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Singh S, Chaudhary C, Bharsakale RD, Gazal S, Verma L, Tarannum Z, Behere GT, Giri J, Germain H, Ghosh DK, Sharma AK, Chauhan H. PRpnp, a novel dual activity PNP family protein improves plant vigour and confers multiple stress tolerance in Citrus aurantifolia. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:726-741. [PMID: 36593511 PMCID: PMC10037160 DOI: 10.1111/pbi.13989] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/04/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
Under field conditions, plants are often simultaneously exposed to several abiotic and biotic stresses resulting in significant reductions in growth and yield; thus, developing a multi-stress tolerant variety is imperative. Previously, we reported the neofunctionalization of a novel PNP family protein, Putranjiva roxburghii purine nucleoside phosphorylase (PRpnp) to trypsin inhibitor to cater to the needs of plant defence. However, to date, no study has revealed the potential role and mechanism of either member of this protein group in plant defence. Here, we overexpressed PRpnp in Citrus aurantifolia which showed nuclear-cytoplasmic localization, where it functions in maintaining the intracellular purine reservoir. Overexpression of PRpnp significantly enhanced tolerance to salt, oxidative stress, alkaline pH, drought and two pests, Papilio demoleus and Scirtothrips citri in transgenic plants. Global gene expression studies revealed that PRpnp overexpression up-regulated differentially expressed genes (DEGs) related to ABA- and JA-biosynthesis and signalling, plant defence, growth and development. LC-MS/MS analysis validated higher endogenous ABA and JA accumulation in transgenic plants. Taken together, our results suggest that PRpnp functions by enhancing the endogenous ABA and JA, which interact synergistically and it also inhibits trypsin proteases in the insect gut. Also, like other purine salvage genes, PRpnp also regulates CK metabolism and increases the levels of CK-free bases in transgenic Mexican lime. We also suggest that PRpnp can be used as a potential candidate to develop new varieties with improved plant vigour and enhanced multiple stress resistance.
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Affiliation(s)
- Sweta Singh
- Department of Biosciences and BioengineeringIndian Institute of Technology RoorkeeRoorkeeIndia
| | - Chanderkant Chaudhary
- Department of Biosciences and BioengineeringIndian Institute of Technology RoorkeeRoorkeeIndia
| | | | - Snehi Gazal
- Department of Chemistry, Biochemistry and PhysicsUniversité du Québec à Trois‐RivièresTrois‐RivièresQuebecCanada
| | - Lokesh Verma
- National Institute of Plant Genome ResearchNew DelhiIndia
| | - Zeba Tarannum
- Department of Biosciences and BioengineeringIndian Institute of Technology RoorkeeRoorkeeIndia
| | | | - Jitender Giri
- National Institute of Plant Genome ResearchNew DelhiIndia
| | - Hugo Germain
- Department of Chemistry, Biochemistry and PhysicsUniversité du Québec à Trois‐RivièresTrois‐RivièresQuebecCanada
| | | | - Ashwani K. Sharma
- Department of Biosciences and BioengineeringIndian Institute of Technology RoorkeeRoorkeeIndia
| | - Harsh Chauhan
- Department of Biosciences and BioengineeringIndian Institute of Technology RoorkeeRoorkeeIndia
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Molecular Characterization of Kunitz-Type Protease Inhibitors from Blister Beetles (Coleoptera, Meloidae). Biomolecules 2022; 12:biom12070988. [PMID: 35883544 PMCID: PMC9312475 DOI: 10.3390/biom12070988] [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: 05/24/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 02/01/2023] Open
Abstract
Protease inhibitors are widely studied since the unrestricted activity of proteases can cause extensive organ lesions. In particular, elastase activity is involved in the pathophysiology of acute lung injury, for example during SARS-CoV-2 infection, while serine proteases and thrombin-like proteases are involved in the development and/or pathology of the nervous system. Natural protease inhibitors have the advantage to be reversible and with few side effects and thus are increasingly considered as new drugs. Kunitz-type protease inhibitors (KTPIs), reported in the venom of various organisms, such as wasps, spiders, scorpions, and snakes, have been studied for their potent anticoagulant activity and widespread protease inhibitor activity. Putative KTPI anticoagulants have been identified in transcriptomic resources obtained for two blister beetle species, Lydus trimaculatus and Mylabris variabilis. The KTPIs of L. trimaculatus and M. variabilis were characterized by combined transcriptomic and bioinformatics methodologies. The full-length mRNA sequences were divided on the base of the sequence of the active sites of the putative proteins. In silico protein structure analyses of each group of translational products show the biochemical features of the active sites and the potential protease targets. Validation of these genes is the first step for considering these molecules as new drugs for use in medicine.
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Kao WT, Chang CT, Lin KW. Antioxidant and trypsin inhibition activity of dioscorin influenced by yam cultivars and eluent pH. Int J Food Sci Technol 2012. [DOI: 10.1111/j.1365-2621.2012.02984.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sun M, Mu T, Zhang M, Arogundade LA. Nutritional assessment and effects of heat processing on digestibility of Chinese sweet potato protein. J Food Compost Anal 2012. [DOI: 10.1016/j.jfca.2012.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Senthilkumar R, Yeh KW. Multiple biological functions of sporamin related to stress tolerance in sweet potato (Ipomoea batatas Lam). Biotechnol Adv 2012; 30:1309-17. [PMID: 22306516 DOI: 10.1016/j.biotechadv.2012.01.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 12/22/2011] [Accepted: 01/20/2012] [Indexed: 12/27/2022]
Abstract
The initial investigation of the nature of the proteins in the tuber of sweet potato (Ipomoea batatas Lam.) revealed a globulin-designated "ipomoein," which was reported by Jones and Gersdorff, (1931). Later, "ipomoein" was renamed "sporamin" and was found to be a major storage protein that accounted for over 80% of the total protein in the tuberous root. To date, sporamin has been studied by a series of biochemical and molecular approaches. The first purification of sporamin into two major fractions, A and B, was successfully completed in 1985. Several characteristics of the protein, such as the diversification of the nucleotide sequences in the gene family, the protein structure, the biological functions of storage, defense, inhibitory activity and ROS scavenging, were identified. In the past decade, sporamin was classified as a Kunitz-type trypsin inhibitor, and its insect-resistance capability has been examined in transgenic tobacco and cauliflower plants, indicating the multiple functions of this protein has evolved to facilitate the growth and development of sweet potato. Sporamin is constitutively expressed in the tuberous root and is not normally expressed in the stem or leaves. However, this protein is expressed systemically in response to wounding and other abiotic stresses. These dual expression patterns at the transcriptional level revealed that the complex regulatory mechanism of sporamin was modulated by environmental stresses. The versatile functions of sporamin make this storage protein a good research model to study molecular evolution, regulatory mechanisms and physiological functions in plants. This review summarizes and discusses recent approaches and future perspectives in agricultural biotechnology.
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Hung CH, Chen PJ, Wang HL. Evidence that highly conserved residues of Delonix regia trypsin inhibitor are important for activity. BIOCHEMISTRY (MOSCOW) 2011; 75:1388-92. [PMID: 21314607 DOI: 10.1134/s0006297910110118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Delonix regia trypsin inhibitor (DrTI) consists of a single-polypeptide chain with a molecular mass of 22 kDa and containing two disulfide bonds (Cys44-Cys89 and Cys139-Cys149). Sequence comparison with other plant trypsin inhibitors of the Kunitz family reveals that DrTI contains a negatively charged residue (Glu68) at the reactive site rather than the conserved Arg or Lys found in other Kunitz-type trypsin inhibitors. Site-directed mutagenesis yielded five mutants containing substitutions at the reactive site and at one of the disulfide bonds. Assay of the recombinant proteins showed mutant Glu68Leu and Glu68Lys to have only 4-5% of the wild-type activity. These provide evidence that the Glu68 residue is the reactive site for DrTI and various other Kunitz-type trypsin inhibitors. The Cys139Gly mutant lost its inhibitory activity, whereas the Cys44Gly mutant did not, indicating that the second disulfide bond (Cys139-Cys149) is critical to DrTI inhibitory activity, while the first disulfide bond (Cys44-Cys89) is not required.
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Affiliation(s)
- Chih-Hung Hung
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Hsinchu 300, Taiwan, ROC.
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Guo Q, Mu T. Emulsifying properties of sweet potato protein: Effect of protein concentration and oil volume fraction. Food Hydrocoll 2011. [DOI: 10.1016/j.foodhyd.2010.05.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Macedo MLR, Freire MDGM, Kubo CEG, Parra JRP. Bioinsecticidal activity of Talisia esculenta reserve protein on growth and serine digestive enzymes during larval development of Anticarsia gemmatalis. Comp Biochem Physiol C Toxicol Pharmacol 2011; 153:24-33. [PMID: 20692365 DOI: 10.1016/j.cbpc.2010.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 08/01/2010] [Accepted: 08/02/2010] [Indexed: 10/19/2022]
Abstract
Plants synthesize a variety of molecules to defend themselves against an attack by insects. Talisin is a reserve protein from Talisia esculenta seeds, the first to be characterized from the family Sapindaceae. In this study, the insecticidal activity of Talisin was tested by incorporating the reserve protein into an artificial diet fed to the velvetbean caterpillar Anticarsia gemmatalis, the major pest of soybean crops in Brazil. At 1.5% (w/w) of the dietary protein, Talisin affected larval growth, pupal weight, development and mortality, adult fertility and longevity, and produced malformations in pupae and adult insects. Talisin inhibited the trypsin-like activity of larval midgut homogenates. The trypsin activity in Talisin-fed larvae was sensitive to Talisin, indicating that no novel protease-resistant to Talisin was induced in Talisin-fed larvae. Affinity chromatography showed that Talisin bound to midgut proteinases of the insect A. gemmatalis, but was resistant to enzymatic digestion by these larval proteinases. The transformation of genes coding for this reserve protein could be useful for developing insect resistant crops.
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Affiliation(s)
- Maria Lígia R Macedo
- Laboratório de Purificação de Proteínas e suas Funções Biológicas, Departamento de Tecnologia de Alimentos, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil.
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Senthilkumar R, Cheng CP, Yeh KW. Genetically pyramiding protease-inhibitor genes for dual broad-spectrum resistance against insect and phytopathogens in transgenic tobacco. PLANT BIOTECHNOLOGY JOURNAL 2010; 8:65-75. [PMID: 20055959 DOI: 10.1111/j.1467-7652.2009.00466.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Protease inhibitors provide a promising means of engineering plant resistance against attack by insects and pathogens. Sporamin (trypsin inhibitor) from sweet potato and CeCPI (phytocystatin) from taro were stacked in a binary vector, using pMSPOA (a modified sporamin promoter) to drive both genes. Transgenic tobacco lines of T0 and T1 generation with varied inhibitory activity against trypsin and papain showed resistance to both insects and phytopathogens. Larvae of Helicoverpa armigera that ingested tobacco leaves either died or showed delayed growth and development relative to control larvae. Transgenic tobacco-overexpressing the stacked genes also exhibited strong resistance against bacterial soft rot disease caused by Erwinia carotovora and damping-off disease caused by Pythium aphanidermatum. Thus, stacking protease-inhibitor genes, driven by the wound and pathogen responsive pMSPOA promoter, is an effective strategy for engineering crops to resistance against insects and phytopathogens.
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Lin CH, Lu CT, Lin HT, Pan TM. Safety assessment and detection method of genetically modified Chinese Kale (Brassica oleracea cv. alboglabra ). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:1876-1881. [PMID: 19216530 DOI: 10.1021/jf8034644] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Sporamins are tuberous storage proteins and account for 80% of soluble protein in sweet potato tubers with trypsin-inhibitory activity. The expression of sporamin protein in transgenic Chinese kale (line BoA 3-1) conferred insecticidal activity toward corn earworm [ Helicoverpa armigera (Hubner)] in a previous report. In this study, we present a preliminary safety assessment of transgenic Chinese kale BoA 3-1. Bioinformatic and simulated gastric fluid (SGF) analyses were performed to evaluate the allergenicity of sporamin protein. The substantial equivalence between transgenic Chinese kale and its wild-type host has been demonstrated by the comparison of important constituents. A reliable real-time polymerase chain reaction (PCR) detection method was also developed to control sample quality. Despite the results of most evaluations in this study being negative, the safety of sporamin in transgenic Chinese kale BoA 3-1 was uncluded because of the allergenic risk revealed by bioinformatic analysis.
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Affiliation(s)
- Chih-Hui Lin
- Institute of Microbiology and Biochemistry, College of Life Science, National Taiwan University, Number 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
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Ku AT, Huang YS, Wang YS, Ma D, Yeh KW. IbMADS1 (Ipomoea batatas MADS-box 1 gene) is involved in tuberous root initiation in sweet potato (Ipomoea batatas). ANNALS OF BOTANY 2008; 102:57-67. [PMID: 18463111 PMCID: PMC2712425 DOI: 10.1093/aob/mcn067] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 02/13/2008] [Accepted: 03/31/2008] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS The tuberization mechanism of sweet potato (Ipomoea batatas) has long been studied using various approaches. Morphological data have revealed that the tuberizing events result from the activation of the cambium, followed by cell proliferation. However, uncertainties still remain regarding the regulators participating in this signal-transduction pathway. An attempt was made to characterize the role of one MADS-box transcription factor, which was preferentially expressed in sweet potato roots at the early tuberization stage. METHODS A differential expression level of IbMADS1 (Ipomoea batatas MADS-box 1) was detected temporally and spatially in sweet potato tissues. IbMADS1 responses to tuberization-related hormones were assessed. In order to identify the evolutionary significance, the expression pattern of IbMADS1 was surveyed in two tuber-deficient Ipomoea relatives, I. leucantha and I. trifida, and compared with sweet potato. In functional analyses, potato (Solanum tuberosum) was employed as a heterologous model. The resulting tuber morphogenesis was examined anatomically in order to address the physiological function of IbMADS1, which should act similarly in sweet potato. KEY RESULTS IbMADS1 was preferentially expressed as tuberous root development proceeded. Its expression was inducible by tuberization-related hormones, such as jasmonic acid and cytokinins. In situ hybridization data showed that IbMADS1 transcripts were specifically distributed around immature meristematic cells within the stele and lateral root primordia. Inter-species examination indicated that IbMADS1 expression was relatively active in sweet potato roots, but undetectable in tuber-deficient Ipomoea species. IbMADS1-transformed potatoes exhibited tuber morphogenesis in the fibrous roots. The partial swellings along fibrous roots were mainly due to anomalous proliferation and differentiation in the xylem. CONCLUSIONS Based on this study, it is proposed that IbMADS1 is an important integrator at the initiation of tuberization. As a result, the initiation and development of tuberous roots seems to be well regulated by a network involving a MADS-box gene in which such hormones as jasmonic acid and cytokinins may act as trigger factors.
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Affiliation(s)
- Amy Tsu Ku
- Institute of Plant Biology, National Taiwan University, 10617, Taipei, Taiwan
| | - Yi-Shiuan Huang
- Institute of Plant Biology, National Taiwan University, 10617, Taipei, Taiwan
| | - Yu-Shu Wang
- Institute of Plant Biology, National Taiwan University, 10617, Taipei, Taiwan
| | - Daifu Ma
- Institute of Sweet Potato, Xuzhou, 221121, Jiangsu, China
| | - Kai-Wun Yeh
- Institute of Plant Biology, National Taiwan University, 10617, Taipei, Taiwan
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Major IT, Constabel CP. Functional analysis of the Kunitz trypsin inhibitor family in poplar reveals biochemical diversity and multiplicity in defense against herbivores. PLANT PHYSIOLOGY 2008; 146:888-903. [PMID: 18024557 PMCID: PMC2259082 DOI: 10.1104/pp.107.106229] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 11/06/2007] [Indexed: 05/21/2023]
Abstract
We investigated the functional and biochemical variability of Kunitz trypsin inhibitor (KTI) genes of Populus trichocarpa x Populus deltoides. Phylogenetic analysis, expressed sequence tag databases, and western-blot analysis confirmed that these genes belong to a large and diverse gene family with complex expression patterns. Five wound- and herbivore-induced genes representing the diversity of the KTI gene family were selected for functional analysis and shown to produce active KTI proteins in Escherichia coli. These recombinant KTI proteins were all biochemically distinct and showed clear differences in efficacy against trypsin-, chymotrypsin-, and elastase-type proteases, suggesting functional specialization of different members of this gene family. The in vitro stability of the KTIs in the presence of reducing agents and elevated temperature also varied widely, emphasizing the biochemical differences of these proteins. Significantly, the properties of the recombinant KTI proteins were not predictable from primary amino acid sequence data. Proteases in midgut extracts of Malacosoma disstria, a lepidopteran pest of Populus, were strongly inhibited by at least two of the KTI gene products. This study suggests that the large diversity in the poplar (Populus spp.) KTI family is important for biochemical and functional specialization, which may be important in the maintenance of pest resistance in long-lived plants such as poplar.
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Affiliation(s)
- Ian T Major
- Centre for Forest Biology and Department of Biology, University of Victoria, Victoria, BC, Canada
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Brandsdal BO, Smalås AO, Aqvist J. Free energy calculations show that acidic P1 variants undergo large pKa shifts upon binding to trypsin. Proteins 2006; 64:740-8. [PMID: 16752417 DOI: 10.1002/prot.20940] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Serine proteinases and their protein inhibitors belong to one of the most comprehensively studied models of protein-protein interactions. It is well established that the narrow trypsin specificity is caused by the presence of a negatively charged aspartate at the specificity pocket. X-ray crystallography as well as association measurements revealed, surprisingly, that BPTI with glutamatic acid as the primary binding (P1) residue was able to bind to trypsin. Previous free energy calculations showed that there was a substantially unfavorable binding free energy associated with accommodation of ionized P1 Glu at the S1-site of trypsin. In this study, the binding of P1 Glu to trypsin has been systematically investigated in terms of the protonation states of P1 Glu and Asp189, the orientation of Gln192, as well as the possible presence of counterions using the linear interaction energy (LIE) approach and the free energy perturbation (FEP) method. Twenty-four conceivable binding arrangements were evaluated and quantitative agreement with experiments is obtained when the P1 Glu binds in its protonated from. The results suggest that P1 Glu is one of the variants of BPTI that inhibit trypsin strongest at low pH, contrary to the specificity profile of trypsin, suggesting a new regulation mechanism of trypsin-like enzymes.
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Affiliation(s)
- Bjørn O Brandsdal
- The Norwegian Structural Biology Centre, Department of Chemistry, University of Tromsø, Tromsø, Norway.
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Mieszczanek J, Harrison LM, Cappello M. Ancylostoma ceylanicum anticoagulant peptide-1: role of the predicted reactive site amino acid in mediating inhibition of coagulation factors Xa and VIIa. Mol Biochem Parasitol 2004; 137:151-9. [PMID: 15279961 DOI: 10.1016/j.molbiopara.2004.05.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 05/25/2004] [Accepted: 05/25/2004] [Indexed: 11/20/2022]
Abstract
Hookworm infection is a leading cause of gastrointestinal blood loss and iron deficiency anemia in developing countries. Ancylostoma hookworms secrete potent anticoagulants, which have been shown to target coagulation factors Xa and the factor VIIa/Tissue Factor complex, respectively. The goal of these experiments was to determine the mechanism of action of three recombinant hookworm anticoagulants using in vitro assays. Three hookworm coagulation inhibitors were expressed and purified, along with site directed mutants targeting each of the predicted P1 inhibitory reactive site amino acid residues. Using chromogenic assays, it has been confirmed that Ancylostoma caninum Anticoagulant Peptide 5 (AcAP5) inhibits coagulation factor Xa (fXa) by a canonical, substrate-like mechanism. In contrast, Ancylostoma ceylanicum Anticoagulant Peptide-1 (AceAP1) binds to and inhibits fXa by both active site and non-active site mediated interactions. Data from in vitro studies also demonstrates that AceAP1 inhibits the factor VIIa/Tissue complex (fVIIa/TF) and displays a distinct pattern of fXa binding. Together, these data suggest that the human hookworm A. ceylanicum has evolved a single anticoagulant that targets multiple components of the mammalian coagulation response, effectively mimicking the concerted action of the two related inhibitors from A. caninum. Despite the amino acid sequence similarity, AceAP1 appears to interact with coagulation proteases fXa and fVIIa by a novel mechanism, perhaps explaining its spectrum of inhibitory activity.
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Affiliation(s)
- Juliusz Mieszczanek
- Program in International Child Health, Department of Pediatrics, Yale School of Medicine, New Haven, CT 06520, USA
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Chu D, Bungiro RD, Ibanez M, Harrison LM, Campodonico E, Jones BF, Mieszczanek J, Kuzmic P, Cappello M. Molecular characterization of Ancylostoma ceylanicum Kunitz-type serine protease inhibitor: evidence for a role in hookworm-associated growth delay. Infect Immun 2004; 72:2214-21. [PMID: 15039345 PMCID: PMC375216 DOI: 10.1128/iai.72.4.2214-2221.2004] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hookworm infection is a major cause of iron deficiency anemia and malnutrition in developing countries. The Ancylostoma ceylanicum Kunitz-type inhibitor (AceKI) is a 7.9-kDa broad-spectrum inhibitor of trypsin, chymotrypsin, and pancreatic elastase that has previously been isolated from adult hookworms. Site-directed mutagenesis of the predicted P1 inhibitory reactive site amino acid confirmed the role of Met(26) in mediating inhibition of the three target serine proteases. By using reverse transcription-PCR, it was demonstrated that the level of AceKI gene expression increased following activation of third-stage larvae with serum and that the highest level of expression was reached in the adult stage of the parasite. Immunohistochemistry studies performed with polyclonal immunoglobulin G raised against recombinant AceKI showed that the inhibitor localized to the subcuticle of the adult hookworm, suggesting that it has a potential in vivo role in neutralizing intestinal proteases at the surface of the parasite. Immunization with recombinant AceKI was shown to confer partial protection against hookworm-associated growth delay without a measurable effect on anemia. Taken together, the data suggest that AceKI plays a role in the pathogenesis of hookworm-associated malnutrition and growth delay, perhaps through inhibition of nutrient absorption in infected hosts.
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Affiliation(s)
- Daniel Chu
- Child Health Research Center, Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut 06520-8081, USA
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