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Albulescu LO, Westhorpe A, Clare RH, Woodley CM, James N, Kool J, Berry NG, O’Neill PM, Casewell NR. Optimizing drug discovery for snakebite envenoming via a high-throughput phospholipase A2 screening platform. Front Pharmacol 2024; 14:1331224. [PMID: 38273832 PMCID: PMC10808766 DOI: 10.3389/fphar.2023.1331224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/19/2023] [Indexed: 01/27/2024] Open
Abstract
Snakebite envenoming is a neglected tropical disease that causes as many as 1.8 million envenomings and 140,000 deaths annually. To address treatment limitations that exist with current antivenoms, the search for small molecule drug-based inhibitors that can be administered as early interventions has recently gained traction. Snake venoms are complex mixtures of proteins, peptides and small molecules and their composition varies substantially between and within snake species. The phospholipases A2 (PLA2) are one of the main pathogenic toxin classes found in medically important viper and elapid snake venoms, yet varespladib, a drug originally developed for the treatment of acute coronary syndrome, remains the only PLA2 inhibitor shown to effectively neutralise venom toxicity in vitro and in vivo, resulting in an extremely limited drug portfolio. Here, we describe a high-throughput drug screen to identify novel PLA2 inhibitors for repurposing as snakebite treatments. We present method optimisation of a 384-well plate, colorimetric, high-throughput screening assay that allowed for a throughput of ∼2,800 drugs per day, and report on the screening of a ∼3,500 post-phase I repurposed drug library against the venom of the Russell's viper, Daboia russelii. We further explore the broad-spectrum inhibitory potential and efficacy of the resulting top hits against a range of medically important snake venoms and demonstrate the utility of our method in determining drug EC50s. Collectively, our findings support the future application of this method to fully explore the chemical space to discover novel PLA2-inhibiting drugs of value for preventing severe pathology caused by snakebite envenoming.
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Affiliation(s)
- Laura-Oana Albulescu
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Adam Westhorpe
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Rachel H. Clare
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Nivya James
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Jeroen Kool
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Neil G. Berry
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Paul M. O’Neill
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Kiran KS, Kameshwar VH, Mudnakudu Nagaraju KK, Nagalambika P, Varadaraju KR, Karthik NA, Dugganaboyana GK, Nanjunda Swamy S, Krishna KL, Kumar JR. Diosmin: A Daboia russelii venom PLA 2s inhibitor- purified, and characterized from Oxalis corniculata L medicinal plant. JOURNAL OF ETHNOPHARMACOLOGY 2024; 318:116977. [PMID: 37544341 DOI: 10.1016/j.jep.2023.116977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/25/2023] [Accepted: 07/27/2023] [Indexed: 08/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Oxalis corniculata L is a medicinal plant that belongs to the Oxalidaceae family. It is a little, slow-growing plant with a frail appearance typically found in mild temperate and tropical areas like Pakistan and India. This plant also includes many other bioactive substances, including alkaloids, flavonoids, terpenoids, cardiac glycosides, saponins, phlobatannins, and steroids. AIM OF THE STUDY To investigate the anti-inflammatory effects of Compound diosmin, which is derived from Oxalis corniculata L, on VRV-PL-5 and VRV-PL-8a isolated from Vipera russelli. MATERIALS AND METHODS Extraction, purification, and characterization of bioactive by TLC, HPTLC, FT-IR analysis, UV-Vis spectrophotometer, LC-MS/MS Analysis, NMR, XRD Analysis, In vitro evaluation, Circular dichroism spectroscopy, in vivo, and in silico studies. RESULTS In this study, the extract of Oxalis corniculata was evaluated for its in vitro and in vivo anti-inflammatory effect against PLA2. The methanolic extract decreased hemolytic activity by about 60% at 1:75 w/w and neutralized the hemolytic activity completely at 1:100 w/w concentration. Diosmin inhibited VRV-PL-5 and VRV-PL-8a in a dose-dependent manner, with the extent of inhibition being about 56% for VRV-PL-5120 μM and VRV-PL-8a by 62% at the same concentration with IC50 concentrations of 87.08 μM for VRV-PL-5 and 82.08 μM for VRV-PL-8a, while at 75 μM. Diosmin inhibited the hemolytic activity of VRV-PL-5 by about 85%, and at the same concentration, VRV-PL-8a inhibited by about 75%. UV-CD spectra at the IC50 concentration of diosmin disrupted the secondary structure of VRV-PL-5 &VRV-PL-8a. In vivo, studies showed decreased myotoxicity and cardiotoxicity of the VRV-PL-5 &VRV-PL-8a, which was seen in the decrease in cytoplasmic markers LDH and CPK levels in the serum when incubated with diosmin. Furthermore, Histopathological studies of Muscles and lungs revealed that diosmin considerably protects against cellular abnormality caused by VRV-PL-5 & VRV-PL-8a. Molecular docking, MM/GBSA, and molecular dynamics simulation studies show that the diosmin is a potent inhibitor for VRV-PL-5 and VRV-PL-8a. CONCLUSION This study shows that diosmin is a potentially effective VRV-PL-5 and VRV-PL-8a.
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Affiliation(s)
- K S Kiran
- Division of Biochemistry, School of Life Science, JSS Academy of Higher Education and Research, Mysore-15, India
| | - Vivek Hamse Kameshwar
- Department of Biochemistry, Adichunchanagiri Institute of Medical Sciences, Adichunchanagiri University, B. G. Nagara- 571448, Nagamangala (T), Mandya (D), Karnataka, India; Department of Biotechnology, Adichunchanagiri School of Natural Sciences, ACU-CRI, Adichunchanagiri University, B. G. Nagara- 571448, Nagamangala (T), Mandya (D), Karnataka, India
| | | | - Prasad Nagalambika
- Department of Microbiology, School of Life Sciences, JSS Academy of Higher Education and Research, Mysore-15, India
| | - Kavitha Raj Varadaraju
- Division of Biochemistry, School of Life Science, JSS Academy of Higher Education and Research, Mysore-15, India
| | - N Awathade Karthik
- Division of Biochemistry, School of Life Science, JSS Academy of Higher Education and Research, Mysore-15, India
| | - Guru Kumar Dugganaboyana
- Division of Biochemistry, School of Life Science, JSS Academy of Higher Education and Research, Mysore-15, India
| | - S Nanjunda Swamy
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technological University, Mysore, India
| | - K L Krishna
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education and Research, Mysore-15, India
| | - J R Kumar
- Division of Biochemistry, School of Life Science, JSS Academy of Higher Education and Research, Mysore-15, India.
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Chaisakul J, Khow O, Wiwatwarayos K, Rusmili MRA, Prasert W, Othman I, Abidin SAZ, Charoenpitakchai M, Hodgson WC, Chanhome L, Chaiyabutr N. A Biochemical and Pharmacological Characterization of Phospholipase A 2 and Metalloproteinase Fractions from Eastern Russell's Viper ( Daboia siamensis) Venom: Two Major Components Associated with Acute Kidney Injury. Toxins (Basel) 2021; 13:521. [PMID: 34437392 PMCID: PMC8402394 DOI: 10.3390/toxins13080521] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/19/2021] [Accepted: 07/21/2021] [Indexed: 12/21/2022] Open
Abstract
Acute kidney injury (AKI) following Eastern Russell's viper (Daboia siamensis) envenoming is a significant symptom in systemically envenomed victims. A number of venom components have been identified as causing the nephrotoxicity which leads to AKI. However, the precise mechanism of nephrotoxicity caused by these toxins is still unclear. In the present study, we purified two proteins from D. siamensis venom, namely RvPLA2 and RvMP. Protein identification using LCMS/MS confirmed the identity of RvPLA2 to be snake venom phospholipase A2 (SVPLA2) from Thai D. siamensis venom, whereas RvMP exhibited the presence of a factor X activator with two subunits. In vitro and in vivo pharmacological studies demonstrated myotoxicity and histopathological changes of kidney, heart, and spleen. RvPLA2 (3-10 µg/mL) caused inhibition of direct twitches of the chick biventer cervicis muscle preparation. After administration of RvPLA2 or RvMP (300 µg/kg, i.p.) for 24 h, diffuse glomerular congestion and tubular injury with minor loss of brush border were detected in envenomed mice. RvPLA2 and RvMP (300 µg/kg; i.p.) also induced congestion and tissue inflammation of heart muscle as well as diffuse congestion of mouse spleen. This study showed the significant roles of PLA2 and SVMP in snake bite envenoming caused by Thai D. siamensis and their similarities with observed clinical manifestations in envenomed victims. This study also indicated that there is a need to reevaluate the current treatment strategies for Thai D. siamensis envenoming, given the potential for irreversible nephrotoxicity.
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Affiliation(s)
- Janeyuth Chaisakul
- Department of Pharmacology, Phramongkutklao College of Medicine, Bangkok 10400, Thailand;
| | - Orawan Khow
- Queen Saovabha Memorial Institute, Thai Red Cross Society, Bangkok 10330, Thailand; (O.K.); (L.C.); (N.C.)
| | | | - Muhamad Rusdi Ahmad Rusmili
- Kulliyyah of Pharmacy, International Islamic University Malaysia, Bandar Indera Mahkota, Kuantan 25200, Malaysia;
| | - Watcharamon Prasert
- Department of Pharmacology, Phramongkutklao College of Medicine, Bangkok 10400, Thailand;
| | - Iekhsan Othman
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway 46150, Malaysia; (I.O.); (S.A.Z.A.)
| | - Syafiq Asnawi Zainal Abidin
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway 46150, Malaysia; (I.O.); (S.A.Z.A.)
| | | | - Wayne C. Hodgson
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, VIC 3800, Australia;
| | - Lawan Chanhome
- Queen Saovabha Memorial Institute, Thai Red Cross Society, Bangkok 10330, Thailand; (O.K.); (L.C.); (N.C.)
| | - Narongsak Chaiyabutr
- Queen Saovabha Memorial Institute, Thai Red Cross Society, Bangkok 10330, Thailand; (O.K.); (L.C.); (N.C.)
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Garcia A, Deplazes E, Aili S, Padula MP, Touchard A, Murphy C, Mirissa Lankage U, Nicholson GM, Cornell B, Cranfield CG. Label-Free, Real-Time Phospholipase-A Isoform Assay. ACS Biomater Sci Eng 2020; 6:4714-4721. [PMID: 33455186 DOI: 10.1021/acsbiomaterials.0c00632] [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] [Indexed: 01/08/2023]
Abstract
Phospholipase-A (PLA) enzymes catalyze the hydrolysis of ester bonds in select glycerophospholipids. Sensors for rapidly measuring the PLA activity in biological samples have relevance in the study of venom compositions and in medical diagnostics for the diagnosis of diseases such as acute pancreatitis. Current PLA sensor technologies are often restricted by the time it takes to prepare an assay, the necessity of using fluorescent labels, or the fact they might require strict pH control of the buffer vehicles used. Here we present a tethered bilayer lipid membrane (tBLM) impedance sensor array for the rapid and real-time detection of PLA, which includes the ability to selectively detect phospholipase-A2 (PLA2) from phospholipase-A1 (PLA1) isoforms. Comparing the activity of PLA1 and PLA2 in an array of tBLMs composed of ether phospholipids, ester phospholipids or ether-ester phospholipids allows for the rapid and reliable distinction between the isoforms, as measured using swept-frequency electrical impedance spectroscopy. After testing the assay using pure enzymes, we demonstrate the capacity of the sensor to identify specific PLA2-type, calcium-dependent activity from the venom of the South American bullet ant, Paraponera clavata, at a concentration of 1 μg/mL. The specificity of the phospholipase activity was corroborated using matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry. As further validation, we tested the activities of a PLA1 isoform in the presence of different buffers commonly used in biology and biochemistry experiments. Sensitivity testing shows that PLA1 can be detected at an activity as low as 0.06 U/mL. The rapid and reliable detection of phospholipases presented in this study has potential applications in the study of animal venoms as well as in lipase bioreactors and point-of-care devices.
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Affiliation(s)
- Alvaro Garcia
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Evelyne Deplazes
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Samira Aili
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Matthew P Padula
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Axel Touchard
- CNRS, UMR Ecologie des Forêts de Guyane, AgroParisTech, CIRAD, INRA, Université de Guyane, Université des Antilles, Campus Agronomique, BP316, Kourou Cedex 97379, France
| | - Christopher Murphy
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Upeksha Mirissa Lankage
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Graham M Nicholson
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Bruce Cornell
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.,SDx Surgical Diagnostics Pty Ltd., U6 30-32 Barcoo Street, Roseville, New South Wales 2069, Australia
| | - Charles G Cranfield
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
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Snake Venom PLA 2, a Promising Target for Broad-Spectrum Antivenom Drug Development. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6592820. [PMID: 29318152 PMCID: PMC5727668 DOI: 10.1155/2017/6592820] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/30/2017] [Indexed: 12/04/2022]
Abstract
Snakebite envenomation is a neglected global health problem, causing substantial mortality, disability, and psychological morbidity, especially in rural tropical and subtropical zones. Antivenin is currently the only specific medicine for envenomation. However, it is restricted by cold storage, snakebite diagnosis, and high price. Snake venom phospholipase A2s (svPLA2s) are found in all kinds of venomous snake families (e.g., Viperidae, Elapidae, and Colubridae). Along with their catalytic activity, svPLA2s elicit a wide variety of pharmacological effects that play a pivotal role in envenomation damage. Hence, neutralization of the svPLA2s could weaken or inhibit toxic damage. Here we overviewed the latest knowledge on the distribution, pathophysiological effects, and inhibitors of svPLA2s to elucidate the potential for a novel, wide spectrum antivenom drug targeting svPLA2s.
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Unveiling the complexities of Daboia russelii venom, a medically important snake of India, by tandem mass spectrometry. Toxicon 2015; 107:266-81. [DOI: 10.1016/j.toxicon.2015.06.027] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 06/24/2015] [Accepted: 06/30/2015] [Indexed: 10/23/2022]
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Kumar JR, Basavarajappa BS, Vishwanath BS, Gowda TV. Biochemical and pharmacological characterization of three toxic phospholipase A2s from Daboia russelii snake venom. Comp Biochem Physiol C Toxicol Pharmacol 2015; 168:28-38. [PMID: 25478875 DOI: 10.1016/j.cbpc.2014.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/19/2014] [Accepted: 11/26/2014] [Indexed: 10/24/2022]
Abstract
Three isoenzymes of phospholipase A2 (PLA2), VRV-PL-IIIc, VRV-PL-VII, and VRV-PL-IX were isolated from Daboia russelii snake venom. The venom, upon gel filtration on Sephadex G-75 column, resolved into six peaks (DRG75 I-VI). The VRV-PL-IIIc was purified by subjecting DRG75II to homogeneity by rechromatography in the presence of 8M urea on Sephadex G-75 column. The other two isoenzymes VRV-PL-VII and VRV-PL-IX were purified by subjecting DRG75III to ion exchange chromatography on CM-Sephadex C-25 column. Mol wt. for the three PLA2s, VRV-PL-IIIc, VRV-PL-VII, and VRV-PL-IX are 13.003kDa, 13.100kDa and 12.531kDa respectively. The VRV-PL-IIIc is not lethal to mice up to 14mg/kg body weight but it affects blood sinusoids and causes necrosis of the hepatocytes in liver. It causes hemorrhage in kidney and shrinkage of renal corpuscles and renal tubules. The LD50s for VRV-PL-VII and VRV-PL-IX are 7 and 7.5mg/kg body weight respectively. They induced neurotoxic symptoms similar to VRV-PL-V. All the three PLA2s are anticoagulant and induced varying degree of edema in the foot pads of mice. VRV-PL-V and VRV-PL-VII are shown to act as pre and post synaptic toxins, while VRV-PL-IX acts as presynaptic toxin. This is evident from experiments conducted on cultured hippocampal neurons by patch clamp electrophysiology.
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Affiliation(s)
- J R Kumar
- Department of studies in Biochemistry University of Mysore, Manasagangothri, Mysore 570006, India; Post Graduate Department of Biochemistry, JSS College, Ooty Road, Mysore 570025, India.
| | - Balapal S Basavarajappa
- Division of Analytical Psychopharmacology, New York State Psychiatric Institute, USA; Department of Psychiatry, Orangeburg, NY 10962, USA; Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - B S Vishwanath
- Department of studies in Biochemistry University of Mysore, Manasagangothri, Mysore 570006, India
| | - T Veerabasappa Gowda
- Department of studies in Biochemistry University of Mysore, Manasagangothri, Mysore 570006, India
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Kumar JR, Basavarajappa BS, Arancio O, Aranha I, Gangadhara NS, Yajurvedi HN, Gowda TV. Isolation and characterization of "Reprotoxin", a novel protein complex from Daboia russelii snake venom. Biochimie 2008; 90:1545-59. [PMID: 18573307 DOI: 10.1016/j.biochi.2008.05.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 05/01/2008] [Indexed: 11/17/2022]
Abstract
In snake venoms, non-covalent protein-protein interaction leads to protein complexes with synergistic and, at times, distinct pharmacological activities. Here we describe a new protein complex containing phospholipaseA(2) (PLA(2)), protease, and a trypsin inhibitor. It is isolated from the venom of Daboia russelii by gel permeation chromatography, on a Sephadex G-75 column. This 44.6 kDa complex exhibits only phospholipase A(2) activity. In the presence of 8M urea it is well resolved into protease (29.1 kDa), PLA(2) (13 kDa), and trypsin inhibitor (6.5 kDa) peaks. The complex showed an LD(50) of 5.06 mg/kg body weight in mice. It inhibited the frequency of spontaneous release of neurotransmitter in hippocampal neurons. It also caused peritoneal bleeding, and edema in the mouse foot pads. Interestingly, the complex caused degeneration of both the germ cells and the mouse Leydig cells of mouse testis. A significant reduction in both the diameter of the seminiferous tubules and height of the seminiferous epithelia were observed following intraperitoneal injection of the sub-lethal dose (3 mg/kg body weight). This effect of the toxin is supported by the increase in the activities of acid and alkaline phosphatases and the nitric oxide content in the testes, and a decrease in the ATPase activity. Because of its potent organ atrophic effects on the reproductive organs, the toxin is named "Reprotoxin". This is the first report demonstrating toxicity to the reproductive system by a toxin isolated from snake venom.
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Affiliation(s)
- J R Kumar
- Department of Biochemistry, University of Mysore, Manasagangothri, Mysore, India
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Tsai IH, Tsai HY, Wang YM, Tun-Pe, Warrell DA. Venom phospholipases of Russell's vipers from Myanmar and eastern India--cloning, characterization and phylogeographic analysis. BIOCHIMICA ET BIOPHYSICA ACTA 2007; 1774:1020-8. [PMID: 17611171 DOI: 10.1016/j.bbapap.2007.04.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 04/22/2007] [Accepted: 04/24/2007] [Indexed: 10/23/2022]
Abstract
Venoms of Russell's vipers (genus Daboia) are known for their deadly coagulopathic and other effects. We herein studied various isoforms of venom phospholipases A(2) (PLAs) from two Daboia species at their geographic boundary. From Myanmar Daboia siamensis venom (designated as DsM), four PLAs (designated DsM-aI, aI', aII' and bI') were purified, and the cDNAs encoding two acidic (DsM-aI and aII) and two basic PLAs (DsM-bI and S1) were also cloned from its venom-glands. DsM-S1 is identical to the major venom PLA of southern India Daboia russelii, but the protein is absent from the venom. Additionally, four PLAs (designated DrK-aI, aII, bI and bII) were cloned from cDNA obtained from venom glands of a Kolkata D. russelii, and the PLAs were purified from the pooled venom (designated as DrK). The acidic DrK-aI is the most neurotoxic and lethal among these PLAs; DsM-aI which differs from DrK-aI by only the Phe2 substitution shows greatly reduced enzymatic activity and lethality. Both acidic PLAs do not form dimeric complex with basic PLAs in the same venoms. DsM-bI' is neurotoxic and lethal but its orthologous DrK-bI (97% identical to DsM-bI') is a much weaker toxin. Given the fact that most of the orthologous PLAs of DrK and DsM share 97-100% sequence identity, Daboia vipers of Myanmar and Kolkata must be closely related. Molecular phylogenetic analyses on 30 venom PLAs of Eurasian vipers' revealed co-evolution of five subtypes of venom PLAs in both Daboia and Vipera genera. Our results shed light on the intra- and inter-species variations and structure-function relationships of viperid venom PLAs.
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Affiliation(s)
- Inn-Ho Tsai
- Institute of Biological Chemistry, Academia Sinica, and College of Life Sciences, National Taiwan University, Taipei 106, Taiwan.
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Yang WL, Peng LS, Zhong XF, Wei JW, Jiang XY, Ye LT, Zou L, Tu HB, Wu WY, Xu AL. Functional expression and characterization of a recombinant phospholipase A2 from sea snake Lapemis hardwickii as a soluble protein in E. coli. Toxicon 2003; 41:713-21. [PMID: 12727275 DOI: 10.1016/s0041-0101(03)00047-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Three full-length phospholipase A(2) (PLA(2)) cDNAs from sea snake Lapemis hardwickii venom were cloned and sequenced in our previous study. In order to investigate their biological functions, we established a fusion expression system for PLA(2)-9 in E. coli. The open reading frame encoding mature peptide of PLA(2)-9 was subcloned into the vector pTRX. The Trx-PLA(2)-9 fusion protein was expressed as a soluble protein by IPTG induction at 23 degrees C. The fusion protein was purified with metal-chelate affinity chromatography and then cleaved by enterokinase. The mature recombinant PLA(2)-9 was further purified by ion-exchange chromatography and a final yield of approximately 2.5mg pure PLA(2)-9 from 1l of bacteria culture was obtained. The catalytic activity of recombinant PLA(2)-9 (rPLA(2)-9) was measured and found to be similar to native enzyme. As the Austrelaps superbus PLA(2), which shares 90% nucleotide sequence similarity to PLA(2)-9, the rPLA(2)-9 displayed the anti-platelet aggregation effect. Site-directed mutagenesis of the two conserved residues, His-48 and Asp-49, resulted in the loss of catalytic activity, however did not affect the inhibition effect of platelet aggregation suggesting that these two activities of sea snake PLA(2)-9 may be dissociated.
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Affiliation(s)
- Wen-Li Yang
- The Open Laboratory for Marine Functional Genomics of State High-Tech Development, Department of Biochemistry, College of Life Sciences, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275, People's Republic of China
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