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Li M, Mao K, Huang M, Liao Y, Fu J, Pan K, Shi Q, Gao B. Venomics Reveals the Venom Complexity of Sea Anemone Heteractis magnifica. Mar Drugs 2024; 22:71. [PMID: 38393042 PMCID: PMC10890322 DOI: 10.3390/md22020071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 02/25/2024] Open
Abstract
The venoms of various sea anemones are rich in diverse toxins, which usually play a dual role in capturing prey and deterring predators. However, the complex components of such venoms have not been well known yet. Here, venomics of integrating transcriptomic and proteomic technologies was applied for the first time to identify putative protein and peptide toxins from different tissues of the representative sea anemone, Heteractis magnifica. The transcriptomic analysis of H. magnifica identified 728 putative toxin sequences, including 442 and 381 from the tentacles and the column, respectively, and they were assigned to 68 gene superfamilies. The proteomic analysis confirmed 101 protein and peptide toxins in the venom, including 91 in the tentacles and 39 in the column. The integrated venomics also confirmed that some toxins such as the ShK-like peptides and defensins are co-expressed in both the tentacles and the column. Meanwhile, a homology analysis was conducted to predict the three-dimensional structures and potential activity of seven representative toxins. Altogether, this venomics study revealed the venom complexity of H. magnifica, which will help deepen our understanding of cnidarian toxins, thereby supporting the in-depth development of valuable marine drugs.
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Affiliation(s)
- Ming Li
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, Haikou 571199, China; (M.L.); (K.M.); (M.H.); (Y.L.); (J.F.); (K.P.)
| | - Kailin Mao
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, Haikou 571199, China; (M.L.); (K.M.); (M.H.); (Y.L.); (J.F.); (K.P.)
| | - Meiling Huang
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, Haikou 571199, China; (M.L.); (K.M.); (M.H.); (Y.L.); (J.F.); (K.P.)
| | - Yanling Liao
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, Haikou 571199, China; (M.L.); (K.M.); (M.H.); (Y.L.); (J.F.); (K.P.)
| | - Jinxing Fu
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, Haikou 571199, China; (M.L.); (K.M.); (M.H.); (Y.L.); (J.F.); (K.P.)
| | - Kun Pan
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, Haikou 571199, China; (M.L.); (K.M.); (M.H.); (Y.L.); (J.F.); (K.P.)
| | - Qiong Shi
- Laboratory of Aquatic Genomics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518057, China
- Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, Shenzhen 518081, China
| | - Bingmiao Gao
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, Haikou 571199, China; (M.L.); (K.M.); (M.H.); (Y.L.); (J.F.); (K.P.)
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Leychenko E, Isaeva M, Tkacheva E, Zelepuga E, Kvetkina A, Guzev K, Monastyrnaya M, Kozlovskaya E. Multigene Family of Pore-Forming Toxins from Sea Anemone Heteractis crispa. Mar Drugs 2018; 16:E183. [PMID: 29794988 PMCID: PMC6025637 DOI: 10.3390/md16060183] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 05/21/2018] [Accepted: 05/22/2018] [Indexed: 11/23/2022] Open
Abstract
Sea anemones produce pore-forming toxins, actinoporins, which are interesting as tools for cytoplasmic membranes study, as well as being potential therapeutic agents for cancer therapy. This investigation is devoted to structural and functional study of the Heteractis crispa actinoporins diversity. Here, we described a multigene family consisting of 47 representatives expressed in the sea anemone tentacles as prepropeptide-coding transcripts. The phylogenetic analysis revealed that actinoporin clustering is consistent with the division of sea anemones into superfamilies and families. The transcriptomes of both H. crispa and Heteractis magnifica appear to contain a large repertoire of similar genes representing a rapid expansion of the actinoporin family due to gene duplication and sequence divergence. The presence of the most abundant specific group of actinoporins in H. crispa is the major difference between these species. The functional analysis of six recombinant actinoporins revealed that H. crispa actinoporin grouping was consistent with the different hemolytic activity of their representatives. According to molecular modeling data, we assume that the direction of the N-terminal dipole moment tightly reflects the actinoporins' ability to possess hemolytic activity.
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Affiliation(s)
- Elena Leychenko
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159, Pr. 100 let Vladivostoku, Vladivostok 690022, Russia.
- School of Natural Sciences, Far Eastern Federal University, Sukhanova Street 8, Vladivostok 690091, Russia.
| | - Marina Isaeva
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159, Pr. 100 let Vladivostoku, Vladivostok 690022, Russia.
- School of Natural Sciences, Far Eastern Federal University, Sukhanova Street 8, Vladivostok 690091, Russia.
| | - Ekaterina Tkacheva
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159, Pr. 100 let Vladivostoku, Vladivostok 690022, Russia.
| | - Elena Zelepuga
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159, Pr. 100 let Vladivostoku, Vladivostok 690022, Russia.
| | - Aleksandra Kvetkina
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159, Pr. 100 let Vladivostoku, Vladivostok 690022, Russia.
| | - Konstantin Guzev
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159, Pr. 100 let Vladivostoku, Vladivostok 690022, Russia.
| | - Margarita Monastyrnaya
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159, Pr. 100 let Vladivostoku, Vladivostok 690022, Russia.
| | - Emma Kozlovskaya
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159, Pr. 100 let Vladivostoku, Vladivostok 690022, Russia.
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Peptide fingerprinting of the sea anemone Heteractis magnifica mucus revealed neurotoxins, Kunitz-type proteinase inhibitors and a new β-defensin α-amylase inhibitor. J Proteomics 2017; 173:12-21. [PMID: 29191747 DOI: 10.1016/j.jprot.2017.11.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/23/2017] [Accepted: 11/24/2017] [Indexed: 01/01/2023]
Abstract
Sea anemone mucus, due to its multiple and vital functions, is a valuable substance for investigation of new biologically active peptides. In this work, compounds of Heteractis magnifica mucus were separated by multistage liquid chromatography and resulting fractions were analyzed by MALDI-TOF MS. Peptide maps constructed according to the molecular masses and hydrophobicity showed presence of 326 both new and known peptides. Several major peptides from mucus were identified, including the sodium channel toxin RpII isolated earlier from H. magnifica, and four Kunitz-type proteinase inhibitors identical to H. crispa ones. Kunitz-type transcript diversity was studied and sequences of mature peptides were deduced. New β-defensin α-amylase inhibitor, a homolog of helianthamide from Stichodactyla helianthus, was isolated and structurally characterized. Overall, H. magnifica is a source of biologically active peptides with great pharmacological potential. BIOLOGICAL SIGNIFICANCE Proteinase and α-amylase inhibitors along with toxins are major components of H. magnifica mucus which play an important role in the successful existence of sea anemones. Obtained peptide maps create a basis for more accurate identification of peptides during future transcriptomic/genomic studies of sea anemone H. magnifica.
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Weber DK, Yao S, Rojko N, Anderluh G, Lybrand TP, Downton MT, Wagner J, Separovic F. Characterization of the Lipid-Binding Site of Equinatoxin II by NMR and Molecular Dynamics Simulation. Biophys J 2016; 108:1987-96. [PMID: 25902438 DOI: 10.1016/j.bpj.2015.03.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/09/2015] [Accepted: 03/12/2015] [Indexed: 12/26/2022] Open
Abstract
Equinatoxin II (EqtII) is a soluble, 20 kDa pore-forming protein toxin isolated from the sea anemone Actinia equina. Although pore formation has long been known to occur in distinct stages, including monomeric attachment to phospholipid membranes followed by detachment of the N-terminal helical domain and oligomerization into the final pore assembly, atomistic-level detail of the protein-lipid interactions underlying these events remains elusive. Using high-resolution solution state NMR of uniformly-(15)N-labeled EqtII at the critical micelle concentration of dodecylphosphocholine, we have mapped the lipid-binding site through chemical shift perturbations. Subsequent docking of an EqtII monomer onto a dodecylphosphocholine micelle, followed by 400 ns of all-atom molecular dynamics simulation, saw several high-occupancy lipid-binding pockets stabilized by cation-π, hydrogen bonding, and hydrophobic interactions; and stabilization of the loop housing the conserved arginine-glycine-aspartate motif. Additional simulation of EqtII with an N-acetyl sphingomyelin micelle, for which high-resolution NMR data cannot be obtained due to aggregate formation, revealed that sphingomyelin specificity might occur via hydrogen bonding to the 3-OH and 2-NH groups unique to the ceramide backbone by side chains of D109 and Y113; and main chains of P81 and W112. Furthermore, a binding pocket formed by K30, K77, and P81, proximate to the hinge region of the N-terminal helix, was identified and may be implicated in triggering pore formation.
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Affiliation(s)
- Daniel K Weber
- School of Chemistry, University of Melbourne, Victoria, Australia; Bio21 Institute, University of Melbourne, Victoria, Australia
| | - Shenggen Yao
- Bio21 Institute, University of Melbourne, Victoria, Australia
| | - Nejc Rojko
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Gregor Anderluh
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Terry P Lybrand
- Center for Structural Biology, Department of Chemistry, Vanderbilt University, Nashville, Tennessee
| | - Matthew T Downton
- IBM Research Collaboratory for Life Sciences, Victorian Life Sciences Computation Initiative, University of Melbourne, Victoria, Australia
| | - John Wagner
- IBM Research Collaboratory for Life Sciences, Victorian Life Sciences Computation Initiative, University of Melbourne, Victoria, Australia
| | - Frances Separovic
- School of Chemistry, University of Melbourne, Victoria, Australia; Bio21 Institute, University of Melbourne, Victoria, Australia.
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Valle A, Alvarado-Mesén J, Lanio M, Álvarez C, Barbosa J, Pazos I. The multigene families of actinoporins (part I): Isoforms and genetic structure. Toxicon 2015; 103:176-87. [DOI: 10.1016/j.toxicon.2015.06.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 05/31/2015] [Accepted: 06/23/2015] [Indexed: 11/24/2022]
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Oliveira JS, Fuentes-Silva D, King GF. Development of a rational nomenclature for naming peptide and protein toxins from sea anemones. Toxicon 2012; 60:539-50. [DOI: 10.1016/j.toxicon.2012.05.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/21/2012] [Accepted: 05/24/2012] [Indexed: 01/30/2023]
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Tkacheva ES, Leychenko EV, Monastyrnaya MM, Issaeva MP, Zelepuga EA, Anastuk SD, Dmitrenok PS, Kozlovskaya EP. New actinoporins from sea anemone Heteractis crispa: Cloning and functional expression. BIOCHEMISTRY (MOSCOW) 2011; 76:1131-9. [DOI: 10.1134/s0006297911100063] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Actinoporins from the sea anemones, tropical Radianthus macrodactylus and northern Oulactis orientalis: Comparative analysis of structure–function relationships. Toxicon 2010; 56:1299-314. [DOI: 10.1016/j.toxicon.2010.07.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 07/16/2010] [Accepted: 07/19/2010] [Indexed: 11/24/2022]
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Uechi GI, Toma H, Arakawa T, Sato Y. Molecular characterization on the genome structure of hemolysin toxin isoforms isolated from sea anemone Actineria villosa and Phyllodiscus semoni. Toxicon 2010; 56:1470-6. [PMID: 20837039 DOI: 10.1016/j.toxicon.2010.09.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 08/31/2010] [Accepted: 09/06/2010] [Indexed: 11/16/2022]
Abstract
We recently identified the existence of new isoforms of Avt-I (from sea anemone Actineria villosa) and Pstx20 (from sea anemone Phyllodiscus semoni) hemolytic toxins, and named them Avt-II and Pst-I. Avt-II and Pst-I differ in length by 14 and 7 bp, respectively, as compared to their corresponding isoform genes. Both newly found isoform genes have the coding regions with the identical length of 1033 bp. The restriction fragment length polymorphism analysis with endonuclease HphI was able to clearly distinguish between the two Avt isoforms, but not Pstx isoforms, and based on the densitometric analysis of DNA bands, it indicated that relative expression levels of Avt-I and Avt-II genes were 18.3% and 81.7%, respectively. PCR amplification of the two Avt isoform genes using the genomic DNA as template indicated the existence of two introns within each toxin isoform gene. The first intron with the identical 242 bp in length for both Avt isoform was found within the 5'-untranslated region, and the second intron with lengths of 654 bp and 661 bp in Avt-I and Avt-II isoforms, respectively, was found within the signal sequence coding region. This is for the first time to identify the existence of introns within hemolysin genes of sea anemone. Having several unique characteristics that have identified only for a new member of actinoporin family of A. villosa and P. semoni, e.g., strong toxicity and genes with introns, it is plausible to speculate that these toxins have a unique genetic evolutionary linage differed from that for other sea anemone hemolytic toxins.
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Affiliation(s)
- Gen-Ichiro Uechi
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto Nagasaki City, Nagasaki 852 8523, Japan
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Wang Y, Yap LL, Chua KL, Khoo HE. A multigene family of Heteractis magnificalysins (HMgs). Toxicon 2008; 51:1374-82. [DOI: 10.1016/j.toxicon.2008.03.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Revised: 02/29/2008] [Accepted: 03/04/2008] [Indexed: 11/17/2022]
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Nagata K, Hide M, Tanaka T, Ishii K, Izawa M, Sairenji T, Tomita K, Shimizu E. Anaphylactic shock caused by exposure to sea anemones. Allergol Int 2006; 55:181-4. [PMID: 17075255 DOI: 10.2332/allergolint.55.181] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 12/06/2005] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Since the first report of a dog that developed severe systemic symptoms in response to a second injection of sea anemone toxin by Richet and Portier in 1902, no clear human cases of anaphylaxis related to exposure to sea anemones has been reported in the literature. METHODS A 24-year-old man with an episode of local urticaria on his first contact with a sea anemone (Stichodactyla haddoni), developed dyspnea, severe urticaria and hypotension on exposure to water containing the dead bodies of the organism. To study whether this reaction was mediated by antigen-specific IgE, we performed a histamine release test with blood, Western blotting with serum and lymphocyte proliferating test with peripheral blood mononuclear cells of the patient, for the homogenate of sea anemones. RESULTS The homogenate of sea anemones induced histamine release from the blood of the patient, but it also induced histamine release from the blood of control subjects. Moreover, it also caused hemolysis of blood of all donors. However, Western-blotting demonstrated the presence of an 86 kd protein-specific IgE in the serum of the patient. CONCLUSIONS Protein antigen(s) in sea anemones may cause anaphylactic shock under the influence of the cytolytic effects and/or lymphocyte-stimulating activity elicited by the toxin of sea anemones.
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Affiliation(s)
- Keiko Nagata
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, Faculty of Medicine, Tottori University, Yonago, Tottori, Japan.
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Uechi GI, Toma H, Arakawa T, Sato Y. Molecular cloning and functional expression of hemolysin from the sea anemone Actineria villosa. Protein Expr Purif 2005; 40:379-84. [PMID: 15766880 DOI: 10.1016/j.pep.2004.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 12/04/2004] [Indexed: 11/17/2022]
Abstract
The full-length cDNA that encodes the hemolytic toxin Avt-I, with 226 amino acids, from the venomous sea anemone Actineria villosa has been cloned using the oligo-capping method. The cDNA contains 681bp open reading frame and its predicted amino acid sequences revealed that Avt-I was basic polypeptides without cysteine residues and Arg-Gly-Asp (RGD) motif sequence. The mature Avt-I has a predicted molecular weight of 19.6 kDa and its theoretical isoelectric point is 9.3. The Avt-I revealed 99, 61, 57, and 57% amino acid similarity with hemolytic toxins Pstx20, EqtII, StII, and HmT from Phyllodiscus semoni, Actinia Equina, Stichodactyla helianthus, and Heteractis magnifica, respectively. The characteristic amphiphilic alpha-helix structure was found at the N-terminal region of the mature Avt-I. Recombinant Avt-I (rAvt-I) was expressed in Escherichia coli BL21 (DE3) strain as a biologically active form and purified rAvt-I caused 50% hemolytic activity against 1% sheep erythrocytes at a concentration of 6.3 ng/ml (0.32 nM). M9Y medium led to more than 2-fold increase in rAvt-I yield than cultivation in Luria-Bertani medium.
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Affiliation(s)
- Gen-ichiro Uechi
- Division of Tropical Parasitology, Unit of Social and Environmental Medicine, School of Medicine, University of the Ryukyus, Nishihara, Okinawa 903-0215, Japan.
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Monastyrnaya MM, Zykova TA, Apalikova OV, Shwets TV, Kozlovskaya EP. Biologically active polypeptides from the tropical sea anemone Radianthus macrodactylus. Toxicon 2002; 40:1197-217. [PMID: 12165324 DOI: 10.1016/s0041-0101(02)00139-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Some biologically active polypeptides, three high and two low molecular weight cytolysins and four trypsin inhibitors were isolated from the sea anemone Radianthus macrodactylus and characterized. The purification steps involved acetone precipitation, gel filtration, ion-exchange, and affinity chromatography, and ion-exchange and reverse-phase HPLC. The relative molecular weight of high molecular weight Radianthus cytolysins named according to their N-terminal amino acids RTX-A (Ala), RTX-S (Ser) and RTX-G (Gly) was about 20,000. The isoelectric points were 9.8 for RTX-A and RTX-S, and 10.5 for RTX-G. The hemolytic activities of RTX-A, RTX-S and RTX-G were 3.5 x 10(4), 5.0 x10(4), and 1.0 x10(4)HU/mg, respectively, and were inhibited by sphingomyelin. The N-terminal amino acid sequence of RTX-A was determined as ALAGAIIAGAGLGLKILIEVLGEG-VKVKI-. Molecular weight of low molecular weight Radianthus cytolysins RmI, RmII, and of one trypsin inhibitor InI were 5100, 6100 and 7100, respectively. Isoelectric points for RmI and RmII were 9.2 and 9.3. Their hemolytic activity worked out 25 and 20 HU/mg, and was not inhibited by sphingomyelin. Toxicity of RmI and RmII was assessed by their histaminolytic activity. Amino acid composition of RmI and RmII was similar to that of tealiatoxin, histaminolytic cytolysin from the sea anemone Tealia felina.
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Affiliation(s)
- Margarita M Monastyrnaya
- Pacific Institute of Bioorganic Chemistry of the Far Eastern Branch of the Russian Academy of Sciences, pr. 100 let Vladivostoku 159, 690022, Vladivostok, Russian Federation.
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Abstract
More than 32 species of sea anemones have been reported to produce lethal cytolytic peptides and proteins. Based on their primary structure and functional properties, cytolysins have been classified into four polypeptide groups. Group I consists of 5-8 kDa peptides, represented by those from the sea anemones Tealia felina and Radianthus macrodactylus. These peptides form pores in phosphatidylcholine containing membranes. The most numerous is group II comprising 20 kDa basic proteins, actinoporins, isolated from several genera of the fam. Actiniidae and Stichodactylidae. Equinatoxins, sticholysins, and magnificalysins from Actinia equina, Stichodactyla helianthus, and Heteractis magnifica, respectively, have been studied mostly. They associate typically with sphingomyelin containing membranes and create cation-selective pores. The crystal structure of equinatoxin II has been determined at 1.9A resolution. Lethal 30-40 kDa cytolytic phospholipases A(2) from Aiptasia pallida (fam. Aiptasiidae) and a similar cytolysin, which is devoid of enzymatic activity, from Urticina piscivora, form group III. A thiol-activated cytolysin, metridiolysin, with a mass of 80 kDa from Metridium senile (fam. Metridiidae) is a single representative of the fourth family. Its activity is inhibited by cholesterol or phosphatides. Biological, structure-function, and pharmacological characteristics of these cytolysins are reviewed.
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Affiliation(s)
- Gregor Anderluh
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111,1000 Ljubljana, Slovenia
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