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Huang Y, Liu H, Zhou Y, Lu Z, Pu Y, Zhang H. Cloning and functional characterization of the oxidative squalene cyclase gene in the deep-sea holothurian Chiridota sp. Gene 2024; 894:147971. [PMID: 37949417 DOI: 10.1016/j.gene.2023.147971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 09/10/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023]
Abstract
Saponins derived from holothurians have high potential medicinal value. However, the de novo synthesis of the derivatization of triterpenes is still unclear. Oxidative squalene cyclase (OSC) can catalyze 2,3-Oxidosqualene into diverse products that serve as important precursors for triterpene synthesis. However, the function of theOSCgene in Chiridotasp. hasnot been elucidated. In this study, an OSCgenederived from the deep-sea holothurianChiridota sp. was cloned and characterized functionally in a yeast system. The open reading frame of the OSC gene was 2086 bp, which encoded 695 amino acids. The Chiridota sp. OSC gene has a similarity of 66.89 % to the OSC of other holothurian species and 63.51 % to that of Acanthaster planci. The phylogenetic tree showed that the echinozoan OSCsclustered together, and then they formeda sister group to fungi and plant homologs. Chiridota sp. OSC catalyzed 2,3-Oxidosqualene into parkeol.Under high pressure, the relative enzymatic activity and stability of cyclase inChiridota sp. was higher than that in the shallow-sea holothurianStichopus horrens. The newly cloned OSC of Chiridota sp.provideskey information for the interpretation of the saponin synthesis pathway in deep-sea holothurians.
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Affiliation(s)
- Yanan Huang
- Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Helu Liu
- Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
| | - Yang Zhou
- Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
| | - Zaiqing Lu
- Ocean University of China, Qingdao 266100, China
| | - Yujin Pu
- Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haibin Zhang
- Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China.
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2
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Duschak VG. Major Kinds of Drug Targets in Chagas Disease or American Trypanosomiasis. Curr Drug Targets 2019; 20:1203-1216. [PMID: 31020939 DOI: 10.2174/1389450120666190423160804] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 11/22/2022]
Abstract
American Trypanosomiasis, a parasitic infection commonly named Chagas disease, affects millions of people all over Latin American countries. Presently, the World Health Organization (WHO) predicts that the number of international infected individuals extends to 7 to 8 million, assuming that more than 10,000 deaths occur annually. The transmission of the etiologic agent, Trypanosoma cruzi, through people migrating to non-endemic world nations makes it an emergent disease. The best promising targets for trypanocidal drugs may be classified into three main groups: Group I includes the main molecular targets that are considered among specific enzymes involved in the essential processes for parasite survival, principally Cruzipain, the major antigenic parasite cysteine proteinase. Group II involves biological pathways and their key specific enzymes, such as Sterol biosynthesis pathway, among others, specific antioxidant defense mechanisms, and bioenergetics ones. Group III includes the atypical organelles /structures present in the parasite relevant clinical forms, which are absent or considerably different from those present in mammals and biological processes related to them. These can be considered potential targets to develop drugs with extra effectiveness and fewer secondary effects than the currently used therapeutics. An improved distinction between the host and the parasite targets will help fight against this neglected disease.
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Affiliation(s)
- Vilma G Duschak
- National Council of Scientific and Technical Reasearch (CONICET) Researcher, Area of Protein Biochemistry and Parasite Glycobiology, Research Department, National Institute of Parasitology (INP), "Dr. Mario Fatala Chaben", ANLIS-Malbran, National Health Secretary, Av. Paseo Colon 568, Lab 506, Ciudad Autonoma de Buenos Aires (1063), Buenos Aires, Argentina
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3
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Dahlin P, Srivastava V, Bulone V, McKee LS. The Oxidosqualene Cyclase from the Oomycete Saprolegnia parasitica Synthesizes Lanosterol as a Single Product. Front Microbiol 2016; 7:1802. [PMID: 27881978 PMCID: PMC5101207 DOI: 10.3389/fmicb.2016.01802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 10/27/2016] [Indexed: 11/29/2022] Open
Abstract
The first committed step of sterol biosynthesis is the cyclisation of 2,3-oxidosqualene to form either lanosterol (LA) or cycloartenol (CA). This is catalyzed by an oxidosqualene cyclase (OSC). LA and CA are subsequently converted into various sterols by a series of enzyme reactions. The specificity of the OSC therefore determines the final composition of the end sterols of an organism. Despite the functional importance of OSCs, the determinants of their specificity are not well understood. In sterol-synthesizing oomycetes, recent bioinformatics, and metabolite analysis suggest that LA is produced. However, this catalytic activity has never been experimentally demonstrated. Here, we show that the OSC of the oomycete Saprolegnia parasitica, a severe pathogen of salmonid fish, has an uncommon sequence in a conserved motif important for specificity. We present phylogenetic analysis revealing that this sequence is common to sterol-synthesizing oomycetes, as well as some plants, and hypothesize as to the evolutionary origin of some microbial sequences. We also demonstrate for the first time that a recombinant form of the OSC from S. parasitica produces LA exclusively. Our data pave the way for a detailed structural characterization of the protein and the possible development of specific inhibitors of oomycete OSCs for disease control in aquaculture.
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Affiliation(s)
- Paul Dahlin
- Division of Glycoscience, School of Biotechnology, KTH Royal Institute of TechnologyStockholm, Sweden; Department of Ecology, Environment and Plant Sciences, Stockholm UniversityStockholm, Sweden
| | - Vaibhav Srivastava
- Division of Glycoscience, School of Biotechnology, KTH Royal Institute of Technology Stockholm, Sweden
| | - Vincent Bulone
- Division of Glycoscience, School of Biotechnology, KTH Royal Institute of TechnologyStockholm, Sweden; ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, The University of Adelaide, UrrbraeSA, Australia
| | - Lauren S McKee
- Division of Glycoscience, School of Biotechnology, KTH Royal Institute of TechnologyStockholm, Sweden; Wallenberg Wood Science Centre, KTH Royal Institute of TechnologyStockholm, Sweden
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4
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Identification of compounds with anti-proliferative activity against Trypanosoma brucei brucei strain 427 by a whole cell viability based HTS campaign. PLoS Negl Trop Dis 2012; 6:e1896. [PMID: 23209849 PMCID: PMC3510080 DOI: 10.1371/journal.pntd.0001896] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 09/21/2012] [Indexed: 11/19/2022] Open
Abstract
Human African Trypanosomiasis (HAT) is caused by two trypanosome sub-species, Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Drugs available for the treatment of HAT have significant issues related to difficult administration regimes and limited efficacy across species and disease stages. Hence, there is considerable need to find new alternative and less toxic drugs. An approach to identify starting points for new drug candidates is high throughput screening (HTS) of large compound library collections. We describe the application of an Alamar Blue based, 384-well HTS assay to screen a library of 87,296 compounds against the related trypanosome subspecies, Trypanosoma brucei brucei bloodstream form lister 427. Primary hits identified against T.b. brucei were retested and the IC50 value compounds were estimated for T.b. brucei and a mammalian cell line HEK293, to determine a selectivity index for each compound. The screening campaign identified 205 compounds with greater than 10 times selectivity against T.b. brucei. Cluster analysis of these compounds, taking into account chemical and structural properties required for drug-like compounds, afforded a panel of eight compounds for further biological analysis. These compounds had IC50 values ranging from 0.22 µM to 4 µM with associated selectivity indices ranging from 19 to greater than 345. Further testing against T.b. rhodesiense led to the selection of 6 compounds from 5 new chemical classes with activity against the causative species of HAT, which can be considered potential candidates for HAT early drug discovery. Structure activity relationship (SAR) mining revealed components of those hit compound structures that may be important for biological activity. Four of these compounds have undergone further testing to 1) determine whether they are cidal or static in vitro at the minimum inhibitory concentration (MIC), and 2) estimate the time to kill. Human African Sleeping Sickness (HAT) is a disease caused by sub-species of Trypanosoma. The disease affects developing countries within Africa, mainly occurring in rural regions that lack resources to purchase drugs for treatment. Drugs that are currently available have significant side effects, and treatment regimes are lengthy and not always transferrable to the field. In consideration of these factors, new drugs are urgently needed for the treatment of HAT. To discover compounds suitable for drug discovery, cultured trypanosomes can be tested against libraries of compounds to identify candidates for further biological analysis. We have utilised a 384-well format, Alamar Blue viability assay to screen a large non-proprietary compound collection against Trypanosoma brucei brucei bloodstream form lister 427. The assay was shown to be reproducible, with reference compounds exhibiting activity in agreement with previously published results. Primary screening hits were retested against T.b. brucei and HEK293 mammalian cells in order to assess selectivity against the parasite. Selective hits were characterised by chemical analysis, taking into consideration drug-like properties amenable to further progression. Priority compounds were tested against a panel of protozoan parasites, including Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum. Five new compound classes were discovered that are amenable to progression in the drug discovery process for HAT.
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Urbina JA. Specific chemotherapy of Chagas disease: relevance, current limitations and new approaches. Acta Trop 2010; 115:55-68. [PMID: 19900395 DOI: 10.1016/j.actatropica.2009.10.023] [Citation(s) in RCA: 323] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 10/22/2009] [Accepted: 10/26/2009] [Indexed: 01/31/2023]
Abstract
A critical review of the development of specific chemotherapeutic approaches for the management of American Trypanosomiasis or Chagas disease is presented, including controversies on the pathogenesis of the disease, the initial efforts that led to the development of currently available drugs (nifurtimox and benznidazole), limitations of these therapies and novel approaches for the development of anti-Trypanosoma cruzi drugs, based on our growing understanding of the biology of this parasite. Among the later, the most promising approaches are ergosterol biosynthesis inhibitors such as posaconazole and ravuconazole, poised to enter clinical trials for chronic Chagas disease in the short term; inhibitors of cruzipain, the main cysteine protease of T. cruzi, essential for its survival and proliferation in vitro and in vivo; bisphosphonates, metabolic stable pyrophosphate analogs that have trypanocidal activity through the inhibition of the parasite's farnesyl-pyrophosphate synthase or hexokinase; inhibitors of trypanothione synthesis and redox metabolism and inhibitors of hypoxanthine-guanine phosphoribosyl-transferase, an essential enzyme for purine salvage in T. cruzi and related organisms. Finally, the economic and political challenges faced by development of drugs for the treatment of neglected tropical diseases, which afflict almost exclusively poor populations in developing countries, are analyzed and recent potential solutions for this conundrum are discussed.
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6
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Urbina JA. Ergosterol biosynthesis and drug development for Chagas disease. Mem Inst Oswaldo Cruz 2010; 104 Suppl 1:311-8. [PMID: 19753490 DOI: 10.1590/s0074-02762009000900041] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 05/18/2009] [Indexed: 12/13/2022] Open
Abstract
This article presents an overview of the currently available drugs nifurtimox (NFX) and benznidazole (BZN) used against Trypanosoma cruzi, the aetiological agent of Chagas disease; herein we discuss their limitations along with potential alternatives with a focus on ergosterol biosynthesis inhibitors (EBI). These compounds are currently the most advanced candidates for new anti-T. cruzi agents given that they block de novo production of 24-alkyl-sterols, which are essential for parasite survival and cannot be replaced by a host's own cholesterol. Among these compounds, new triazole derivatives that inhibit the parasite's C14alpha sterol demethylase are the most promising, as they have been shown to have curative activity in murine models of acute and chronic Chagas disease and are active against NFX and BZN-resistant T. cruzi strains; among this class of compounds, posaconazole (Schering-Plough Research Institute) and ravuconazole (Eisai Company) are poised for clinical trials in Chagas disease patients in the short term. Other T. cruzi-specific EBI, with in vitro and in vivo potency, include squalene synthase, lanosterol synthase and squalene epoxidase-inhibitors as well as compounds with dual mechanisms of action (ergosterol biosynthesis inhibition and free radical generation), but they are less advanced in their development process. The main putative advantages of EBI over currently available therapies include their higher potency and selectivity in both acute and chronic infections, activity against NFX and BZN-resistant T. cruzi strains, and much better tolerability and safety profiles. Limitations may include complexity and cost of manufacture of the new compounds. As for any new drug, such compounds will require extensive clinical testing before being introduced for clinical use, and the complexity of such studies, particularly in chronic patients, will be compounded by the current limitations in the verification of true parasitological cures for T. cruzi infections.
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Affiliation(s)
- Julio A Urbina
- Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
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7
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Soeiro MNC, de Castro SL. Trypanosoma cruzitargets for new chemotherapeutic approaches. Expert Opin Ther Targets 2008; 13:105-21. [DOI: 10.1517/14728220802623881] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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8
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CYP51: A major drug target in the cytochrome P450 superfamily. Lipids 2008; 43:1117-25. [PMID: 18769951 DOI: 10.1007/s11745-008-3225-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 08/08/2008] [Indexed: 10/21/2022]
Abstract
The cytochrome P540 (CYP) superfamily currently includes about 9000 proteins forming more than 800 families. The enzymes catalyze monooxygenation of a vast array of compounds and play essentially two roles. They provide biodefense (detoxification of xenobiotics, antibiotic production) and participate in biosynthesis of important endogenous molecules, particularly steroids. Based on these two roles, sterol 14/*alpha*/-demethylases (CYP51) belong to the second group of P450s. The CYP51 family, however, is very special as its members preserve strict functional conservation in enzyme activity in all biological kingdoms. At amino acid identity across the kingdoms as low as 25-30%, they all catalyze essentially the same three-step reaction of oxidative removal of the 14/*alpha*/-methyl group from the lanostane frame. This reaction is the required step in sterol biosynthesis of pathogenic microbes. We have shown that specific inhibition of protozoan CYP51 can potentially provide treatment for human trypanosomiases. Three sets of CYP51 inhibitors tested in vitro and in trypanosomal cells in this study include azoles [best results being 50% cell growth inhibition at <1 and at 1.3 muM for Trypanosoma cruzi (TC) and Trypanosoma brucei (TB), respectively], non-azole compounds (50% TC cell growth inhibition at 5 microM) and substrate analogs of the 14/*alpha*/-demethylase reaction. 32-Methylene cyclopropyl lanost-7-enol exhibited selectivity toward TC with 50% cell growth inhibition at 3 microM.
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9
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Oliaro-Bosso S, Viola F, Taramino S, Tagliapietra S, Barge A, Cravotto G, Balliano G. Inhibitory Effect of Umbelliferone Aminoalkyl Derivatives on Oxidosqualene Cyclases fromS. cerevisiae,T. cruzi,P. carinii,H. sapiens, andA. thaliana: a Structure–Activity Study. ChemMedChem 2007; 2:226-33. [PMID: 17154325 DOI: 10.1002/cmdc.200600234] [Citation(s) in RCA: 14] [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
Eighteen coumarin derivatives were tested as inhibitors of oxidosqualene cyclases (OSCs) from Saccharomyces cerevisiae, Trypanosoma cruzi, Pneumocystis carinii, Homo sapiens, and Arabidopsis thaliana, all expressed in an OSC-defective strain of S. cerevisiae.35 All the compounds have an aminoalkyl chain bound to an aromatic nucleus; unconventional synthetic procedures (microwave- and ultrasound-promoted reactions) were successfully used to prepare some of them. The most interesting structure-dependent difference in inhibitory activities was observed with an N-oxide group replacement of the tertiary amino group at the end of the side chain. An interesting species specificity also emerged: T. cruzi OSC was the least sensitive enzyme; P. carinii and A. thaliana OSCs were the most sensitive. The remarkable activities of three compounds on the T. cruzi enzyme and of five of them on the P. carinii enzyme suggest the present series as a promising compound family for the development of novel antiparasitic agents.
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Affiliation(s)
- Simonetta Oliaro-Bosso
- Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, via P. Giuria 9, 10125 Turin, Italy
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10
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Galli U, Oliaro-Bosso S, Taramino S, Venegoni S, Pastore E, Tron GC, Balliano G, Viola F, Sorba G. Design, synthesis, and biological evaluation of new (2E,6E)-10-(dimethylamino)-3,7-dimethyl-2,6-decadien-1-ol ethers as inhibitors of human and Trypanosoma cruzi oxidosqualene cyclase. Bioorg Med Chem Lett 2007; 17:220-4. [PMID: 17027267 DOI: 10.1016/j.bmcl.2006.09.058] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 09/15/2006] [Accepted: 09/20/2006] [Indexed: 11/16/2022]
Abstract
New dimethylamino truncated squalene ether derivatives containing a different aromatic moiety (phenyl, naphthyl, and biphenyl) or a simple alkyl (n-hexylic) group were synthesized as inhibitors of the oxidosqualene cyclase (OSC) and of the sterol biosynthetic pathway. The activity against human OSC was compared with the activity against the OSCs of pathogenic organisms such as Pneumocystis carinii and Trypanosoma cruzi. The phenyl derivative was the most potent inhibitor of T. cruzi OSC.
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Affiliation(s)
- Ubaldina Galli
- Dipartimento di Scienze Chimiche, Alimentari, Farmaceutiche e Farmacologiche and Drug and Food Biotechnology Center, Università degli Studi del Piemonte Orientale A. Avogadro, Via Bovio 6, 28100 Novara, Italy.
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11
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Kolesnikova MD, Xiong Q, Lodeiro S, Hua L, Matsuda SPT. Lanosterol biosynthesis in plants. Arch Biochem Biophys 2006; 447:87-95. [PMID: 16445886 DOI: 10.1016/j.abb.2005.12.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Revised: 12/21/2005] [Accepted: 12/22/2005] [Indexed: 10/25/2022]
Abstract
Plants biosynthesize sterols from cycloartenol using a pathway distinct from the animal and fungal route through lanosterol. Described herein are genome-mining experiments revealing that Arabidopsis encodes, in addition to cycloartenol synthase, an accurate lanosterol synthase (LSS)--the first example of lanosterol synthases cloned from a plant. The coexistence of cycloartenol synthase and lanosterol synthase implies specific roles for both cyclopropyl and conventional sterols in plants. Phylogenetic reconstructions reveal that lanosterol synthases are broadly distributed in eudicots but evolved independently from those in animals and fungi. Novel catalytic motifs establish that plant lanosterol synthases comprise a third catalytically distinct class of lanosterol synthase.
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Affiliation(s)
- Mariya D Kolesnikova
- Department of Chemistry, Rice University, 6100 S. Main Street, Houston, TX 77005, USA
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12
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Zhou W, Lepesheva GI, Waterman MR, Nes WD. Mechanistic analysis of a multiple product sterol methyltransferase implicated in ergosterol biosynthesis in Trypanosoma brucei. J Biol Chem 2006; 281:6290-6. [PMID: 16414960 DOI: 10.1074/jbc.m511749200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sterol methyltransferase (SMT) plays a key role in sterol biosynthesis in different pathogenic organisms by setting the pattern of the side chain structure of the final product. This catalyst, absent in humans, provides critical pathway-specific enzymatic steps in the production of ergosterol in fungi or phytosterols in plants. The new SMT gene was isolated from Trypanosoma brucei genomic DNA and cloned into an Escherichia coli expression system. The recombinant SMT was purified to homogeneity to give a band at 40.0 kDa upon SDS-PAGE and showed a tetrameric subunit organization by gel chromatography. It has a pH optimum of 7.5, an apparent kcat value of 0.01 s(-1), and a Km of 47 +/- 4 microm for zymosterol. The products of the reaction were a mixture of C24-monoalkylated sterols, ergosta-8,24 (25)-dienol, ergosta-8,25 (27)-dienol, and ergosta-8,24 (28)-dienol (fecosterol), and an unusual double C24-alkylated sterol, 24,24-dimethyl ergosta-8,25 (27)-dienol, typically found in plants. Inhibitory profile studies with 25-azalanosterol (Ki value of 39 nm) or 24(R,S), 25-epiminolanosterol (Ki value of 49 nm), ergosterol (Ki value of 27 microm) and 26,27-dehydrozymosterol (Ki and kinact values of 29 microm and 0.26 min(-1), respectively) and data showing zymosterol as the preferred acceptor strongly suggest that the protozoan SMT has an active site topography combining properties of the SMT1 from plants and yeast (37-47% identity). The enzymatic activation of this and other SMTs reveals that the catalytic requirements for the C-methyl reaction are remarkably versatile, whereas the inhibition studies provide a powerful approach to rational design of new anti-sleeping sickness chemotherapeutic drugs.
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Affiliation(s)
- Wenxu Zhou
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1064, USA
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Oliaro-Bosso S, Ceruti M, Balliano G, Milla P, Rocco F, Viola F. Analogs of squalene and oxidosqualene inhibit oxidosqualene cyclase of Trypanosoma cruzi expressed in Saccharomyces cerevisiae. Lipids 2005; 40:1257-62. [PMID: 16477810 DOI: 10.1007/s11745-005-1493-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Recently, a number of inhibitors of the enzyme oxidosqualene cyclase (OSC; EC 5.4.99.7), a key enzyme in sterol biosynthesis, were shown to inhibit in mammalian cells the multiplication of Trypanosoma cruzi, the parasite agent of Chagas' disease. The gene coding for the OSC of T. cruzi has been cloned and expressed in Saccharomyces cerevisiae. The expression in yeast cells could be a safe and easy model for studying the activity and the selectivity of the potential inhibitors of T. cruzi OSC. Using a homogenate of S. cerevisiae cells expressing T. cruzi OSC, we have tested 19 inhibitors: aza, methylidene, vinyl sulfide, and conjugated vinyl sulfide derivatives of oxidosqualene and squalene, selected as representative of different classes of substrate analog inhibitors of OSC. The IC50 values of inhibition (the compound concentration at which the enzyme is inhibited by 50%) are compared with the values obtained using OSC of pig liver and S. cerevisiae. Many inhibitors of pig liver and S. cerevisiae OSC show comparable IC50 for T. cruzi OSC, but some phenylthiovinyl derivatives are 10-100 times more effective on the T. cruzi enzyme than on the pig or S. cerevisiae enzymes. The expression of proteins of pathogenic organisms in yeast seems very promising for preliminary screening of compounds that have potential therapeutic activity.
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Affiliation(s)
- Simonetta Oliaro-Bosso
- Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, 10125 Turin, Italy
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14
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Lodeiro S, Schulz-Gasch T, Matsuda SPT. Enzyme Redesign: Two Mutations Cooperate to Convert Cycloartenol Synthase into an Accurate Lanosterol Synthase. J Am Chem Soc 2005; 127:14132-3. [PMID: 16218577 DOI: 10.1021/ja053791j] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Efforts to modify the catalytic specificity of enzymes consistently show that it is easier to broaden the substrate or product specificity of an accurate enzyme than to restrict the selectivity of one that is promiscuous. Described herein are experiments in which cycloartenol synthase was redesigned to become a highly accurate lanosterol synthase. Several single mutants have been described that modify the catalytic specificity of cycloartenol to form some lanosterol. Modeling studies were undertaken to identify combinations of mutations that cooperate to decrease the formation of products other than lanosterol. A double mutant was constructed and characterized and was shown to cyclize oxidosqualene accurately to lanosterol (99%). This catalytic change entailed both relocating polarity with a His477Asn mutation and modifying steric constraints with an Ile481Val mutation.
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Affiliation(s)
- Silvia Lodeiro
- Department of Chemistry and Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
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15
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Urbina JA. New chemotherapeutic approaches for the treatment of Chagas disease (American Trypanosomiasis). Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.13.5.661] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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16
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Wu TK, Chang CH. Enzymatic Formation of Multiple Triterpenes by Mutation of Tyrosine 510 of the Oxidosqualene-Lanosterol Cyclase from Saccharomyces cerevisiae. Chembiochem 2004; 5:1712-5. [PMID: 15508118 DOI: 10.1002/cbic.200400079] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Tung-Kung Wu
- Department of Biological Science and Technology, Center for Interdisciplinary Molecular Science, National Chiao Tung University, 300, Hsin-Chu, Taiwan, Republic of China.
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17
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Oliaro-Bosso S, Viola F, Matsuda S, Cravotto G, Tagliapietra S, Balliano G. Umbelliferone aminoalkyl derivatives as inhibitors of oxidosqualene cyclases from Saccharomyces cerevisiae, Tripanosoma cruzi, and Pneumocystis carinii. Lipids 2004; 39:1007-12. [PMID: 15691023 DOI: 10.1007/s11745-004-1323-2] [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] [Indexed: 11/26/2022]
Abstract
A series of umbelliferone aminoalkyl derivatives, previously studied as inhibitors of squalene-hopene cyclase, were tested as inhibitors of yeast (Saccharomyces cerevisiae) oxidosqualene cyclase (OSC) and OSC from Trypanosoma cruzi and Pneumocystis carinii expressed in yeast. Enzymes from these pathogens were included in this study to provide a preliminary screening for antiparasitic activity. Tests were carried out both on cell homogenates incubated with radiolabeled oxidosqualene and on spheroplasts incubated with radiolabeled acetate. Derivatives bearing a methylallylamino group were the most effective on all of the three enzymes. The P. carinii enzyme was the most susceptible to the action of the inhibitors, with IC50 values for almost all of them ranging from 0.1 to 1 microM. The T. cruzi enzyme was appreciably inhibited (IC50 4-5 microM) only by derivatives bearing a methylallylaminoalkyl flexible chain. Results identify a particularly promising new family of OSC inhibitors, for the development of novel antiparasitic agents.
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Affiliation(s)
- Simonetta Oliaro-Bosso
- Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, 10125 Turin, Italy
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18
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Abstract
The triterpenoids are a large group of natural products derived from C(30) precursors. Nearly 200 different triterpene skeletons are known from natural sources or enzymatic reactions that are structurally consistent with being cyclization products of squalene, oxidosqualene, or bis-oxidosqualene. This review categorizes each of these structures and provides mechanisms for their formation.
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Affiliation(s)
- Ran Xu
- Department of Chemistry, Rice University, 6100 S Main Street, Houston, TX 77005, USA
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19
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Abstract
In recent years, the impressive development of molecular genetics tools, the sequencing of the Arabidopsis thaliana genome, the availability of DNA or transposon tagged mutants, and the multiple possibilities offered by stable transformation with DNA in sense and antisense orientation have enabled the application of a strategy of gain or loss of function to study the sterol biosynthesis pathway. Here we describe the results obtained with these techniques. The results essentially confirm data obtained previously with sterol biosynthesis inhibitors (SBIs) and enable the precise dissection of biosynthetic pathways. We discuss the advantages and disadvantages of molecular genetics techniques as applied to sterol metabolism. The greater selectivity of these techniques constitutes an invaluable advantage and has led to the discovery of a role for sterols in plant development.
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Affiliation(s)
- Pierre Benveniste
- Institut de Biologie Moleculaire des Plantes, Departement Biogenese et Fonctions des Isoprenoides, UPR-CNRS 2357, 28 rue Goethe, 67083 Strasbourg, France.
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20
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Hinshaw JC, Suh DY, Garnier P, Buckner FS, Eastman RT, Matsuda SPT, Joubert BM, Coppens I, Joiner KA, Merali S, Nash TE, Prestwich GD. Oxidosqualene cyclase inhibitors as antimicrobial agents. J Med Chem 2003; 46:4240-3. [PMID: 13678402 DOI: 10.1021/jm034126t] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Small-molecule oxidosqualene cyclase (OSC) inhibitors were found to be effective in assays against cloned OSC-like enzymes from human pathogens. A combinatorial library was prepared and used to identify lead compounds that inhibit the growth of Trypanosoma cruzi, Leishmania mexicana amazonensis, and Pneumocystis carinii in culture. Selectivity for the microorganisms in preference to mammalian cells was observed.
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Affiliation(s)
- Jerald C Hinshaw
- Department of Medicinal Chemistry, University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108-1257, USA
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21
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Segura MJR, Jackson BE, Matsuda SPT. Mutagenesis approaches to deduce structure-function relationships in terpene synthases. Nat Prod Rep 2003; 20:304-17. [PMID: 12828369 DOI: 10.1039/b008338k] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review highlights mutagenesis studies of terpene synthases, specifically sesquiterpene synthases and oxidosqualene cyclases. Mutagenesis studies of these enzymes have provided mechanistic insights, structure-function relationships for specific enzymatic residues, novel terpene structures and enzymes with novel activities. The literature through 2002 is reviewed and 113 references cited.
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22
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The C- and D-ring problems of sterol biosynthesis: hydride shift versus carboncarbon bond migration due to conformational changes controlled by counteranion. Tetrahedron Lett 2003. [DOI: 10.1016/s0040-4039(03)00611-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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23
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Rocco F, Bosso SO, Viola F, Milla P, Roma G, Grossi G, Ceruti M. Conjugated methyl sulfide and phenyl sulfide derivatives of oxidosqualene as inhibitors of oxidosqualene and squalene-hopene cyclases. Lipids 2003; 38:201-7. [PMID: 12784859 DOI: 10.1007/s11745-003-1052-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Various (1E,3E)- and (1Z,3E)-conjugated methylthio derivatives of oxidosqualene (OS) and conjugated and non-conjugated phenylthio derivatives of OS were obtained. These compounds, designed as inhibitors of pig liver and Saccharomyces cerevisiae 2,3-oxidosqualene-lanosterol cyclases (OSC) (EC 5.4.99.7) and of Alicyclobacillus acidocaldarius squalene-hopene cyclase (SHC) (EC 5.4.99.-), contain the reactive function adjacent to carbons involved in the formation of the third and the fourth cycle during OS cyclization. All the new compounds are inhibitors of OSC and SHC, with various degrees of selectivity. The conjugated methylthio derivatives behaved as potent inhibitors of S. cerevisiae OSC, whereas most of the phenylthio derivatives were especially active toward SHC.
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Affiliation(s)
- Flavio Rocco
- Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, 10125 Torino, Italy
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Segura MJR, Lodeiro S, Meyer MM, Patel AJ, Matsuda SPT. Directed evolution experiments reveal mutations at cycloartenol synthase residue His477 that dramatically alter catalysis. Org Lett 2002; 4:4459-62. [PMID: 12465912 DOI: 10.1021/ol0269897] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Cycloartenol synthase cyclizes and rearranges oxidosqualene to the protosteryl cation and then specifically deprotonates from C-19. To identify mutants that deprotonate differently, randomly generated mutant cycloartenol synthases were selected in a yeast lanosterol synthase mutant. A novel His477Asn mutant was uncovered that produces 88% lanosterol and 12% parkeol. The His477Gln mutant produces 73% parkeol, 22% lanosterol, and 5% Delta(7)-lanosterol. These are the most accurate lanosterol synthase and parkeol synthase that have been generated by mutagenesis.
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Milla P, Viola F, Oliaro Bosso S, Rocco F, Cattel L, Joubert BM, LeClair RJ, Matsuda SPT, Balliano G. Subcellular localization of oxidosqualene cyclases from Arabidopsis thaliana, Trypanosoma cruzi, and Pneumocystis carinii expressed in yeast. Lipids 2002; 37:1171-6. [PMID: 12617471 DOI: 10.1007/s11745-002-1017-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cycloartenol synthase from Arabidopsis thaliana and lanosterol synthase from Trypanosoma cruzi and Pneumocystis carinii were expressed in yeast, and their subcellular distribution in the expressing cells was compared. Determination of enzymatic (oxidosqualene cyclase, OSC) activity and SDS-PAGE analysis of subcellular fractions proved that enzymes from T. cruzi and A. thaliana have high affinity for lipid particles, a subcellular compartment rich in triacylglycerols, and steryl esters, harboring several enzymes of lipid metabolism. In lipid particles of strains expressing the P. carinii enzyme, neither OSC activity nor the electrophoretic band at the appropriate M.W. were detected. Microsomes from the three expressing strains retained some OSC activity. Affinity of enzymes from A. thaliana and T. cruzi for lipid particles is similar to that of OSC of Saccharomyces cerevisiae, which is mainly located in this compartment. A different distribution of OSC in yeast cells suggests that they differ in some structural features critical for the interaction with the surface of lipid particles. Computer analysis supports the hypothesis of the structural difference since OSC from S. cerevisiae, A. thaliana, and T. cruzi lack or contain only one transmembrane spanning domain (a structural feature that makes a protein poorly inclined to associate with lipid particles), whereas OSC from P. carinii possesses six transmembrane domains. In the strain expressing cycloartenol synthase from A. thaliana, the accumulation of lipid particles largely exceeded that of the other strains.
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Affiliation(s)
- P Milla
- Università degli Studi di Torino, Dipartimento di Scienza e Tecnologia del Farmaco, 1-10125 Torino, Italy
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26
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Meyer MM, Xu R, Matsuda SPT. Directed evolution to generate cycloartenol synthase mutants that produce lanosterol. Org Lett 2002; 4:1395-8. [PMID: 11950371 DOI: 10.1021/ol0257225] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cycloartenol synthase converts oxidosqualene to cycloartenol, a pentacyclic isomer of the animal and fungal sterol precursor lanosterol. We used directed evolution to find cycloartenol synthase residues that affect cyclopropyl ring formation, selecting randomly generated cycloartenol synthase mutants for their ability to genetically complement a yeast strain lacking lanosterol synthase. To increase the likelihood of finding novel mutations, the little-studied Dictyostelium discoideum cycloartenol synthase was used for the mutagenesis. Several catalytically important residues were identified. [reaction: see text]
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Affiliation(s)
- Michelle M Meyer
- Department of Chemistry, Rice University, 6100 South Main Street, Houston, Texas 77005, USA
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Vaena de Avalos S, Blader IJ, Fisher M, Boothroyd JC, Burleigh BA. Immediate/early response to Trypanosoma cruzi infection involves minimal modulation of host cell transcription. J Biol Chem 2002; 277:639-44. [PMID: 11668183 DOI: 10.1074/jbc.m109037200] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Host cell infection by the intracellular pathogen, Trypanosoma cruzi, involves activation of signaling pathways, cytoskeletal reorganization, and targeted recruitment of host cell lysosomes. To determine the consequences of T. cruzi invasion on host cell gene expression, high density microarrays consisting of approximately 27,000 human cDNAs were hybridized with fluorescent probes generated from T. cruzi-infected human fibroblasts (HFF) at early time points following infection (2-24 h). Surprisingly, no genes were induced > or =2-fold in HFF between 2 and 6 h post-infection (hpi) in repeated experiments while immediate repression of six host cell transcripts was observed. A significant increase in transcript abundance for 106 host cell genes was observed at 24 hpi. Among the most highly induced is a set of interferon-stimulated genes, indicative of a type I interferon (IFN) response to T. cruzi. In support of this, T. cruzi-infected fibroblasts begin to secrete IFNbeta at 18 hpi following the induction of IFNbeta transcripts. As compared with global transcriptional responses evoked by other intracellular pathogens, T. cruzi is a stealth parasite that elicits few changes in host cell transcription during the initiation of infection.
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Affiliation(s)
- Silvia Vaena de Avalos
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA
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Abe I, Naito K, Takagi Y, Noguchi H. Molecular cloning, expression, and site-directed mutations of oxidosqualene cyclase from Cephalosporium caerulens. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1522:67-73. [PMID: 11750056 DOI: 10.1016/s0167-4781(01)00307-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A cDNA for oxidosqualene:lanosterol cyclase (OSLC) was cloned and sequenced from the fungus Cephalosporium caerulens, that produces a steroidal antibiotic, helvolic acid. A 2280 bp open reading frame encoded an M(r) 87078 protein with 760 amino acids. The cDNA was functionally expressed in the OSLC-deficient mutant GIL77 strain of Saccharomyces cerevisiae. A truncated recombinant enzyme (Delta49N) starting from the second methionine (M50) residue was completely inactive, suggesting that ca. 30 additional hydrophilic amino acid residues at the N-terminal are essential for the folding of the enzyme. Furthermore, the active site residues, H234 and D456 (numbering in S. cerevisiae OSLC), were chosen for site-directed mutagenesis experiments; H234E, H234Y, H234F, D456E, D456N, and D456H mutants were inactive, while H234W and H234K mutants retained lanosterol-forming activity.
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Affiliation(s)
- I Abe
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, 422-8526, Shizuoka, Japan.
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