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Abstract
Hemolysins are a class of proteins defined by their ability to lyse red cells but have been described to exhibit pleiotropic functions. These proteins have been extensively studied in bacteria and more recently in fungi. Within the last decade, a number of studies have characterized fungal hemolysins and revealed a fascinating yet diverse group of proteins. The purpose of this review is to provide a synopsis of the known fungal hemolysins with an emphasis on those belonging to the aegerolysin protein family. New insight and perspective into fungal hemolysins in biotechnology and health are additionally presented.
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Affiliation(s)
- Ajay P Nayak
- Allergy and Clinical Immunology Branch, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505, USA.
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2
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Differences between group X and group V secretory phospholipase A(2) in lipolytic modification of lipoproteins. Cell Mol Biol Lett 2012; 17:459-78. [PMID: 22706677 PMCID: PMC6275602 DOI: 10.2478/s11658-012-0019-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 05/31/2012] [Indexed: 11/20/2022] Open
Abstract
Secretory phospholipases A(2) (sPLA(2)s) are a diverse family of low molecular mass enzymes (13-18 kDa) that hydrolyze the sn-2 fatty acid ester bond of glycerophospholipids to produce free fatty acids and lysophospholipids. We have previously shown that group X sPLA(2) (sPLA(2)-X) had a strong hydrolyzing activity toward phosphatidylcholine in low-density lipoprotein (LDL) linked to the formation of lipid droplets in the cytoplasm of macrophages. Here, we show that group V sPLA(2) (sPLA(2)-V) can also cause the lipolysis of LDL, but its action differs remarkably from that of sPLA(2)-X in several respects. Although sPLA(2)-V released almost the same amount of fatty acids from LDL, it released more linoleic acid and less arachidonic acid than sPLA(2)-X. In addition, the requirement of Ca(2+) for the lipolysis of LDL was about 10-fold higher for sPLA(2)-V than sPLA(2)-X. In fact, the release of fatty acids from human serum was hardly detectable upon incubation with sPLA(2)-V in the presence of sodium citrate, which contrasted with the potent response to sPLA(2)-X. Moreover, sPLA(2)-X, but not sPLA(2)-V, was found to specifically interact with LDL among the serum proteins, as assessed by gel-filtration chromatography as well as sandwich enzyme-immunosorbent assay using anti-sPLA(2)-X and anti-apoB antibodies. Surface plasmon resonance studies have revealed that sPLA2-X can bind to LDL with high-affinity (K(d) = 3.1 nM) in the presence of Ca(2+). Selective interaction of sPLA(2)-X with LDL might be involved in the efficient hydrolysis of cell surface or intracellular phospholipids during foam cell formation.
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Berne S, Lah L, Sepčić K. Aegerolysins: structure, function, and putative biological role. Protein Sci 2009; 18:694-706. [PMID: 19309687 PMCID: PMC2762582 DOI: 10.1002/pro.85] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 01/19/2009] [Accepted: 01/26/2009] [Indexed: 12/13/2022]
Abstract
Aegerolysins, discovered in fungi, bacteria and plants, are highly similar proteins with interesting biological properties. Certain aegerolysins possess antitumoral, antiproliferative, and antibacterial activities. Further possible medicinal applications include their use in the prevention of atherosclerosis, or as vaccines. Additional biotechnological value of fungal aegerolysins lies in their involvement in development, which could improve cultivation of commercially important edible mushrooms. Besides, new insights on microheterogeneity of raft-like membrane domains could be gained by using aegerolysins as specific markers in cell and molecular biology. Although the exact function of aegerolysins in their producing organisms remains to be explained, they are biochemically well characterized all-beta structured proteins sharing the following common features: low isoelectric points, similar molecular weights (15-17 kDa), and stability in a wide pH range.
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Affiliation(s)
- Sabina Berne
- Medical Centre for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana1000 Ljubljana, Slovenia
| | - Ljerka Lah
- Ljerka Lah, Laboratory for Biosynthesis and Biotransformation, National Institute of Chemistry1000 Ljubljana, Slovenia
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana1000 Ljubljana, Slovenia
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Kumagai T. [Biological activity of Asp-hemolysin as a regulation factor to atherogenic effect by oxidized low-density lipoprotein]. YAKUGAKU ZASSHI 2007; 126:955-64. [PMID: 17016024 DOI: 10.1248/yakushi.126.955] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxidatively modified low-density lipoprotein (OxLDL) is present in atherosclerotic lesions and has been proposed to play an important role in atherogenesis. Asp-hemolysin, a hemolytic toxin from Aspergillus fumigatus, is a binding protein for OxLDL. This study was undertaken to clarify the biological activity of OxLDL and the potentially of Asp-hemolysin as a regulation factor to atherogenic effect by OxLDL. We first analyzed the interaction between OxLDL and blood coagulation factors, which are involved in the blood coagulation pathway. OxLDL caused prolongation of activated partial thromboplastin time (APTT) as a parameter of the intrinsic pathway of blood coagulation in a dose- and oxidation time-dependent manner. In addition, OxLDL significantly inhibited blood coagulation factor VIII, IX, and XI activity. Furthermore, we demonstrated that factor VIII binds to OxLDL. These results indicate that the binding of factor VIII to OxLDL affects the intrinsic pathway of the blood coagulation cascade. Next, to clarify the structure-function relationship of Asp-hemolysin, we expressed Asp-hemolysin in Escherichia coli as a fusion protein with a maltose-binding protein (MBP) and purified it by affinity chromatography. The purified recombinant Asp-hemolysin showed an immunoreactivity with the anti-Asp-hemolysin antibody. In addition, MBP-Asp-hemolysin fusion protein exhibited binding activity to Ox-LDL as did native Asp-hemolysin. Furthermore, to investigate the effect of the Asp-hemolysin-related peptide (P-21), a synthetic peptide derived from a region of Asp-hemolysin that is rich in positive charges, on macrophage proliferation induced by OxLDL. P-21 inhibited OxLDL-induced macrophage proliferation in a dose-dependent manner. In addition, the binding analysis of P-21 to OxLDL indicated that P-21 binds to OxLDL. These results indicate that P-21 inhibits the OxLDL-induced macrophage proliferation through binding of P-21 to OxLDL. In conclusion, we have shown that OxLDL affects the intrinsic pathway of blood coagulation, and its mechanism is dependent on the binding of factor VIII to OxLDL. Furthermore, we indicate the possibility that Asp-hemolysin is a useful tool to investigate the pathophysiological significance of OxLDL. In particular, since the P-21, an Asp-hemolysin-related peptide, inhibits the OxLDL-induced macrophage proliferation through binding of P-21 to OxLDL, further study on the binding mechanism between Asp-hemolysin-related peptide and OxLDL may provide important information on the prevention and treatment of atherosclerosis.
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Affiliation(s)
- Takeshi Kumagai
- Department of Environmental Health Science, Tohoku Pharmaceutical University, Sendai City, Japan.
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Abstract
Oxidized low-density lipoprotein (Ox-LDL) is known to be involved in the generation and progression of atherosclerosis. Ox-LDL has a number of potentially atherogenic effects on vascular cells, including uncontrol uptake by scavenger receptors. Asp-hemolysin, a hemolytic toxin from Aspergillus fumigatus, is a binding protein for Ox-LDL. This study was undertaken to clarify the binding specificity of Asp-hemolysin to Ox-LDL. We examined the binding specificity of Asp-hemolysin to Ox-LDL using several modified lipoproteins and scavenger-receptor ligands. Asp-hemolysin bound to Ox-LDL with shorter LDL oxidation times. However, Asp-hemolysin did not bind to acetylated LDL. The native high-density lipoprotein (n-HDL) and modified HDL (e.g., acetylated HDL, oxidized HDL) also had no Asp-hemolysin binding. Inhibitors of scavenger-receptor binding, including maleylated bovine serum albumin, polyinosinic acid, dextran sulfate, and fucoidin, had no effect on the binding of Ox-LDL to Asp-hemolysin. Surface plasmon-resonance studies revealed that Ox-LDL binds with high affinity (K(D)=0.63 microg/ml) to Asp-hemolysin. Furthermore, we have shown that Ox-LDL strongly inhibits the hemolytic activity of Asp-hemolysin and that the removal of lysophosphatidylcholine (lysoPC) from Ox-LDL abolished the inhibition. We also investigated the interaction between Asp-hemolysin and lysoPC as a typical lipid moiety of Ox-LDL. The binding of Asp-hemolysin to LDL oxidized for different times depended on the lysoPC content in each Ox-LDL. In addition, the inhibition of lysoPC production in Ox-LDL by phenylmethylsulfonyl fluoride (PMSF) pretreatment of LDL resulted in a marked decrease in Asp-hemolysin binding to PMSF-pretreated Ox-LDL. The binding analysis of Asp-hemolysin to lysoPC revealed that Asp-hemolysin binds directly to lysoPC. We conclude that Asp-hemolysin is a specific binding protein with high affinity for Ox-LDL and that its binding specificity is distinct from any receptor for Ox-LDL.
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Affiliation(s)
- Yoichi Kudo
- Sendai Hospital of East Japan Railway Company, Sendai, Japan.
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Sakurai N, Kaneko J, Kamio Y, Tomita T. Cloning, expression, and pore-forming properties of mature and precursor forms of pleurotolysin, a sphingomyelin-specific two-component cytolysin from the edible mushroom Pleurotus ostreatus. ACTA ACUST UNITED AC 2004; 1679:65-73. [PMID: 15245918 DOI: 10.1016/j.bbaexp.2004.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2001] [Revised: 05/04/2004] [Accepted: 05/06/2004] [Indexed: 10/26/2022]
Abstract
Pleurotolysin, a sphingomyelin-specific cytolysin consisting of A (17 kDa) and B (59 kDa) components from the basidiomycete Pleurotus ostreatus, assembles into a transmembrane pore complex. Here, we cloned complementary and genomic DNAs encoding pleurotolysin, and studied pore-forming properties of recombinant proteins. The genomic regions encoding pleurotolysin A and B contained two and eight introns, respectively, and putative promoter sequences. The complementary DNA (cDNA) for pleurotolysin A encoded 138 amino acid residues, and the predicted product was identical with natural pleurotolysin A, except for the presence of the first methionine. Recombinant pleurotolysin A lacking the first methionine was purified as a 17-kDa protein with sphingomyelin-binding activity. The cDNA for pleurotolysin B encoded a precursor consisting of 523 amino acid residues, of which N-terminal 48 amino acid residues were absent in natural pleurotolysin B. Mature and precursor forms of pleurotolysin B were expressed as insoluble 59- and 63-kDa proteins, respectively, which were unfolded with 8 M urea and refolded by 100-fold dilution with 10 mM Tris-HCl buffer, pH 8.5. Although neither recombinant pleurotolysin A nor B alone was hemolytically active at higher concentrations of up to 100 mg/ml, they cooperatively assembled into a membrane pore complex on human erythrocytes and lysed the cell as efficiently as the natural proteins at nanomolar concentrations. In contrast, the precursor of pleurotolysin B was much less hemolytically active than mature pleurotolysin B in the presence of pleurotolysin A.
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Affiliation(s)
- Nobuki Sakurai
- Department of Microbial Biotechnology, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 981-8555, Japan
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Berne S, Krizaj I, Pohleven F, Turk T, Macek P, Sepcić K. Pleurotus and Agrocybe hemolysins, new proteins hypothetically involved in fungal fruiting. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1570:153-9. [PMID: 12020804 DOI: 10.1016/s0304-4165(02)00190-3] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Novel hemolytic proteins, ostreolysin and aegerolysin, were purified from the fruiting bodies of the edible mushrooms Pleurotus ostreatus and Agrocybe aegerita. Both ostreolysin and aegerolysin have a molecular weight of about 16 kDa, have low isoelectric points of 5.0 and 4.85, are thermolabile, and hemolytic to bovine erythrocytes at nanomolar concentrations. Their activity is impaired by micromolar Hg(2+) but not by membrane lipids and serum low-density lipoproteins (LDL). The sequence of respectively 50 and 10 N-terminal amino acid residues of ostreolysin and aegerolysin has been determined and found to be highly identical with a cDNA-derived amino acid sequence of putative Aa-Pri1 protein from the mushroom A. aegerita, Asp-hemolysin from Aspergillus fumigatus, and two bacterial hemolysin-like proteins expressed during sporulation. We found that ostreolysin is expressed during formation of primordia and fruiting bodies, which is in accord with previous finding that the Aa-Pri1 gene is specifically expressed during fruiting initiation. It is suggestive that the isolated hemolysins play an important role in initial phase of fungal fruiting.
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Affiliation(s)
- Sabina Berne
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, 1000 Ljubljana, Slovenia
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Kumagai T, Kudo Y, Fukuchi Y, Ebina K, Yokota K. Expression of a synthetic gene encoding the Asp-hemolysin from Aspergillus fumigatus in Escherichia coli. Biol Pharm Bull 2002; 25:115-7. [PMID: 11824538 DOI: 10.1248/bpb.25.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Asp-hemolysin is a hemolytic toxin from Aspergillus fumigatus and is a specific binding protein with high affinity for oxidized low density lipoprotein (Ox-LDL). As a first step in clarifying the structure-function relationship of Asp-hemolysin, we expressed Asp-hemolysin in Escherichia coli (E. coli) as a fusion protein with a maltose-binding protein (MBP) and purified it by affinity chromatography on an amylose resin. The apparent molecular size of the protein produced by E. coli was approximately 57 kDa, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. This is consistent with the predicted molecular size of 56.9 kDa for a fusion protein which includes 14.2 kDa of Asp-hemolysin and 42.7 kDa from MBP. The purified recombinant Asp-hemolysin showed an immunoreactivity with the anti-Asp-hemolysin antibody as revealed by western blot analysis. Furthermore, in dot blot analysis, MBP-Asp-hemolysin fusion protein exhibited binding activity to Ox-LDL as did native Asp-hemolysin.
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Affiliation(s)
- Takeshi Kumagai
- The First Department of Hygienic Chemistry, Tohoku Pharmaceutical University, Sendai, Japan.
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Kumagai T, Nagata T, Kudo Y, Fukuchi Y, Ebina K, Yokota K. [Effects of low density lipoprotein and oxidized low density lipoprotein on the cytotoxic activity of Asp-hemolysin to murine macrophages]. YAKUGAKU ZASSHI 2001; 121:277-81. [PMID: 11305045 DOI: 10.1248/yakushi.121.277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the effects of human low density lipoprotein (LDL) and oxidized LDL (Ox-LDL) on the cytotoxic activity of Asp-hemolysin from Aspergillus fumigatus Fresenius-Muramatsu strain to mouse peritoneal macrophages (M phi). The inhibitory effects of LDL and Ox-LDL on the cytotoxic activity of Asp-hemolysin to M phi increased in a dose-dependent manner, and the effect of Ox-LDL was greater than the inhibitory effect of LDL. Furthermore, the binding of Asp-hemolysin to LDL or Ox-LDL was observed by western blot analysis of the culture medium. These results suggest that the inhibition by LDL or Ox-LDL on the cytotoxic activity of Asp-hemolysin to M phi was due to the binding of LDL or Ox-LDL to Asp-hemolysin in the culture medium.
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Affiliation(s)
- T Kumagai
- First Department of Hygienic Chemistry, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
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Abstract
Aspergillus fumigatus is one of the most ubiquitous of the airborne saprophytic fungi. Humans and animals constantly inhale numerous conidia of this fungus. The conidia are normally eliminated in the immunocompetent host by innate immune mechanisms, and aspergilloma and allergic bronchopulmonary aspergillosis, uncommon clinical syndromes, are the only infections observed in such hosts. Thus, A. fumigatus was considered for years to be a weak pathogen. With increases in the number of immunosuppressed patients, however, there has been a dramatic increase in severe and usually fatal invasive aspergillosis, now the most common mold infection worldwide. In this review, the focus is on the biology of A. fumigatus and the diseases it causes. Included are discussions of (i) genomic and molecular characterization of the organism, (ii) clinical and laboratory methods available for the diagnosis of aspergillosis in immunocompetent and immunocompromised hosts, (iii) identification of host and fungal factors that play a role in the establishment of the fungus in vivo, and (iv) problems associated with antifungal therapy.
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Affiliation(s)
- J P Latgé
- Laboratoire des Aspergillus, Institut Pasteur, 75015 Paris, France.
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Fukuchi Y, Kudo Y, Kumagai T, Ebina K, Yokota K. Oxidized low density lipoprotein inhibits the hemolytic activity of Asp-hemolysin from Aspergillus fumigatus. FEMS Microbiol Lett 1998; 167:275-80. [PMID: 9809428 DOI: 10.1111/j.1574-6968.1998.tb13239.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
We have examined the effect of chemically modified human low density lipoproteins (LDLs), acetylated LDL and oxidized LDL, on the hemolytic activity of Asp-hemolysin. Oxidized LDL, but not acetylated LDL, inhibited the hemolytic activity of this toxin. The inhibitory effects of oxidized LDL increased with the time of Cu(2+)-induced LDL oxidation. Similar inhibition was observed in the filtrate which was separated from the incubation mixture of Asp-hemolysin with oxidized LDL (for 2 h of oxidation) following ultrafiltration through a membrane with a molecular mass cutoff of 100,000. However, at longer LDL oxidation times, the inhibition by the filtrates was less than the control mixture without ultrafiltration. We suggest that the inhibition by oxidized LDL was due to the binding of oxidized LDL to Asp-hemolysin at shorter LDL oxidation times.
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Affiliation(s)
- Y Fukuchi
- Japanese Red Cross Sendai Hospital, Sendai, Japan.
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