SmSP2: A serine protease secreted by the blood fluke pathogen Schistosoma mansoni with anti-hemostatic properties.

BackgroundSerine proteases are important virulence factors for many pathogens. Recently, we discovered a group of trypsin-like serine proteases with domain organization unique to flatworm parasites and containing a thrombospondin type 1 repeat (TSR-1). These proteases are recognized as antigens during host infection and may prove useful as anthelminthic vaccines, however their molecular characteristics are under-studied. Here, we characterize the structural and proteolytic attributes of serine protease 2 (SmSP2) from Schistosoma mansoni, one of the major species responsible for the tropical infectious disease, schistosomiasis.Methodology/principal findingsSmSP2 comprises three domains: a histidine stretch, TSR-1 and a serine protease domain. The cleavage specificity of recombinant SmSP2 was determined using positional scanning and multiplex combinatorial libraries and the determinants of specificity were identified with 3D homology models, demonstrating a trypsin-like endopeptidase mode of action. SmSP2 displayed restricted proteolysis on protein substrates. It activated tissue plasminogen activator and plasminogen as key components of the fibrinolytic system, and released the vasoregulatory peptide, kinin, from kininogen. SmSP2 was detected in the surface tegument, esophageal glands and reproductive organs of the adult parasite by immunofluorescence microscopy, and in the excretory/secretory products by immunoblotting.Conclusions/significanceThe data suggest that SmSP2 is secreted, functions at the host-parasite interface and contributes to the survival of the parasite by manipulating host vasodilatation and fibrinolysis. SmSP2 may be, therefore, a potential target for anti-schistosomal therapy

Molecular Electroporation and the Transduction of Oligoarginines

Certain short polycations, such as TAT and polyarginine, rapidly pass through the plasma membranes of mammalian cells by an unknown mechanism called transduction as well as by endocytosis and macropinocytosis. These cell-penetrating peptides (CPPs) promise to be medically useful when fused to biologically active peptides. I offer a simple model in which one or more CPPs and the phosphatidylserines of the inner leaflet form a kind of capacitor with a voltage in excess of 180 mV, high enough to create a molecular electropore. The model is consistent with an empirical upper limit on the cargo peptide of 40--60 amino acids and with experimental data on how the transduction of a polyarginine-fluorophore into mouse C2C12 myoblasts depends on the number of arginines in the CPP and on the CPP concentration. The model makes three testable predictions.Comment: 15 pages, 5 figure

Change in Magnetic Anisotropy at the Surface and in the Bulk of FINEMET Induced by Swift Heavy Ion Irradiation

57 Fe transmission and conversion electron Mössbauer spectroscopy as well as XRD were used to study the effect of swift heavy ion irradiation on stress-annealed FINEMET samples with a composition of Fe73.5 Si13.5 Nb3 B9 Cu1. The XRD of the samples indicated changes neither in the crystal structure nor in the texture of irradiated ribbons as compared to those of non-irradiated ones. However, changes in the magnetic anisotropy both in the bulk as well as at the surface of the FINEMET alloy ribbons irradiated by 160 MeV132 Xe ions with a fluence of 1013 ion cm−2 were revealed via the decrease in relative areas of the second and fifth lines of the magnetic sextets in the corresponding Mössbauer spectra. The irradiation-induced change in the magnetic anisotropy in the bulk was found to be similar or somewhat higher than that at the surface. The results are discussed in terms of the defects produced by irradiation and corresponding changes in the orientation of spins depending on the direction of the stress generated around these defects. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.CZ-11/2007, MEB040806; Ministry of Education and Science of the Russian Federation, Minobrnauka: FEUZ-2020-0060; Hungarian Scientific Research Fund, OTKA: K100424, K115784, K115913, K43687, K68135; Joint Institute for Nuclear Research, JINR; Univerzita Palackého v Olomouci: CZ.02.1.01/0.0/0.0/17_049/0008408, IGA_PrF_2022_003, IGA_PrF_2022_013; Ural Federal University, UrFU: 04-5-1131-2017/2021; Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIHFunding: The research was supported by grants from the Hungarian National Research, Development and Innovation Office (OTKA projects No K43687, K68135, K100424, K115913, K115784) and by the Czech-Hungarian Intergovernmental Fund, Grant No. CZ-11/2007 (MEB040806). M.I.O. was supported by the Ministry of Science and Higher Education of the Russian Federation, project No. FEUZ-2020-0060. Additionally, M.I.O. was supported in part by the Ural Federal University project within the Priority-2030 Program, funded from the Ministry of Science and Higher Education of the Russian Federation. This work was also supported by the project “Swift heavy ions in research of iron-bearing nanomaterials”, No. of theme 04-5-1131-2017/2021, solved in cooperation with the Czech Republic and the JINR (3 + 3 projects), and also by internal IGA grant of Palacký University (IGA_PrF_2022_003). The authors from Palacký University Olomouc want to thank the facilitators of project CZ.02.1.01/0.0/0.0/17_049/0008408 of the Ministry of Education, Youth & Sports of the Czech Republic for their support as well.Acknowledgments: We are grateful to Z. Klencsár (Centre for Energy Research, Budapest), M. Miglierini (Technical University, Bratislava), I. Dézsi (Wigner Research Centre for Physics, Budapest), S. Kubuki, and K. Nomura (Tokyo Metropolitan University, Tokyo) for their participation in discussions, and L. Krupa (Czech Technical University in Prague, Czech Republic and Joint Institute for Nuclear Research, Dubna) for his help with the organization of project cooperation. The support by grants from the Hungarian National Research, Development and Innovation Office and by the Czech-Hungarian Intergovernmental Fund, Grant No. CZ-11/2007 (MEB040806) are acknowledged. M.I.O. is grateful for support from the Ministry of Science and Higher Education of the Russian Federation and from the Ural Federal University project within the Priority-2030 Program. This work was also carried out within the Agreement of Cooperation between the Ural Federal University (Ekaterinburg) and the Eötvös Loránd University (Budapest) and within the Memorandum of Understanding between the Ural Federal University (Ekaterinburg) and the Palacký University (Olomouc). Authors acknowledge the support of the project “Swift heavy ions in research of iron-bearing nanomaterials”, No. of theme 04-5-1131-2017/2021, solved in cooperation with the Czech Republic and the JINR (3 + 3 projects). Authors from Palacký University Olomouc appreciate the internal IGA grant of Palacký University (IGA_PrF_2022_013) and thank the facilitators of the project CZ.02.1.01/0.0/0.0/17_049/0008408 of the Ministry of Education, Youth & Sports of the Czech Republic as well

Regioselective Palmitoylation of 9-(2,3-Dihydroxy- propyl)adenine Catalyzed by a Glycopolymer-enzyme Conjugate

The enzymatic regioselective monopalmitoylation of racemic 9-(2,3-dihydroxypropyl)- adenine (DHPA), an approved antiviral agent, has been performed by an immobilized form of Candida antarctica B lipase (CAL-B) using a 4:1 DMF/hexane mixture as the reaction medium. To improve the chemical yield of the desired monopalmitoylation reaction, solid-phase chemical modifications of the lipase were evaluated. The reaction yield was successfully increased obtaining 100% product after a second treatment of the product solution with fresh immobilised chemically glycosylated-CAL-B.The authors thank the Ramon Areces Foundation for financial support and the Academy of Sciences of the Czech Republic (project No. M200551203). The authors are grateful to the team of Jan Balzarini at the Rega Institute for Medical Research KU Leuven (Belgium) for the screening of biological activity and thank Abian from the Institute for Biocomputation and Physics (BIFI) for technical support in the CD and fluorescent spectra as well as Ramiro Martinez from Novozymes for the generous gift of lipases. We thank Lydia Burke (Technical Dublin University, Irland) for the proof-reading of the articleWe acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

Trypsin- and Chymotrypsin-Like Serine Proteases in Schistosoma mansoni - 'The Undiscovered Country'

Background:Blood flukes (Schistosoma spp.) are parasites that can survive for years or decades in the vasculature of permissive mammalian hosts, including humans. Proteolytic enzymes (proteases) are crucial for successful parasitism, including aspects of

Trypsin- and Chymotrypsin-Like Serine Proteases in Schistosoma mansoni - 'The Undiscovered Country'

Background:Blood flukes (Schistosoma spp.) are parasites that can survive for years or decades in the vasculature of permissive mammalian hosts, including humans. Proteolytic enzymes (proteases) are crucial for successful parasitism, including aspects of

SmSP2: A serine protease secreted by the blood fluke pathogen Schistosoma mansoni with anti-hemostatic properties.

BACKGROUND:Serine proteases are important virulence factors for many pathogens. Recently, we discovered a group of trypsin-like serine proteases with domain organization unique to flatworm parasites and containing a thrombospondin type 1 repeat (TSR-1). These proteases are recognized as antigens during host infection and may prove useful as anthelminthic vaccines, however their molecular characteristics are under-studied. Here, we characterize the structural and proteolytic attributes of serine protease 2 (SmSP2) from Schistosoma mansoni, one of the major species responsible for the tropical infectious disease, schistosomiasis. METHODOLOGY/PRINCIPAL FINDINGS:SmSP2 comprises three domains: a histidine stretch, TSR-1 and a serine protease domain. The cleavage specificity of recombinant SmSP2 was determined using positional scanning and multiplex combinatorial libraries and the determinants of specificity were identified with 3D homology models, demonstrating a trypsin-like endopeptidase mode of action. SmSP2 displayed restricted proteolysis on protein substrates. It activated tissue plasminogen activator and plasminogen as key components of the fibrinolytic system, and released the vasoregulatory peptide, kinin, from kininogen. SmSP2 was detected in the surface tegument, esophageal glands and reproductive organs of the adult parasite by immunofluorescence microscopy, and in the excretory/secretory products by immunoblotting. CONCLUSIONS/SIGNIFICANCE:The data suggest that SmSP2 is secreted, functions at the host-parasite interface and contributes to the survival of the parasite by manipulating host vasodilatation and fibrinolysis. SmSP2 may be, therefore, a potential target for anti-schistosomal therapy