1
|
Bagheri-Ziari S, Shahbazzadeh D, Sardari S, Sabatier JM, Pooshang Bagheri K. Discovery of a New Analgesic Peptide, Leptucin, from the Iranian Scorpion, Hemiscorpius lepturus. Molecules 2021; 26:molecules26092580. [PMID: 33925223 PMCID: PMC8124257 DOI: 10.3390/molecules26092580] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/25/2021] [Accepted: 04/26/2021] [Indexed: 01/07/2023] Open
Abstract
Hemiscorpius lepturus scorpion stings do not induce considerable pain based on epidemiological surveys conducted in the southwest part of Iran. Accordingly, this study was aimed to identify the analgesic molecule in H. lepturus venom by analyzing a cDNA library of the scorpion venom gland looking for sequences having homology with known animal venom analgesic peptides. The analgesic molecule is a cysteine rich peptide of 55 amino acids. the synthetic peptide was deprotected and refolded. RP-HPLC, Ellman's, and DLS assays confirmed the refolding accuracy. Circular dichroism (CD) showed helix and beta sheet contents. This peptide, called leptucin, demonstrated 95% analgesic activity at the dose of 0.48 mg/kg in hot plate assay. Leptucin at the doses of 0.32, 0.48, and 0.64 mg/kg showed 100% activity in thermal tail flick test. No hemolysis or cytotoxicity was observed at 8 and 16 µg. Histopathology evaluations indicated no hepatotoxicity, nephrotoxicity, and cardiotoxicity. We thus report that leptucin is the analgesic agent of H. lepturus venom. Regarding the high in vivo efficacy of leptucin and the fact it shows no observable toxicity, it could be suggested as a drug lead in a preclinical study of acute pain as well as the study of its mechanism of action.
Collapse
Affiliation(s)
- Sedigheh Bagheri-Ziari
- Venom and Biotherapeutics Molecules Laboratory, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran 1316943551, Iran; (S.B.-Z.); (D.S.)
| | - Delavar Shahbazzadeh
- Venom and Biotherapeutics Molecules Laboratory, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran 1316943551, Iran; (S.B.-Z.); (D.S.)
| | - Soroush Sardari
- Drug Design and Bioinformatics Unit, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran 1316943551, Iran;
| | - Jean-Marc Sabatier
- Institute of NeuroPhysiopathology (INP), Faculté de Pharmacie, Université d’Aix-Marseille, UMR 7051, 27 Bd Jean Moulin, CEDEX, 13385 Marseille, France;
| | - Kamran Pooshang Bagheri
- Venom and Biotherapeutics Molecules Laboratory, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran 1316943551, Iran; (S.B.-Z.); (D.S.)
- Correspondence:
| |
Collapse
|
2
|
Munasinghe NR, Christie MJ. Conotoxins That Could Provide Analgesia through Voltage Gated Sodium Channel Inhibition. Toxins (Basel) 2015; 7:5386-407. [PMID: 26690478 PMCID: PMC4690140 DOI: 10.3390/toxins7124890] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/23/2015] [Accepted: 11/19/2015] [Indexed: 12/19/2022] Open
Abstract
Chronic pain creates a large socio-economic burden around the world. It is physically and mentally debilitating, and many sufferers are unresponsive to current therapeutics. Many drugs that provide pain relief have adverse side effects and addiction liabilities. Therefore, a great need has risen for alternative treatment strategies. One rich source of potential analgesic compounds that has emerged over the past few decades are conotoxins. These toxins are extremely diverse and display selective activity at ion channels. Voltage gated sodium (NaV) channels are one such group of ion channels that play a significant role in multiple pain pathways. This review will explore the literature around conotoxins that bind NaV channels and determine their analgesic potential.
Collapse
Affiliation(s)
- Nehan R Munasinghe
- Discipline of Pharmacology, The University of Sydney, Sydney, NSW 2006, Australia.
| | - MacDonald J Christie
- Discipline of Pharmacology, The University of Sydney, Sydney, NSW 2006, Australia.
| |
Collapse
|
3
|
Akondi KB, Muttenthaler M, Dutertre S, Kaas Q, Craik DJ, Lewis RJ, Alewood PF. Discovery, synthesis, and structure-activity relationships of conotoxins. Chem Rev 2014; 114:5815-47. [PMID: 24720541 PMCID: PMC7610532 DOI: 10.1021/cr400401e] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | | | - Sébastien Dutertre
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| |
Collapse
|
4
|
Molecular evolution and diversity of Conus peptide toxins, as revealed by gene structure and intron sequence analyses. PLoS One 2013; 8:e82495. [PMID: 24349297 PMCID: PMC3862624 DOI: 10.1371/journal.pone.0082495] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 10/25/2013] [Indexed: 11/19/2022] Open
Abstract
Cone snails, which are predatory marine gastropods, produce a cocktail of venoms used for predation, defense and competition. The major venom component, conotoxin, has received significant attention because it is useful in neuroscience research, drug development and molecular diversity studies. In this study, we report the genomic characterization of nine conotoxin gene superfamilies from 18 Conus species and investigate the relationships among conotoxin gene structure, molecular evolution and diversity. The I1, I2, M, O2, O3, P, S, and T superfamily precursors all contain three exons and two introns, while A superfamily members contain two exons and one intron. The introns are conserved within a certain gene superfamily, and also conserved across different Conus species, but divergent among different superfamilies. The intronic sequences contain many simple repeat sequences and regulatory elements that may influence conotoxin gene expression. Furthermore, due to the unique gene structure of conotoxins, the base substitution rates and the number of positively selected sites vary greatly among exons. Many more point mutations and trinucleotide indels were observed in the mature peptide exon than in the other exons. In addition, the first example of alternative splicing in conotoxin genes was found. These results suggest that the diversity of conotoxin genes has been shaped by point mutations and indels, as well as rare gene recombination or alternative splicing events, and that the unique gene structures could have made a contribution to the evolution of conotoxin genes.
Collapse
|
5
|
Gyanda R, Banerjee J, Chang YP, Phillips AM, Toll L, Armishaw CJ. Oxidative folding and preparation of α-conotoxins for use in high-throughput structure-activity relationship studies. J Pept Sci 2012. [PMID: 23193084 DOI: 10.1002/psc.2467] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
α-Conotoxins are peptide neurotoxins that selectively inhibit various subtypes of nicotinic acetylcholine receptors. They are important research tools for studying numerous pharmacological disorders, with profound potential for developing drug leads for treating pain, tobacco addiction, and other conditions. They are characterized by the presence of two disulfide bonds connected in a globular arrangement, which stabilizes a bioactive helical conformation. Despite extensive structure-activity relationship studies that have produced α-conotoxin analogs with increased potency and selectivity towards specific nicotinic acetylcholine receptor subtypes, the efficient production of diversity-oriented α-conotoxin combinatorial libraries has been limited by inefficient folding and purification procedures. We have investigated the optimized conditions for the reliable folding of α-conotoxins using simplified oxidation procedures for use in the accelerated production of synthetic combinatorial libraries of α-conotoxins. To this end, the effect of co-solvent, redox reagents, pH, and temperature on the proportion of disulfide bond isomers was determined for α-conotoxins exhibiting commonly known Cys loop spacing frameworks. In addition, we have developed high-throughput 'semi-purification' methods for the quick and efficient parallel preparation of α-conotoxin libraries for use in accelerated structure-activity relationship studies. Our simplified procedures represent an effective strategy for the preparation of large arrays of correctly folded α-conotoxin analogs and permit the rapid identification of active hits directly from high-throughput pharmacological screening assays.
Collapse
Affiliation(s)
- Reena Gyanda
- Torrey Pines Institute for Molecular Studies, Port St Lucie, Florida 34987, USA
| | | | | | | | | | | |
Collapse
|
6
|
Bingham JP, Andrews EA, Kiyabu SM, Cabalteja CC. Drugs from slugs. Part II--conopeptide bioengineering. Chem Biol Interact 2012; 200:92-113. [PMID: 23063744 DOI: 10.1016/j.cbi.2012.09.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 08/27/2012] [Accepted: 09/17/2012] [Indexed: 11/27/2022]
Abstract
The biological transformation of toxins as research probes, or as pharmaceutical drug leads, is an onerous and drawn out process. Issues regarding changes to pharmacological specificity, desired potency, and bioavailability are compounded naturally by their inherent toxicity. These often scuttle their progress as they move up the narrowing drug development pipeline. Yet one class of peptide toxins, from the genus Conus, has in many ways spearheaded the expansion of new peptide bioengineering techniques to aid peptide toxin pharmaceutical development. What has now emerged is the sequential bioengineering of new research probes and drug leads that owe their lineage to these highly potent and isoform specific peptides. Here we discuss the progressive bioengineering steps that many conopeptides have transitioned through, and specifically illustrate some of the biochemical approaches that have been established to maximize their biological research potential and pharmaceutical worth.
Collapse
Affiliation(s)
- Jon-Paul Bingham
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, HI 96822, USA.
| | | | | | | |
Collapse
|
7
|
Okumura M, Shimamoto S, Hidaka Y. A chemical method for investigating disulfide-coupled peptide and protein folding. FEBS J 2012; 279:2283-95. [PMID: 22487262 DOI: 10.1111/j.1742-4658.2012.08596.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Investigations of protein folding have largely involved studies using disulfide-containing proteins, as disulfide-coupled folding of proteins permits the folding intermediates to be trapped and their conformations determined. Over the last decade, a combination of new biotechnical and chemical methodology has resulted in a remarkable acceleration in our understanding of the mechanism of disulfide-coupled protein folding. In particular, expressed protein ligation, a combination of native chemical ligation and an intein-based approach, permits specifically labeled proteins to be easily produced for studies of protein folding using biophysical methods, such as NMR spectroscopy and X-ray crystallography. A method for regio-selective formation of disulfide bonds using chemical procedures has also been established. This strategy is particularly relevant for the study of disulfide-coupled protein folding, and provides us not only with the native conformation, but also the kinetically trapped topological isomer with native disulfide bonds. Here we review recent developments and applications of biotechnical and chemical methods to investigations of disulfide-coupled peptide and protein folding. Chemical additives designed to accelerate correct protein folding and to avoid non-specific aggregation are also discussed.
Collapse
Affiliation(s)
- Masaki Okumura
- Faculty of Science and Engineering, Kinki University, Higashi-osaka, Osaka, Japan
| | | | | |
Collapse
|
8
|
Ionic liquid applications in peptide chemistry: synthesis, purification and analytical characterization processes. Molecules 2012; 17:4158-85. [PMID: 22481538 PMCID: PMC6268249 DOI: 10.3390/molecules17044158] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 03/22/2012] [Accepted: 03/28/2012] [Indexed: 11/17/2022] Open
Abstract
This review aims to provide a comprehensive overview of the recent advances made in the field of ionic liquids in peptide chemistry and peptide analytics.
Collapse
|
9
|
Steiner AM, Bulaj G. Optimization of oxidative folding methods for cysteine-rich peptides: a study of conotoxins containing three disulfide bridges. J Pept Sci 2011; 17:1-7. [PMID: 20814907 DOI: 10.1002/psc.1283] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The oxidative folding of small, cysteine-rich peptides to selectively achieve the native disulfide bond connectivities is critical for discovery and structure-function studies of many bioactive peptides. As the propensity to acquire the native conformation greatly depends on the peptide sequence, numerous empirical oxidation methods are employed. The context-dependent optimization of these methods has thus far precluded a generalized oxidative folding protocol, in particular for peptides containing more than two disulfides. Herein, we compare the efficacy of optimized solution-phase and polymer-supported oxidation methods using three disulfide-bridged conotoxins, namely µ-SIIIA, µ-KIIIA and ω-GVIA. The use of diselenide bridges as proxies for disulfide bridges is also evaluated. We propose the ClearOx-assisted oxidation of selenopeptides as a fairly generalized oxidative folding protocol.
Collapse
Affiliation(s)
- Andrew M Steiner
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, UT 84108, USA
| | | |
Collapse
|
10
|
Bingham JP, Mitsunaga E, Bergeron ZL. Drugs from slugs--past, present and future perspectives of omega-conotoxin research. Chem Biol Interact 2010; 183:1-18. [PMID: 19800874 DOI: 10.1016/j.cbi.2009.09.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/03/2009] [Accepted: 09/24/2009] [Indexed: 12/18/2022]
Abstract
Peptides from the venom of carnivorous cone shells have provided six decades of intense research, which has led to the discovery and development of novel analgesic peptide therapeutics. Our understanding of this unique natural marine resource is however somewhat limited. Given the past pharmacological record, future investigations into the toxinology of these highly venomous tropical marine snails will undoubtedly yield other highly selective ion channel inhibitors and modulators. With over a thousand conotoxin-derived sequences identified to date, those identified as ion channel inhibitors represent only a small fraction of the total. Here we discuss our present understanding of conotoxins, focusing on the omega-conotoxin peptide family, and illustrate how such a seemingly simple snail has yielded a highly effective clinical drug.
Collapse
Affiliation(s)
- Jon-Paul Bingham
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, HI 96822, USA.
| | | | | |
Collapse
|
11
|
Jensen JE, Durek T, Alewood PF, Adams DJ, King GF, Rash LD. Chemical synthesis and folding of APETx2, a potent and selective inhibitor of acid sensing ion channel 3. Toxicon 2009; 54:56-61. [DOI: 10.1016/j.toxicon.2009.03.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 03/06/2009] [Accepted: 03/12/2009] [Indexed: 10/21/2022]
|
12
|
Miloslavina AA, Leipold E, Kijas M, Stark A, Heinemann SH, Imhof D. A room temperature ionic liquid as convenient solvent for the oxidative folding of conopeptides. J Pept Sci 2008; 15:72-7. [DOI: 10.1002/psc.1106] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
13
|
Bulaj G, Olivera BM. Folding of conotoxins: formation of the native disulfide bridges during chemical synthesis and biosynthesis of Conus peptides. Antioxid Redox Signal 2008; 10:141-55. [PMID: 17961068 DOI: 10.1089/ars.2007.1856] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Conopeptides from >700 species of predatory marine Conus snails provide an impressive molecular diversity of cysteine-rich peptides. Most of the estimated 50,000-100,000 distinct conopeptides range in size from 10 to 50 amino acid residues, often with multiple posttranslational modifications. The great majority contain from two to four disulfide bridges. As the biosynthetic and chemical production of this impressive repertoire of disulfide-rich peptides has been investigated, particularly the formation of native disulfide bridges, differences between in vivo and in vitro oxidative folding have become increasingly evident. In this article, we provide an overview of the molecular diversity of conotoxins with an emphasis on the cysteine patterns and disulfide frameworks. The conotoxin folding studies reviewed include regioselective and direct oxidation strategies, recombinant expression, optimization of folding methods, mechanisms of in vitro folding, and preliminary data on the biosynthesis of conotoxins in venom ducts. Despite these studies, how the cone snails efficiently produce properly folded conotoxins remains unanswered. As chemists continue to master oxidative folding techniques, insights gleaned from how conotoxins are folded in vivo will likely lead to the development of the new folding methods, as well as shed some light on fundamental mechanisms relevant to the protein folding problem.
Collapse
Affiliation(s)
- Grzegorz Bulaj
- Department of Medicinal Chemistry, College of Pharmacy, Salt Lake City, Utah 84108, USA.
| | | |
Collapse
|
14
|
Conduit R, Sasse A, Hodgson W, Trinder J, Veasey S, Tucker A. A neurotoxinological approach to the treatment of obstructive sleep apnoea. Sleep Med Rev 2007; 11:361-75. [PMID: 17646118 DOI: 10.1016/j.smrv.2007.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Current treatment approaches to the problem of obstructive sleep apnoea (OSA) have limitations. Specifically, invasive anatomical-based surgery and dental appliances typically do not alleviate obstruction at an acceptable rate, and compliance to continuous positive airway pressure (CPAP) devices is frequently suboptimal. Neurotoxinological treatment approaches are widespread in the field of medicine, but as yet have not been evaluated as a treatment for sleep-disordered breathing. In this review, it is argued that despite widespread recognition of the loss of upper airway (UA) muscular tone and/or reflexes in the expression of OSA, most treatment interventions to date have focused on anatomical principles alone. Several hypothesised neurotoxinological interventions aimed at either enhancing UA neuromuscular tone and/or reflexes are proposed, and some preliminary data is presented. Although in its early infancy, with considerable toxicity studies in animals yet to be done, a neurotoxinological approach to the problem of OSA holds promise as a future treatment, with the potential for both high effectiveness and patient compliance.
Collapse
Affiliation(s)
- Russell Conduit
- School of Psychology, Psychiatry & Psychological Medicine, Faculty of Medicine, Nursing & Health Sciences, Monash University, 900 Dandenong Road Caulfield, Melbourne, Vic 3145, Australia.
| | | | | | | | | | | |
Collapse
|
15
|
Welker E, Hathaway L, Xu G, Narayan M, Pradeep L, Shin HC, Scheraga HA. Oxidative folding and N-terminal cyclization of onconase. Biochemistry 2007; 46:5485-93. [PMID: 17439243 PMCID: PMC2535829 DOI: 10.1021/bi602495a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclization of the N-terminal glutamine residue to pyroglutamic acid in onconase, an anti-cancer chemotherapeutic agent, increases the activity and stability of the protein. Here, we examine the correlated effects of the folding/unfolding process and the formation of this N-terminal pyroglutamic acid. The results in this study indicate that cyclization of the N-terminal glutamine has no significant effect on the rate of either reductive unfolding or oxidative folding of the protein. Both the cyclized and uncyclized proteins seem to follow the same oxidative folding pathways; however, cyclization altered the relative flux of the protein in these two pathways by increasing the rate of formation of a kinetically trapped intermediate. Glutaminyl cyclase (QC) catalyzed the cyclization of the unfolded, reduced protein but had no effect on the disulfide-intact, uncyclized, folded protein. The structured intermediates of uncyclized onconase were also resistant to QC catalysis, consistent with their having a native-like fold. These observations suggest that, in vivo, cyclization takes place during the initial stages of oxidative folding, specifically, before the formation of structured intermediates. The competition between oxidative folding and QC-mediated cyclization suggests that QC-catalyzed cyclization of the N-terminal glutamine in onconase occurs in the endoplasmic reticulum, probably co-translationally.
Collapse
Affiliation(s)
- Ervin Welker
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy, H-6701, Szeged, Temesvári krt. 62. Hungary
- Institute of Enzymology of the Hungarian Academy, H-1114, Budapest, Karolina út 62. Hungary
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
| | - Laura Hathaway
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
| | - Guoqiang Xu
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
| | - Mahesh Narayan
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
| | - Lovy Pradeep
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
| | - Hang-Cheol Shin
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
| | - Harold A. Scheraga
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
- To whom correspondence should be addressed: Tel. (607) 255-4034; Fax (607) 254-4700; E-mail:
| |
Collapse
|
16
|
Buczek O, Green BR, Bulaj G. Albumin is a redox-active crowding agent that promotes oxidative folding of cysteine-rich peptides. Biopolymers 2007; 88:8-19. [PMID: 17061249 DOI: 10.1002/bip.20615] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Oxidative folding that occurs in a crowded cellular milieu is characterized by multifaceted interactions that occur among nascent polypeptides and resident components of the endoplasmic reticulum (ER) lumen. Macromolecular crowding has been considered an essential factor in the folding of polypeptides, but the excluded volume effect has not been evaluated for small, disulfide-rich peptides. In the research presented, we examined how macromolecular crowding agents, such as albumin, ovalbumin, and polysaccharides, influenced the kinetics and thermodynamics of forming disulfide bonds in four model peptides of varying molecular size from 13 residues (1.4 kDa) to 58-residues (6.5 kDa): conotoxins: GI, PVIIA, r11a, and bovine pancreatic trypsin inhibitor. Our results indicate that the excluded volume effect does not significantly alter the folding rates nor equilibria for these peptides. In stark contrast, folding reactions were dramatically accelerated, when protein-based crowding agents were present at concentrations lower than those predicted to provide the excluded volume effect. Submillimolar albumin alone was as effective as glutathione in promoting the oxidative folding of GI conotoxin at concentrations typically found in the ER. To the best of our knowledge, this is the first report and quantitative characterization of oxidative folding of peptides mediated by other than thioredoxin-based protein disulfide bonds. Our work raises a possibility that concurrent secretory and ER-resident proteins may influence the oxidative folding of small, cysteine-rich peptides not as crowding agents, but as redox-active factors.
Collapse
Affiliation(s)
- Olga Buczek
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | | | | |
Collapse
|
17
|
Peng C, Tang S, Pi C, Liu J, Wang F, Wang L, Zhou W, Xu A. Discovery of a novel class of conotoxin from Conus litteratus, lt14a, with a unique cysteine pattern. Peptides 2006; 27:2174-81. [PMID: 16797781 DOI: 10.1016/j.peptides.2006.04.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2006] [Revised: 04/02/2006] [Accepted: 04/04/2006] [Indexed: 10/24/2022]
Abstract
Conus litteratus is a worm-hunting cone snail with a highly sophisticated neuropharmacological defense strategy using small peptides in its venom. By analyzing different clones in the cDNA library of venom ducts from C. litteratus, we identified the peptide lt14a which displays a characteristic signal peptide sequence in its precursor and a unique arrangement of Cys residues (-C-C-C-C-) in its mature peptide region. RT-PCR analysis suggested that lt14a is abundantly expressed throughout the whole venom duct. An intensive analysis in sequence suggested that lt14a is similar to alpha-conotoxin qc1.1 cloned from Conus quercinus. We conducted the chemical synthesis of lt14a. The synthetic lt14a has a remarkable biological activity to suppress pain and inhibits the neuronal-type nicotinic acetylcholine receptors.
Collapse
Affiliation(s)
- Can Peng
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutic Functional Genes, The Open Laboratory for Marine Functional Genomics of State High-Tech Development Program, College of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Dy CY, Buczek P, Imperial JS, Bulaj G, Horvath MP. Structure of conkunitzin-S1, a neurotoxin and Kunitz-fold disulfide variant from cone snail. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2006; 62:980-90. [PMID: 16929098 PMCID: PMC2924234 DOI: 10.1107/s0907444906021123] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Accepted: 06/02/2006] [Indexed: 05/11/2023]
Abstract
Most Kunitz proteins like BPTI and α-dendrotoxin are stabilized by three disulfide bonds. The crystal structure shows how subtle repacking of non-covalent interactions may compensate for disulfide bond loss in a naturally occurring two-disulfide variant, conkunitzin-S1, the first discovered member of a new conotoxin family. Cone snails (Conus) are predatory marine mollusks that immobilize prey with venom containing 50–200 neurotoxic polypeptides. Most of these polypeptides are small disulfide-rich conotoxins that can be classified into families according to their respective ion-channel targets and patterns of cysteine–cysteine disulfides. Conkunitzin-S1, a potassium-channel pore-blocking toxin isolated from C. striatus venom, is a member of a newly defined conotoxin family with sequence homology to Kunitz-fold proteins such as α-dendrotoxin and bovine pancreatic trypsin inhibitor (BPTI). While conkunitzin-S1 and α-dendrotoxin are 42% identical in amino-acid sequence, conkunitzin-S1 has only four of the six cysteines normally found in Kunitz proteins. Here, the crystal structure of conkunitzin-S1 is reported. Conkunitzin-S1 adopts the canonical 310–β–β–α Kunitz fold complete with additional distinguishing structural features including two completely buried water molecules. The crystal structure, although completely consistent with previously reported NMR distance restraints, provides a greater degree of precision for atomic coordinates, especially for S atoms and buried solvent molecules. The region normally cross-linked by cysteines II and IV in other Kunitz proteins retains a network of hydrogen bonds and van der Waals interactions comparable to those found in α-dendrotoxin and BPTI. In conkunitzin-S1, glycine occupies the sequence position normally reserved for cysteine II and the special steric properties of glycine allow additional van der Waals contacts with the glutamine residue substituting for cysteine IV. Evolution has thus defrayed the cost of losing a disulfide bond by augmenting and optimizing weaker yet nonetheless effective non-covalent interactions.
Collapse
Affiliation(s)
- Catherine Y. Dy
- Biology, University of Utah, 257 S 1400 E, Salt Lake City, Utah 84112-0840, USA
| | - Pawel Buczek
- Cognetix Inc., 421 Wakara Way, Suite 201, Salt Lake City, Utah 84108, USA
| | - Julita S. Imperial
- Biology, University of Utah, 257 S 1400 E, Salt Lake City, Utah 84112-0840, USA
| | - Grzegorz Bulaj
- Biology, University of Utah, 257 S 1400 E, Salt Lake City, Utah 84112-0840, USA
- Cognetix Inc., 421 Wakara Way, Suite 201, Salt Lake City, Utah 84108, USA
| | - Martin P. Horvath
- Biology, University of Utah, 257 S 1400 E, Salt Lake City, Utah 84112-0840, USA
- Correspondence e-mail:
| |
Collapse
|
19
|
Wang SS, Chang CK, Peng MJ, Liu HS. Effect of Glutathione Redox System on Lysozyme Refolding in Size Exclusion Chromatography. FOOD AND BIOPRODUCTS PROCESSING 2006. [DOI: 10.1205/fbp.05141] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|