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Guo KX, Bai Y, Ren HN, Sun XY, Song YY, Liu RD, Long SR, Zhang X, Jiang P, Wang ZQ, Cui J. Characterization of a Trichinella spiralis aminopeptidase and its participation in invasion, development and fecundity. Vet Res 2020; 51:78. [PMID: 32539772 PMCID: PMC7296678 DOI: 10.1186/s13567-020-00805-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/11/2020] [Indexed: 02/08/2023] Open
Abstract
A Trichinella spiralis aminopeptidase (TsAP) has been identified in intestinal infectious larvae (IIL) and adult worms (AW), but its biological function in the T. spiralis life cycle is unknown. The aim of this study was to characterize TsAP and ascertain its functions in the invasion, development and fecundity of T. spiralis. Recombinant TsAP (rTsAP) was expressed and purified. rTsAP has strong immunogenicity. qPCR and western blotting show that TsAP was transcribed and expressed at all T. spiralis lifecycle stages, but the expression level of TsAP mRNA and proteins at IIL and AW stages was obviously higher than those in muscle larvae (ML) and newborn larvae (NBL). The IFT results reveal that TsAP was principally located at the cuticle and the intrauterine embryos of this nematode. rTsAP had the enzymatic activity of natural aminopeptidase to hydrolyze the substrate Leu-pNA with an optimal temperature of 50 °C and optimal pH of 8.0. rTsAP promoted the larval penetration into intestinal epithelial cells, whereas anti-rTsAP antibodies suppressed the larval intrusion; the promotion and suppression was dose-dependently related to rTsAP or anti-rTsAP antibodies. TsAP protein expression level and enzymatic activity were reduced by 50.90 and 49.72% through silencing of the TsAP gene by specific siRNA 842. Intestinal AW and muscle larval burdens, worm length and female reproductive capacity were significantly declined in mice infected with siRNA-transfected ML compared to the control siRNA and PBS group. These results indicate that TsAP participates in the invasion, development and fecundity of T. spiralis and it might be a candidate target for anti-Trichinella vaccines.
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Affiliation(s)
- Kai Xia Guo
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Ying Bai
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Hua Nan Ren
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Xiang Yuan Sun
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Yan Yan Song
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Ruo Dan Liu
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Shao Rong Long
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Xi Zhang
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Peng Jiang
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Zhong Quan Wang
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
| | - Jing Cui
- Department of Parasitology, Medical College, Zhengzhou University, Zhengzhou, 450052 China
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Mohandas N, Young ND, Jabbar A, Korhonen PK, Koehler AV, Hall RS, Hu M, Hofmann A, Gasser RB. The complement of family M1 aminopeptidases of Haemonchus contortus--Biotechnological implications. Biotechnol Adv 2015; 34:65-76. [PMID: 26597954 DOI: 10.1016/j.biotechadv.2015.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 10/04/2015] [Accepted: 10/10/2015] [Indexed: 01/03/2023]
Abstract
Although substantial research has been focused on the 'hidden antigen' H11 of Haemonchus contortus as a vaccine against haemonchosis in small ruminants, little is know about this and related aminopeptidases. In the present article, we reviewed genomic and transcriptomic data sets to define, for the first time, the complement of aminopeptidases (designated Hc-AP-1 to Hc-AP-13) of the family M1 with homologues in Caenorhabditis elegans, characterised by zinc-binding (HEXXH) and exo-peptidase (GAMEN) motifs. The three previously published H11 isoforms (accession nos. X94187, FJ481146 and AJ249941) had most sequence similarity to Hc-AP-2 and Hc-AP-8, whereas unpublished isoforms (accession nos. AJ249942 and AJ311316) were both most similar to Hc-AP-3. The aminopeptidases characterised here had homologues in C. elegans. Hc-AP-1 to Hc-AP-8 were most similar in amino acid sequence (28-41%) to C. elegans T07F10.1; Hc-AP-9 and Hc-AP-10 to C. elegans PAM-1 (isoform b) (53-54% similar); Hc-AP-11 and Hc-AP-12 to C. elegans AC3.5 and Y67D8C.9 (26% and 50% similar, respectively); and Hc-AP-13 to C. elegans C42C1.11 and ZC416.6 (50-58% similar). Comparative analysis suggested that Hc-AP-1 to Hc-AP-8 play roles in digestion, metabolite excretion, neuropeptide processing and/or osmotic regulation, with Hc-AP-4 and Hc-AP-7 having male-specific functional roles. The analysis also indicated that Hc-AP-9 and Hc-AP-10 might be involved in the degradation of cyclin (B3) and required to complete meiosis. Hc-AP-11 represents a leucyl/cystinyl aminopeptidase, predicted to have metallopeptidase and zinc ion binding activity, whereas Hc-AP-12 likely encodes an aminopeptidase Q homologue also with these activities and a possible role in gonad function. Finally, Hc-AP-13 is predicted to encode an aminopeptidase AP-1 homologue of C. elegans with hydrolase activity, suggested to operate, possibly synergistically with a PEPT-1 ortholog, as an oligopeptide transporter in the gut for protein uptake and normal development and/or reproduction of the worm. An appraisal of structure-based amino acid sequence alignments revealed that all conceptually translated Hc-AP proteins, with the exception of Hc-AP-12, adopt a topology similar to those observed for the two subgroups of mammalian M1 aminopeptidases, which possess either three (I, II and IV) or four (I-IV) domains. In contrast, Hc-AP-12 lacks the N-terminal domain (I), but possesses a substantially expanded domain III. Although further work needs to be done to assess amino acid sequence conservation of the different aminopeptidases among individual worms within and among H. contortus populations, we hope that these insights will support future localisation, structural and functional studies of these molecules in H. contortus as well as facilitate future assessments of a recombinant subunit or cocktail vaccine against haemonchosis.
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Affiliation(s)
- Namitha Mohandas
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Neil D Young
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Abdul Jabbar
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Pasi K Korhonen
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Anson V Koehler
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Ross S Hall
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Min Hu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Andreas Hofmann
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia; Structural Chemistry Program, Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland 4111, Australia.
| | - Robin B Gasser
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia; State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
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Balakrishnan R, Harris MA, Huntley R, Van Auken K, Cherry JM. A guide to best practices for Gene Ontology (GO) manual annotation. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2013; 2013:bat054. [PMID: 23842463 PMCID: PMC3706743 DOI: 10.1093/database/bat054] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The Gene Ontology Consortium (GOC) is a community-based bioinformatics project that classifies gene product function through the use of structured controlled vocabularies. A fundamental application of the Gene Ontology (GO) is in the creation of gene product annotations, evidence-based associations between GO definitions and experimental or sequence-based analysis. Currently, the GOC disseminates 126 million annotations covering >374 000 species including all the kingdoms of life. This number includes two classes of GO annotations: those created manually by experienced biocurators reviewing the literature or by examination of biological data (1.1 million annotations covering 2226 species) and those generated computationally via automated methods. As manual annotations are often used to propagate functional predictions between related proteins within and between genomes, it is critical to provide accurate consistent manual annotations. Toward this goal, we present here the conventions defined by the GOC for the creation of manual annotation. This guide represents the best practices for manual annotation as established by the GOC project over the past 12 years. We hope this guide will encourage research communities to annotate gene products of their interest to enhance the corpus of GO annotations available to all. Database URL:http://www.geneontology.org
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Affiliation(s)
- Rama Balakrishnan
- Saccharomyces Genome Database, Department of Genetics, Stanford University, 300 Pasteur Drive, MC-5477 Stanford, CA 94305, USA
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4
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Helgstrand C, Hasan M, Uysal H, Haeggström JZ, Thunnissen MMGM. A leukotriene A4 hydrolase-related aminopeptidase from yeast undergoes induced fit upon inhibitor binding. J Mol Biol 2010; 406:120-34. [PMID: 21146536 DOI: 10.1016/j.jmb.2010.11.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 11/24/2010] [Accepted: 11/30/2010] [Indexed: 01/24/2023]
Abstract
Vertebrate leukotriene A(4) hydrolases are bifunctional zinc metalloenzymes with an epoxide hydrolase and an aminopeptidase activity. In contrast, highly homologous enzymes from lower organisms only have the aminopeptidase activity. From sequence comparisons, it is not clear why this difference occurs. In order to obtain more information on the evolutionary relationship between these enzymes and their activities, the structure of a closely related leucine aminopeptidase from Saccharomyces cerevisiae that only shows a very low epoxide hydrolase activity was determined. To investigate the molecular architecture of the active site, the structures of both the native protein and the protein in complex with the aminopeptidase inhibitor bestatin were solved. These structures show a more spacious active site, and the protected cavity in which the labile substrate leukotriene A(4) is bound in the human enzyme is partially obstructed and in other parts is more solvent accessible. Furthermore, the enzyme undergoes induced fit upon binding of the inhibitor bestatin, leading to a movement of the C-terminal domain. The main triggers for the domain movement are a conformational change of Tyr312 and a subtle change in backbone conformation of the PYGAMEN fingerprint region for peptide substrate recognition. This leads to a change in the hydrogen-bonding network pulling the C-terminal domain into a different position. Inasmuch as bestatin is a structural analogue of a leucyl dipeptide and may be regarded as a transition state mimic, our results imply that the enzyme undergoes induced fit during substrate binding and turnover.
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Affiliation(s)
- Charlotte Helgstrand
- Centre of Molecular Protein Science, Lund University, Getingevägen 60, SE 22100 Lund, Sweden
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5
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Heckmann LH, Sibly RM, Timmermans MJ, Callaghan A. Outlining eicosanoid biosynthesis in the crustacean Daphnia. Front Zool 2008; 5:11. [PMID: 18625039 PMCID: PMC2483973 DOI: 10.1186/1742-9994-5-11] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 07/14/2008] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Eicosanoids are biologically active, oxygenated metabolites of three C20 polyunsaturated fatty acids. They act as signalling molecules within the autocrine or paracrine system in both vertebrates and invertebrates mainly functioning as important mediators in reproduction, the immune system and ion transport. The biosynthesis of eicosanoids has been intensively studied in mammals and it is known that they are synthesised from the fatty acid, arachidonic acid, through either the cyclooxygenase (COX) pathway; the lipoxygenase (LOX) pathway; or the cytochrome P450 epoxygenase pathway. However, little is still known about the synthesis and structure of the pathway in invertebrates. RESULTS Here, we show transcriptomic evidence from Daphnia magna (Crustacea: Branchiopoda) together with a bioinformatic analysis of the D. pulex genome providing insight on the role of eicosanoids in these crustaceans as well as outlining a putative pathway of eicosanoid biosynthesis. Daphnia appear only to have one copy of the gene encoding the key enzyme COX, and phylogenetic analysis reveals that the predicted protein sequence of Daphnia COX clusters with other invertebrates. There is no current evidence of an epoxygenase pathway in Daphnia; however, LOX products are most certainly synthesised in daphnids. CONCLUSION We have outlined the structure of eicosanoid biosynthesis in Daphnia, a key genus in freshwater ecosystems. Improved knowledge of the function and synthesis of eicosanoids in Daphnia and other invertebrates could have important implications for several areas within ecology. This provisional overview of daphnid eicosanoid biosynthesis provides a guide on where to focus future research activities in this area.
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Affiliation(s)
- Lars-Henrik Heckmann
- University of Reading, School of Biological Sciences, Environmental Biology, PO Box 68, Reading, RG6 6BX, UK.
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6
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Bourgeois AC, Koski KG, Scott ME. Comparative Sensitivity of Feeding and Nonfeeding Stages of Heligmosomoides bakeri (Nematoda) to Boron. COMP PARASITOL 2007. [DOI: 10.1654/4275.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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7
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Tholander F, Kull F, Ohlson E, Shafqat J, Thunnissen MMGM, Haeggström JZ. Leukotriene A4 Hydrolase, Insights into the Molecular Evolution by Homology Modeling and Mutational Analysis of Enzyme from Saccharomyces cerevisiae. J Biol Chem 2005; 280:33477-86. [PMID: 16024909 DOI: 10.1074/jbc.m506821200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian leukotriene A4 (LTA4) hydrolase is a bifunctional zinc metalloenzyme possessing an Arg/Ala aminopeptidase and an epoxide hydrolase activity, which converts LTA4 into the chemoattractant LTB4. We have previously cloned an LTA4 hydrolase from Saccharomyces cerevisiae with a primitive epoxide hydrolase activity and a Leu aminopeptidase activity, which is stimulated by LTA4. Here we used a modeled structure of S. cerevisiae LTA4 hydrolase, mutational analysis, and binding studies to show that Glu-316 and Arg-627 are critical for catalysis, allowing us to a propose a mechanism for the epoxide hydrolase activity. Guided by the structure, we engineered S. cerevisiae LTA4 hydrolase to attain catalytic properties resembling those of human LTA4 hydrolase. Thus, six consecutive point mutations gradually introduced a novel Arg aminopeptidase activity and caused the specific Ala and Pro aminopeptidase activities to increase 24 and 63 times, respectively. In contrast to the wild type enzyme, the hexuple mutant was inhibited by LTA4 for all tested substrates and to the same extent as for the human enzyme. In addition, these mutations improved binding of LTA4 and increased the relative formation of LTB4, whereas the turnover of this substrate was only weakly affected. Our results suggest that during evolution, the active site of an ancestral eukaryotic zinc aminopeptidase has been reshaped to accommodate lipid substrates while using already existing catalytic residues for a novel, gradually evolving, epoxide hydrolase activity. Moreover, the unique ability to catalyze LTB4 synthesis appears to be the result of multiple and subtle structural rearrangements at the catalytic center rather than a limited set of specific amino acid substitutions.
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Affiliation(s)
- Fredrik Tholander
- Department of Medical Biochemistry and Biophysics, Divisions of Chemistry 1 and 2, Karolinska Institutet, Stockholm S-171 77, Sweden
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8
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Morgan EL, Maskrey BH, Rowley AF. At what stage in metazoan evolution did leukotriene generation first appear?--key insights from cartilaginous fish. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2005; 29:53-59. [PMID: 15325523 DOI: 10.1016/j.dci.2004.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2004] [Revised: 04/19/2004] [Accepted: 05/06/2004] [Indexed: 05/24/2023]
Abstract
Leukotriene (LT) B4 is a key player in inflammatory responses in mammals. During the generation of this derivative of arachidonic acid, the unstable product of 5-lipoxygenase, termed LTA4, is converted to LTB4 by LTA4 hydrolase. Invertebrates do not generate LTs yet all vertebrates from bony fish onwards synthesize this compound. As cartilaginous fish are the most primitive living jawed vertebrates, we investigated if the leukocytes from such a fish, the Thornback ray (Raja clavata) could generate LTB4. Supernatants from ionophore-challenged leukocytes generated the 5-lipoxygenase products, 6-trans-LTB4 and 6-trans-12-epi-LTB4 but were unable to synthesize LTB4. To determine if these cells contained an active LTA4 hydrolase, LTA4 was incubated with lysates from ray leukocytes. Such preparations did not contain any demonstrable LTA4 hydrolase activity. Our findings imply at the stage of cartilaginous fish evolution over 350 million years ago that the evolution of an active LTA4 hydrolase had yet to occur.
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Affiliation(s)
- Elizabeth L Morgan
- School of Biological Sciences, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, Wales, UK
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Haeggström JZ. Leukotriene A4 hydrolase/aminopeptidase, the gatekeeper of chemotactic leukotriene B4 biosynthesis. J Biol Chem 2004; 279:50639-42. [PMID: 15339917 DOI: 10.1074/jbc.r400027200] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Jesper Z Haeggström
- Department of Medical Biochemistry and Biophysics, Division of Chemistry 2, Karolinska Institutet, S-171 77 Stockholm, Sweden.
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10
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Kovaleva ES, Masler EP, Skantar AM, Chitwood DJ. Novel matrix metalloproteinase from the cyst nematodes Heterodera glycines and Globodera rostochiensis. Mol Biochem Parasitol 2004; 136:109-12. [PMID: 15138072 DOI: 10.1016/j.molbiopara.2004.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2003] [Revised: 03/05/2004] [Accepted: 03/08/2004] [Indexed: 10/26/2022]
Affiliation(s)
- Elena S Kovaleva
- Nematology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA
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11
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Rudberg PC, Tholander F, Andberg M, Thunnissen MMGM, Haeggström JZ. Leukotriene A4 Hydrolase. J Biol Chem 2004; 279:27376-82. [PMID: 15078870 DOI: 10.1074/jbc.m401031200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leukotriene (LT) A(4) hydrolase is a bifunctional zinc metalloenzyme, which converts LTA(4) into the neutrophil chemoattractant LTB(4) and also exhibits an anion-dependent aminopeptidase activity. In the x-ray crystal structure of LTA(4) hydrolase, Arg(563) and Lys(565) are found at the entrance of the active center. Here we report that replacement of Arg(563), but not Lys(565), leads to complete abrogation of the epoxide hydrolase activity. However, mutations of Arg(563) do not seem to affect substrate binding strength, because values of K(i) for LTA(4) are almost identical for wild type and (R563K)LTA(4) hydrolase. These results are supported by the 2.3-A crystal structure of (R563A)LTA(4) hydrolase, which does not reveal structural changes that can explain the complete loss of enzyme function. For the aminopeptidase reaction, mutations of Arg(563) reduce the catalytic activity (V(max) = 0.3-20%), whereas mutations of Lys(565) have limited effect on catalysis (V(max) = 58-108%). However, in (K565A)- and (K565M)LTA(4) hydrolase, i.e. mutants lacking a positive charge, values of the Michaelis constant for alanine-p-nitroanilide increase significantly (K(m) = 480-640%). Together, our data indicate that Arg(563) plays an unexpected, critical role in the epoxide hydrolase reaction, presumably in the positioning of the carboxylate tail to ensure perfect substrate alignment along the catalytic elements of the active site. In the aminopeptidase reaction, Arg(563) and Lys(565) seem to cooperate to provide sufficient binding strength and productive alignment of the substrate. In conclusion, Arg(563) and Lys(565) possess distinct roles as carboxylate recognition sites for two chemically different substrates, each of which is turned over in separate enzymatic reactions catalyzed by LTA(4) hydrolase.
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Affiliation(s)
- Peter C Rudberg
- Department of Medical Biochemistry and Biophysics, Division of Chemistry II, Karolinska Institutet, S-171 77 Stockholm, Sweden
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12
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Brooks DR, Hooper NM, Isaac RE. The Caenorhabditis elegans orthologue of mammalian puromycin-sensitive aminopeptidase has roles in embryogenesis and reproduction. J Biol Chem 2003; 278:42795-801. [PMID: 12930831 DOI: 10.1074/jbc.m306216200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammals possess membrane-associated and cytosolic forms of the puromycin-sensitive aminopeptidase (PSA; EC 3.4.11.14). Increasing evidence suggests the membrane PSA is involved in neuromodulation within the central nervous system and in reproductive biology. The functional roles of the cytosolic PSA are less clear. The genome of the nematode Caenorhabditis elegans encodes an aminopeptidase, F49E8.3 (PAM-1), that is orthologous to PSA, and sequence analysis predicts it to be cytosolic. We have determined the spatio/temporal gene expression pattern of pam-1 by using the promoter region of F49E8.3 to control expression in the nematode of a second exon translational fusion of the aminopeptidase to green fluorescent protein. Cytosolic fluorescence was observed throughout development in the intestine and nerve cells of the head. Neuronal expression was also observed in the tail of adult males. Recombinant PAM-1, expressed and purified from Escherichia coli, hydrolyzed the N-terminal amino acid from peptide substrates. Favored substrates had positively charged or small neutral amino acids in the N-terminal position. Peptide hydrolysis was inhibited by the metal-chelating agent 1,10-phenanthroline and by the aminopeptidase inhibitors actinonin, amastatin, and leuhistin. However, the enzyme was approximately 100-fold less sensitive toward puromycin (IC50, 135 mum) than other PSA homologues. Following inactivation of the enzyme, aminopeptidase activity was recovered with Zn2+, Co2+, and Ni2+. Silencing expression of pam-1 by RNA interference resulted in 30% embryonic lethality. Surviving adult hermaphrodites deposited large numbers of oocytes throughout the self-fertile period. The overall brood size was, however, unaffected. We conclude that pam-1 encodes an aminopeptidase that clusters phylogenetically with the PSAs, despite attenuated sensitivity toward puromycin, and that it functions in embryo development and reproduction of the nematode.
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Affiliation(s)
- Darren R Brooks
- Molecular and Cellular Biosciences, Faculty of Biological Sciences, University of Leeds, Miall Bldg., Leeds, West Yorkshire LS2 9JT, United Kingdom.
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13
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Masler EP. In vitro metabolism of an insect neuropeptide by homogenates of the nematode Caenorhabditis elegans. J Helminthol 2003; 77:43-8. [PMID: 12590664 DOI: 10.1079/joh2002152] [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: 11/11/2022]
Abstract
The cytosolic fraction of homogenates from the free-living soil nematode Caenorhabditis elegans is capable of metabolizing the insect neuropeptide adipokinetic hormone, a decapeptide blocked at the N-terminus by a pGlu residue. Analysis of digests by RP-HPLC and LC-MS revealed that an initial endoproteolytic cleavage step produced a heptapeptide with an unblocked N-terminus that can serve as a substrate for aminopeptidases. The aminopeptidase activity is depressed in the presence of the inhibitor amastatin; the initial product of the endoproteolytic step accumulates during incubation, and expected aminopeptidase product peptides are reduced in amount, as assessed by chromatographic peak size. The absence of some expected peptide fragments in the reaction mixtures suggests that multiple proteases contribute to short peptide half-lives. Comparison of the adipokinetic hormone digestion in C. elegans to that reported previously for insects reveals the same general pattern of peptide fragment production.
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Affiliation(s)
- E P Masler
- Nematology Laboratory, United States Department of Agriculture, Agricultural Research Service, 10300 Baltimore Blvd, R-165B, B-011A, BARC-West, Beltsville, MD 20705, USA.
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Haeggström JZ, Kull F, Rudberg PC, Tholander F, Thunnissen MMGM. Leukotriene A4 hydrolase. Prostaglandins Other Lipid Mediat 2002; 68-69:495-510. [PMID: 12432939 DOI: 10.1016/s0090-6980(02)00051-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The leukotrienes (LTs) are a family of lipid mediators involved in inflammation and allergy. Leukotriene B4 is a classical chemoattractant, which triggers adherence and aggregation of leukocytes to the endothelium at only nanomolar concentrations. In addition, leukotriene B4 modulates immune responses, participates in the host-defense against infections, and is a key mediator of PAF-induced lethal shock. Because of these powerful biological effects, leukotriene B4 is implicated in a variety of acute and chronic inflammatory diseases, e.g. nephritis, arthritis, dermatitis, and chronic obstructive pulmonary disease. The final step in the biosynthesis of leukotriene B4 is catalyzed by leukotriene A4 hydrolase, a unique bi-functional zinc metalloenzyme with an anion-dependent aminopeptidase activity. Here we describe the most recent developments regarding our understanding of the structure, function, and catalytic mechanisms of leukotriene A4 hydrolase.
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Affiliation(s)
- Jesper Z Haeggström
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
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15
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Masler EP. Aminopeptidases in Caenorhabditis elegans and Panagrellus redivivus: detection using peptide and non-peptide substrates. J Helminthol 2002; 76:45-52. [PMID: 12018195 DOI: 10.1079/joh200193] [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: 11/11/2022]
Abstract
Aminopeptidase activities were detected in extracts of the free-living nematodes Caenorhabditis elegans and Panagrellus redivivus using the aminoacyl substrate L-alanine-4-nitroanilide. The activities exhibited similarities in Km (C. elegans = 2.22 mM; P. redivivus = 2.09 mM) and specific activity (C. elegans = 1.38 +/- 0.43 mAU min(-1) x g(-1); P. redivivus, 1.23 +/- 0.18m AU min(-1) microg(-1). Each is inhibited competitively by amastatin (C. elegans IC50 = 0.46 microM; P. redivivus IC50 = 15.90 microM) and non-competitively by leuhistin (C. elegans IC50 = 3.00 microM; P. redivivus IC50 = 37.35 microM). The bioactive peptides adipokinetic hormone and substance P decrease the apparent aminopeptidase activities of each extract suggesting that the peptides compete with the Ala-pNA as substrates. With each extract, adipokinetic hormone appeared to be the more effective substrate. Digestion of adipokinetic hormone by C. elegans and P. redivivus extracts in the presence and absence of 1 mM amastatin produced distinct chromatographic profiles that suggest different digestion patterns for the two species. However, amastatin had clear effects on chromatographic profiles from each species indicating that an aminopeptidase is involved in the digestion of the peptide substrates. The data presented indicate that extracts of free-living nematodes are capable of metabolizing peptide hormones, and that this metabolism involves substrate-selective aminopeptidases.
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Affiliation(s)
- E P Masler
- Nematology Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705-2350, USA.
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Kull F, Ohlson E, Lind B, Haeggström JZ. Saccharomyces cerevisiae leukotriene A4 hydrolase: formation of leukotriene B4 and identification of catalytic residues. Biochemistry 2001; 40:12695-703. [PMID: 11601994 DOI: 10.1021/bi011348p] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Leukotriene A(4) hydrolase in mammals is a bifunctional zinc metalloenzyme that catalyzes the hydrolysis of leukotriene A(4) into the proinflammatory mediator leukotriene B(4), and also possesses an aminopeptidase activity. Recently we cloned and characterized an leukotriene A(4) hydrolase from Saccharomyces cerevisiae as a leucyl aminopeptidase with an epoxide hydrolase activity. Here we show that S. cerevisiae leukotriene A(4) hydrolase is a metalloenzyme containing one zinc atom complexed to His-340, His-344, and Glu-363. Mutagenetic analysis indicates that the aminopeptidase activity follows a general base mechanism with Glu-341 and Tyr-429 as the base and proton donor, respectively. Furthermore, the yeast enzyme hydrolyzes leukotriene A(4) into three compounds, viz., 5S,6S-dihydroxy-7,9-trans-11,14-cis-eicosatetraenoic acid, leukotriene B(4), and Delta(6)-trans-Delta(8)-cis-leukotriene B(4), with a relative formation of 1:0.2:0.1. In addition, exposure of S. cerevisiae leukotriene A(4) hydrolase to leukotriene A(4) selectively inactivates the epoxide hydrolase activity with a simultaneous stimulation of the aminopeptidase activity. Moreover, kinetic analyses of wild-type and mutated S. cerevisiae leukotriene A(4) hydrolase suggest that leukotriene A(4) binds in one catalytic mode and one tight-binding, regulatory mode. Exchange of a Phe-424 in S. cerevisiae leukotriene A(4) hydrolase for a Tyr, the corresponding residue in human leukotriene A(4) hydrolase, results in a protein that converts leukotriene A(4) into leukotriene B(4) with an improved efficiency and specificity. Hence, by a single point mutation, we could make the active site better suited to bind and turn over the substrate leukotriene A(4), thus mimicking a distinct step in the molecular evolution of S. cerevisiae leukotriene A(4) hydrolase toward its mammalian counterparts.
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Affiliation(s)
- F Kull
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden
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Affiliation(s)
- J Z Haeggström
- Department of Medical Biochemistry and Biophysics, Division of Chemistry II, Karolinska Institutet, Stockholm, Sweden.
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Kull F, Ohlson E, Haeggström JZ. Cloning and characterization of a bifunctional leukotriene A(4) hydrolase from Saccharomyces cerevisiae. J Biol Chem 1999; 274:34683-90. [PMID: 10574934 DOI: 10.1074/jbc.274.49.34683] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In mammals, leukotriene A(4) hydrolase is a bifunctional zinc metalloenzyme that catalyzes hydrolysis of leukotriene A(4) into the proinflammatory leukotriene B(4) and also possesses an arginyl aminopeptidase activity. We have cloned, expressed, and characterized a protein from Saccharomyces cerevisiae that is 42% identical to human leukotriene A(4) hydrolase. The purified protein is an anion-activated leucyl aminopeptidase, as assessed by p-nitroanilide substrates, and does not hydrolyze leukotriene A(4) into detectable amounts of leukotriene B(4). However, the S. cerevisiae enzyme can utilize leukotriene A(4) as substrate to produce a compound identified as 5S,6S-dihydroxy-7,9-trans-11, 14-cis-eicosatetraenoic acid. Both catalytic activities are inhibited by 3-(4-benzyloxyphenyl)-2-(R)-amino-1-propanethiol (thioamine), a competitive inhibitor of human leukotriene A(4) hydrolase. Furthermore, the peptide cleaving activity of the S. cerevisiae enzyme was stimulated approximately 10-fold by leukotriene A(4) with kinetics indicating the presence of a lipid binding site. Nonenzymatic hydrolysis products of leukotriene A(4), leukotriene B(4), arachidonic acid, or phosphatidylcholine were without effect. Moreover, leukotriene A(4) could displace the inhibitor thioamine and restore maximal aminopeptidase activity, indicating that the leukotriene A(4) binding site is located at the active center of the enzyme. Hence, the S. cerevisiae leukotriene A(4) hydrolase is a bifunctional enzyme and appears to be an early ancestor to mammalian leukotriene A(4) hydrolases.
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Affiliation(s)
- F Kull
- Department of Medical Biochemistry, Division of Chemistry II, Karolinska Institutet, S-171 77 Stockholm, Sweden
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