4658.2008.06474.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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21
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Abstract
Bacterial pathogens have frequently evolved and maintained the capacity to engage and/or activate hemostatic system components of their vertebrate hosts. Recent studies of mice with selected alterations in host plasminogen and other hemostatic factors have begun to reveal a seminal role of bacterial plasminogen activators and fibrin clearance in microbial pathogenesis. Bacterial pathogens appear to exploit host plasmin-mediated proteolysis to both support microbial dissemination and evade innate immune surveillance systems. The contribution of bacterial plasminogen activation to the evasion of the inflammatory response is particularly conspicuous with the plague agent, Yersinia pestis. Infection of control mice with wild-type Y. pestis leads to the formation of widespread foci containing massive numbers of free bacteria with little inflammatory cell infiltrate, whereas the loss of either the bacterial plasminogen activator, Pla, or the elimination of host plasminogen results in the accumulation of robust inflammatory cell infiltrates at sites of infection and greatly improved survival. Interestingly, fibrin(ogen) deficiency undermines the local inflammatory response observed with Pla-deficient Y. pestis and effectively eliminates the survival benefits posed by the elimination of either host plasminogen or bacterial Pla. These studies, and complementary studies with other human pathogens, illustrate that plasminogen and fibrinogen are extremely effective modifiers of the inflammatory response in vivo and critical determinants of bacterial virulence and host defense. Detailed studies of the inflammatory response in mice with genetically-imposed modifications in coagulation and fibrinolytic factors underscore the regulatory crosstalk between the hemostatic and immune systems.
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Affiliation(s)
- J L Degen
- Division of Developmental Biology, Children's Hospital Research Foundation and the University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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