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Zhang H, Fu Y, Wang L, Liang A, Chen S, Xu A. Identifying novel conopepetides from the venom ducts of Conus litteratus through integrating transcriptomics and proteomics. J Proteomics 2018; 192:346-357. [PMID: 30267875 DOI: 10.1016/j.jprot.2018.09.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/20/2018] [Accepted: 09/25/2018] [Indexed: 12/17/2022]
Abstract
The venom ducts of marine cone snails secrete highly complex mixtures of cysteine-rich active peptides, which are generally known as conotoxins or conopeptides and provide a potential fertile resource for pharmacological neuroscience research and the discovery of new drugs. Previous studies have devoted substantial effort to the identification of novel conopeptides, and the 109 cone snail species have yielded 7000 known conopeptides to date. Here, we used de novo deep transcriptome sequencing analyses combined with traditional Sanger sequencing and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) to identify 30 distinct conopeptide precursors. Twenty of these were previously reported and the other 10 were novel conopeptide precursors. The study provides the first identification of the Con-ikot-ikot, NSF-bt05, O3 and I1 gene superfamilies in C. litteratus. A new putative superfamily was identified. In addition, the following cysteine frameworks were first identified in this study: CC-C-C-C-C-C-C-C-C-C-C-C-CC-C-C-C-C-C and C-C-C-C-C-CC-C. Several isomerases involved in post-translational modification of conopeptides were identified as well. The discovery of new conopeptides in C. litteratus will enhance our understanding of the conopeptide diversity in this particular clade of cone snails. We also found the existence of intraspecific variations in vermivorous species. Finally, the analysis strategy offers a relatively reliable workflow for screening for peptide drug candidates. SIGNIFICANCE: These novel conopeptides provide a potential resource for the development of new channel-targeting drugs. The intraspecific variation in C. litteratus enhance our understanding of the conopeptide diversity in this particular clade of cone snails. The identified three cysteine residues, which might participate in the formation of disulfide bonds, provide a clue to get the connectivity of cysteine frameworks. Finally, the analysis strategy offers a relatively reliable workflow for screening for peptide drug candidates.
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Affiliation(s)
- Han Zhang
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China; Shenzhen Research Institute, Sun Yat-Sen University, People's Republic of China
| | - Yonggui Fu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China; Shenzhen Research Institute, Sun Yat-Sen University, People's Republic of China
| | - Lei Wang
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China; Shenzhen Research Institute, Sun Yat-Sen University, People's Republic of China
| | - Anwen Liang
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Shangwu Chen
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China; Shenzhen Research Institute, Sun Yat-Sen University, People's Republic of China.
| | - Anlong Xu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China; School of Life Science, Beijing University of Chinese Medicine, Beijing 100029, People's Republic of China.
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Zhu X, Bi J, Yu J, Li X, Zhang Y, Zhangsun D, Luo S. Recombinant Expression and Characterization of α-Conotoxin LvIA in Escherichia coli. Mar Drugs 2016; 14:11. [PMID: 26742048 PMCID: PMC4728508 DOI: 10.3390/md14010011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/11/2015] [Accepted: 12/28/2015] [Indexed: 01/17/2023] Open
Abstract
α-Conotoxin LvIA is derived from Conus lividus, native to Hainan, and is the most selective inhibitor of α3β2 nicotinic acetylcholine receptors (nAChRs) known to date. In this study, an efficient approach for the production of recombinant α-Conotoxin LvIA is described. Tandem repeats of a LvIA gene fragment were constructed and fused with a KSI gene and a His6 tag in a Escherichia coli (E. coli) expression vector pET-31b(+). The recombinant plasmids were transformed into E. coli and were found to express well. The KSI-(LvIA)n-His6 fusion protein was purified by metal affinity chromatography and then cleaved with CNBr to release recombinant LvIA (rLvIA). High yields of fusion protein ranging from 100 to 500 mg/L culture were obtained. The pharmacological profile of rLvIA was determined by two-electrode voltage-clamp electrophysiology in Xenopus laevis oocytes expressing rat nAChR subtypes. The rLvIA antagonized the α3β2 nAChR subtype selectively with a nano-molar IC50. The rLvIA was analgesic in a mouse hot-plate test model of pain. Overall, this study provides an effective method to synthesize α-conotoxin LvIA in an E. coli recombinant expression system, and this approach could be useful to obtain active conopeptides in large quantity and at low cost.
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Affiliation(s)
- Xiaopeng Zhu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
- College of Horticulture and Landscapes, Hainan University, Haikou 570228, China.
- College of Marine Science, Hainan University, Haikou 570228, China.
| | - Jianpeng Bi
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Jinpeng Yu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Xiaodan Li
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Yaning Zhang
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
- College of Marine Science, Hainan University, Haikou 570228, China.
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
- College of Marine Science, Hainan University, Haikou 570228, China.
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Safavi-Hemami H, Siero WA, Kuang Z, Williamson NA, Karas JA, Page LR, MacMillan D, Callaghan B, Kompella SN, Adams DJ, Norton RS, Purcell AW. Embryonic toxin expression in the cone snail Conus victoriae: primed to kill or divergent function? J Biol Chem 2011; 286:22546-57. [PMID: 21504902 DOI: 10.1074/jbc.m110.217703] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Predatory marine cone snails (genus Conus) utilize complex venoms mainly composed of small peptide toxins that target voltage- and ligand-gated ion channels in their prey. Although the venoms of a number of cone snail species have been intensively profiled and functionally characterized, nothing is known about the initiation of venom expression at an early developmental stage. Here, we report on the expression of venom mRNA in embryos of Conus victoriae and the identification of novel α- and O-conotoxin sequences. Embryonic toxin mRNA expression is initiated well before differentiation of the venom gland, the organ of venom biosynthesis. Structural and functional studies revealed that the embryonic α-conotoxins exhibit the same basic three-dimensional structure as the most abundant adult toxin but significantly differ in their neurological targets. Based on these findings, we postulate that the venom repertoire of cone snails undergoes ontogenetic changes most likely reflecting differences in the biotic interactions of these animals with their prey, predators, or competitors. To our knowledge, this is the first study to show toxin mRNA transcripts in embryos, a finding that extends our understanding of the early onset of venom expression in animals and may suggest alternative functions of peptide toxins during development.
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Affiliation(s)
- Helena Safavi-Hemami
- Department of Biochemistry and Molecular Biology, University of Melbourne, 3010 Victoria, Australia
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Luo S, Akondi KB, Zhangsun D, Wu Y, Zhu X, Hu Y, Christensen S, Dowell C, Daly NL, Craik DJ, Wang CIA, Lewis RJ, Alewood PF, Michael McIntosh J. Atypical alpha-conotoxin LtIA from Conus litteratus targets a novel microsite of the alpha3beta2 nicotinic receptor. J Biol Chem 2010; 285:12355-66. [PMID: 20145249 DOI: 10.1074/jbc.m109.079012] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Different nicotinic acetylcholine receptor (nAChR) subtypes are implicated in learning, pain sensation, and disease states, including Parkinson disease and nicotine addiction. alpha-Conotoxins are among the most selective nAChR ligands. Mechanistic insights into the structure, function, and receptor interaction of alpha-conotoxins may serve as a platform for development of new therapies. Previously characterized alpha-conotoxins have a highly conserved Ser-Xaa-Pro motif that is crucial for potent nAChR interaction. This study characterized the novel alpha-conotoxin LtIA, which lacks this highly conserved motif but potently blocked alpha3beta2 nAChRs with a 9.8 nm IC(50) value. The off-rate of LtIA was rapid relative to Ser-Xaa-Pro-containing alpha-conotoxin MII. Nevertheless, pre-block of alpha3beta2 nAChRs with LtIA prevented the slowly reversible block associated with MII, suggesting overlap in their binding sites. nAChR beta subunit ligand-binding interface mutations were used to examine the >1000-fold selectivity difference of LtIA for alpha3beta2 versus alpha3beta4 nAChRs. Unlike MII, LtIA had a >900-fold increased IC(50) value on alpha3beta2(F119Q) versus wild type nAChRs, whereas T59K and V111I beta2 mutants had little effect. Molecular docking simulations suggested that LtIA had a surprisingly shallow binding site on the alpha3beta2 nAChR that includes beta2 Lys-79. The K79A mutant disrupted LtIA binding but was without effect on an LtIA analog where the Ser-Xaa-Pro motif is present, consistent with distinct binding modes.
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Affiliation(s)
- Sulan Luo
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Ocean College, College of Materials and Chemical Engineering, Center for Experimental Biotechnology, Hainan University, Haikou Hainan 570228, China.
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Alpha-conotoxins as pharmacological probes of nicotinic acetylcholine receptors. Acta Pharmacol Sin 2009; 30:771-83. [PMID: 19448650 DOI: 10.1038/aps.2009.47] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Cysteine-rich peptides from the venom of cone snails (Conus) target a wide variety of different ion channels. One family of conopeptides, the alpha-conotoxins, specifically target different isoforms of nicotinic acetylcholine receptors (nAChRs) found both in the neuromuscular junction and central nervous system. This family is further divided into subfamilies based on the number of amino acids between cysteine residues. The exquisite subtype selectivity of certain alpha-conotoxins has been key to the characterization of native nAChR isoforms involved in modulation of neurotransmitter release, the pathophysiology of Parkinson's disease and nociception. Structure/function characterization of alpha-conotoxins has led to the development of analogs with improved potency and/or subtype selectivity. Cyclization of the backbone structure and addition of lipophilic moieties has led to improved stability and bioavailability of alpha-conotoxins, thus paving the way for orally available therapeutics. The recent advances in phylogeny, exogenomics and molecular modeling promises the discovery of an even greater number of alpha-conotoxins and analogs with improved selectivity for specific subtypes of nAChRs.
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Loughnan ML, Nicke A, Lawrence N, Lewis RJ. Novel αD-Conopeptides and Their Precursors Identified by cDNA Cloning Define the D-Conotoxin Superfamily. Biochemistry 2009; 48:3717-29. [DOI: 10.1021/bi9000326] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Marion L. Loughnan
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia, and Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt/Main, Germany
| | - Annette Nicke
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia, and Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt/Main, Germany
| | - Nicole Lawrence
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia, and Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt/Main, Germany
| | - Richard J. Lewis
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia, and Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt/Main, Germany
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