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1.
PLoS Biol ; 21(8): e3002217, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37535677

RESUMO

Animal venom peptides represent valuable compounds for biomedical exploration. The venoms of marine cone snails constitute a particularly rich source of peptide toxins, known as conotoxins. Here, we identify the sequence of an unusually large conotoxin, Mu8.1, which defines a new class of conotoxins evolutionarily related to the well-known con-ikot-ikots and 2 additional conotoxin classes not previously described. The crystal structure of recombinant Mu8.1 displays a saposin-like fold and shows structural similarity with con-ikot-ikot. Functional studies demonstrate that Mu8.1 curtails calcium influx in defined classes of murine somatosensory dorsal root ganglion (DRG) neurons. When tested on a variety of recombinantly expressed voltage-gated ion channels, Mu8.1 displayed the highest potency against the R-type (Cav2.3) calcium channel. Ca2+ signals from Mu8.1-sensitive DRG neurons were also inhibited by SNX-482, a known spider peptide modulator of Cav2.3 and voltage-gated K+ (Kv4) channels. Our findings highlight the potential of Mu8.1 as a molecular tool to identify and study neuronal subclasses expressing Cav2.3. Importantly, this multidisciplinary study showcases the potential of uncovering novel structures and bioactivities within the largely unexplored group of macro-conotoxins.


Assuntos
Conotoxinas , Camundongos , Animais , Conotoxinas/farmacologia , Conotoxinas/química , Canais de Cálcio , Peptídeos/química , Células Receptoras Sensoriais/metabolismo , Caramujos
2.
J Biol Chem ; 300(4): 107203, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38508311

RESUMO

We are entering an exciting time in structural biology where artificial intelligence can be used to predict protein structures with greater accuracy than ever before. Extending this level of accuracy to the predictions of disulfide-rich peptide structures is likely to be more challenging, at least in the short term, given the tight packing of cysteine residues and the numerous ways that the disulfide bonds can potentially be linked. It has been previously shown in many cases that several disulfide bond connectivities can be accommodated by a single set of NMR-derived structural data without significant violations. Disulfide-rich peptides are prevalent throughout nature, and arguably the most well-known are those present in venoms from organisms such as cone snails. Here, we have determined the first three-dimensional structure and disulfide connectivity of a U-superfamily cone snail venom peptide, TxVIIB. TxVIIB has a VI/VII cysteine framework that is generally associated with an inhibitor cystine knot (ICK) fold; however, AlphaFold predicted that the peptide adopts a mini-granulin fold with a granulin disulfide connectivity. Our experimental studies using NMR spectroscopy and orthogonal protection of cysteine residues indicate that TxVIIB indeed adopts a mini-granulin fold but with the ICK disulfide connectivity. Our findings provide structural insight into the underlying features that govern formation of the mini-granulin fold rather than the ICK fold and will provide fundamental information for prediction algorithms, as the subtle complexity of disulfide isomers may be not adequately addressed by the current prediction algorithms.


Assuntos
Conotoxinas , Animais , Sequência de Aminoácidos , Conotoxinas/química , Caramujo Conus , Cisteína/química , Dissulfetos/química , Granulinas/química , Granulinas/metabolismo , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Dobramento de Proteína
3.
J Biol Chem ; 299(4): 103068, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36842500

RESUMO

µ-Conotoxin KIIIA, a selective blocker of sodium channels, has strong inhibitory activity against several Nav isoforms, including Nav1.7, and has potent analgesic effects, but it contains three pairs of disulfide bonds, making structural modification difficult and synthesis complex. To circumvent these difficulties, we designed and synthesized three KIIIA analogues with one disulfide bond deleted. The most active analogue, KIIIA-1, was further analyzed, and its binding pattern to hNav1.7 was determined by molecular dynamics simulations. Guided by the molecular dynamics computational model, we designed and tested 32 second-generation and 6 third-generation analogues of KIIIA-1 on hNav1.7 expressed in HEK293 cells. Several analogues showed significantly improved inhibitory activity on hNav1.7, and the most potent peptide, 37, was approximately 4-fold more potent than the KIIIA Isomer I and 8-fold more potent than the wildtype (WT) KIIIA in inhibiting hNav1.7 current. Intraperitoneally injected 37 exhibited potent in vivo analgesic activity in a formalin-induced inflammatory pain model, with activity reaching ∼350-fold of the positive control drug morphine. Overall, peptide 37 has a simplified disulfide-bond framework and exhibits potent in vivo analgesic effects and has promising potential for development as a pain therapy in the future.


Assuntos
Analgésicos , Conotoxinas , Canal de Sódio Disparado por Voltagem NAV1.7 , Bloqueadores do Canal de Sódio Disparado por Voltagem , Humanos , Analgésicos/farmacologia , Analgésicos/química , Conotoxinas/química , Conotoxinas/farmacologia , Dissulfetos/metabolismo , Células HEK293 , Simulação de Dinâmica Molecular , Dor/induzido quimicamente , Dor/tratamento farmacológico , Peptídeos/farmacologia , Peptídeos/metabolismo , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia
4.
Chemistry ; 30(7): e202302909, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37910861

RESUMO

Nicotinic acetylcholine receptors (nAChRs) are drug targets for neurological diseases and disorders, but selective targeting of the large number of nAChR subtypes is challenging. Marine cone snail α-conotoxins are potent blockers of nAChRs and some have been engineered to achieve subtype selectivity. This engineering effort would benefit from rapid computational methods able to predict mutational energies, but current approaches typically require high-resolution experimental structures, which are not widely available for α-conotoxin complexes. Herein, five mutational energy prediction methods were benchmarked using crystallographic and mutational data on two acetylcholine binding protein/α-conotoxin systems. Molecular models were developed for six nAChR subtypes in complex with five α-conotoxins that were studied through 150 substitutions. The best method was a combination of FoldX and molecular dynamics simulations, resulting in a predictive Matthews Correlation Coefficient (MCC) of 0.68 (85 % accuracy). Novel α-conotoxin mutants designed using this method were successfully validated by experimental assay with improved pharmaceutical properties. This work paves the way for the rapid design of subtype-specific nAChR ligands and potentially accelerated drug development.


Assuntos
Conotoxinas , Receptores Nicotínicos , Conotoxinas/química , Receptores Nicotínicos/genética , Receptores Nicotínicos/química , Receptores Nicotínicos/metabolismo , Antagonistas Nicotínicos/química , Mutação , Simulação de Dinâmica Molecular
5.
Protein Expr Purif ; 215: 106405, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37979629

RESUMO

α-Conotoxin ImI is a selective antagonist of alpha7 nicotinic acetylcholine receptor (α7 nAChR) that is involved in cancer development. Human alpha fetoprotein domain 3 (AFP3) is a prototype of anticancer agents. In an effort to design drugs for anticancer treatments, we fused the ImI peptide to AFP3 as a fusion protein for testing. The fusion protein (ImI-AFP3) was highly expressed in the insect Bac-to-Bac system. The purified fusion protein was found to have improved anticancer activity and synergized with the drug gefitinib to inhibit the growth and migration of A549 and NCI-H1299 lung cancer cells. Our data have demonstrated that the recombinant protein ImI-AFP3 is a promising candidate for drug development to suppress lung cancer cell growth, especially to suppress hepatoid adenocarcinoma of the lung (HAL) cell growth.


Assuntos
Conotoxinas , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Conotoxinas/química , Conotoxinas/metabolismo , Conotoxinas/farmacologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacologia , Pulmão
6.
J Chem Inf Model ; 64(3): 851-861, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38299978

RESUMO

As the application of molecular dynamics (MD) simulations continues to evolve, the demand for accelerating large-scale simulation systems and handling of enormous simulation tasks is steadily increasing. We propose a parallel acceleration method for large-scale MD simulations based on Sunway heterogeneous many-core processors. This method integrates task scheduling, simulation calculations, and data storage, effectively tackling issues related to large-scale simulations and numerous simulation tasks. The task scheduling strategy flexibly handles tasks on various scales and enables parallel execution of multiple tasks. During the simulation calculations, we ported GROMACS to the Sunway architecture and accelerated the calculation of short-range forces through a heterogeneous processor. Our method achieves approximately 10-fold acceleration and 90% scalability when executing a single simulation task. When handling numerous simulation tasks, our method achieves parallel execution of all of the tasks with 90% scalability. By employing our method, we carried out 50 ns simulations on over 3000 distinct conotoxin structures individually within just 5 h. Additionally, we evaluated more than 200 protein-ligand complexes, and the simulation efficiency significantly exceeded that of midsized to small GPU clusters.


Assuntos
Simulação de Dinâmica Molecular , Conotoxinas/química , Proteínas/química , Ligantes
7.
J Pept Sci ; 30(4): e3554, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38009400

RESUMO

The cysteine-free acyclic peptides present in marine cone snail venom have been much less investigated than their disulfide bonded counterparts. Precursor protein sequences derived from transcriptomic data, together with mass spectrometric fragmentation patterns for peptides present in venom duct tissue extracts, permit the identification of mature peptides. Twelve distinct gene superfamiles have been identified with precursor lengths between 64 and 158 residues. In the case of Conus monile, three distinct mature peptides have been identified, arising from two distinct protein precursors. Mature acyclic peptides are often post-translationally modified, with C-terminus amidation, a feature characteristic of neuropeptides. In the present study, 20 acyclic peptides from Conus monile and Conus betulinus were identified. The common modifications of C-terminus amidation, gamma carboxylation of glutamic acid (E to ϒ), N-terminus conversion of Gln (Q) to a pyroglutamyl residue (Z), and hydroxylation of Pro (P) to Hyp (O) are observed in one or more peptides identified in this study. Proteolytic trimming of sequences by cleavage at the C-terminus of Asn (N) residues is established. The presence of an asparagine endopeptidase is strengthened by the identification of legumain-like sequences in the transcriptome assemblies from diverse Conus species. Such sequences may be expected to have a cleavage specificity at Asn-Xxx peptide bonds.


Assuntos
Conotoxinas , Caramujo Conus , Animais , Venenos de Moluscos/química , Venenos de Moluscos/genética , Venenos de Moluscos/metabolismo , Conotoxinas/química , Peptídeos/química , Caramujo Conus/química , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo
8.
Mar Drugs ; 22(5)2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38786593

RESUMO

α7 nicotinic acetylcholine receptors (nAChRs) are mainly distributed in the central nervous system (CNS), including the hippocampus, striatum, and cortex of the brain. The α7 nAChR has high Ca2+ permeability and can be quickly activated and desensitized, and is closely related to Alzheimer's disease (AD), epilepsy, schizophrenia, lung cancer, Parkinson's disease (PD), inflammation, and other diseases. α-conotoxins from marine cone snail venom are typically short, disulfide-rich neuropeptides targeting nAChRs and can distinguish various subtypes, providing vital pharmacological tools for the functional research of nAChRs. [Q1G, ΔR14]LvΙB is a rat α7 nAChRs selective antagonist, modified from α-conotoxin LvΙB. In this study, we utilized three types of fluorescein after N-Hydroxy succinimide (NHS) activation treatment: 6-TAMRA-SE, Cy3 NHS, and BODIPY-FL NHS, labeling the N-Terminal of [Q1G, ΔR14]LvΙB under weak alkaline conditions, obtaining three fluorescent analogs: LvIB-R, LvIB-C, and LvIB-B, respectively. The potency of [Q1G, ΔR14]LvΙB fluorescent analogs was evaluated at rat α7 nAChRs expressed in Xenopus laevis oocytes. Using a two-electrode voltage clamp (TEVC), the half-maximal inhibitory concentration (IC50) values of LvIB-R, LvIB-C, and LvIB-B were 643.3 nM, 298.0 nM, and 186.9 nM, respectively. The stability of cerebrospinal fluid analysis showed that after incubation for 12 h, the retention rates of the three fluorescent analogs were 52.2%, 22.1%, and 0%, respectively. [Q1G, ΔR14]LvΙB fluorescent analogs were applied to explore the distribution of α7 nAChRs in the hippocampus and striatum of rat brain tissue and it was found that Cy3- and BODIPY FL-labeled [Q1G, ΔR14]LvΙB exhibited better imaging characteristics than 6-TAMARA-. It was also found that α7 nAChRs are widely distributed in the cerebral cortex and cerebellar lobules. Taking into account potency, imaging, and stability, [Q1G, ΔR14]LvΙB -BODIPY FL is an ideal pharmacological tool to investigate the tissue distribution and function of α7 nAChRs. Our findings not only provide a foundation for the development of conotoxins as visual pharmacological probes, but also demonstrate the distribution of α7 nAChRs in the rat brain.


Assuntos
Encéfalo , Conotoxinas , Xenopus laevis , Receptor Nicotínico de Acetilcolina alfa7 , Animais , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Conotoxinas/farmacologia , Conotoxinas/química , Ratos , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Antagonistas Nicotínicos/farmacologia , Corantes Fluorescentes , Ratos Sprague-Dawley , Masculino , Feminino
9.
Molecules ; 29(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38474693

RESUMO

Antimicrobial peptides (AMPs), acknowledged as host defense peptides, constitute a category of predominant cationic peptides prevalent in diverse life forms. This study explored the antibacterial activity of α-conotoxin RgIA, and to enhance its stability and efficacy, D-amino acid substitution was employed, resulting in the synthesis of nine RgIA mutant analogs. Results revealed that several modified RgIA mutants displayed inhibitory efficacy against various pathogenic bacteria and fungi, including Candida tropicalis and Escherichia coli. Mechanistic investigations elucidated that these polypeptides achieved antibacterial effects through the disruption of bacterial cell membranes. The study further assessed the designed peptides' hemolytic activity, cytotoxicity, and safety. Mutants with antibacterial activity exhibited lower hemolytic activity and cytotoxicity, with Pep 8 demonstrating favorable safety in mice. RgIA mutants incorporating D-amino acids exhibited notable stability and adaptability, sustaining antibacterial properties across diverse environmental conditions. This research underscores the potential of the peptide to advance innovative oral antibiotics, offering a novel approach to address bacterial infections.


Assuntos
Anti-Infecciosos , Conotoxinas , Camundongos , Animais , Lisina/farmacologia , Leucina/farmacologia , Substituição de Aminoácidos , Conotoxinas/química , Anti-Infecciosos/farmacologia , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias , Testes de Sensibilidade Microbiana
10.
Molecules ; 29(12)2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38930912

RESUMO

The escalating resistance of agricultural pests to chemical insecticides necessitates the development of novel, efficient, and safe biological insecticides. Conus quercinus, a vermivorous cone snail, yields a crude venom rich in peptides for marine worm predation. This study screened six α-conotoxins with insecticidal potential from a previously constructed transcriptome database of C. quercinus, characterized by two disulfide bonds. These conotoxins were derived via solid-phase peptide synthesis (SPPS) and folded using two-step iodine oxidation for further insecticidal activity validation, such as CCK-8 assay and insect bioassay. The final results confirmed the insecticidal activities of the six α-conotoxins, with Qc1.15 and Qc1.18 exhibiting high insecticidal activity. In addition, structural analysis via homology modeling and functional insights from molecular docking offer a preliminary look into their potential insecticidal mechanisms. In summary, this study provides essential references and foundations for developing novel insecticides.


Assuntos
Conotoxinas , Caramujo Conus , Inseticidas , Simulação de Acoplamento Molecular , Conotoxinas/química , Conotoxinas/farmacologia , Conotoxinas/síntese química , Inseticidas/química , Inseticidas/síntese química , Inseticidas/farmacologia , Animais , Caramujo Conus/química , Sequência de Aminoácidos , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/síntese química , Técnicas de Síntese em Fase Sólida/métodos
11.
Biochemistry ; 62(23): 3373-3382, 2023 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-37967580

RESUMO

α-Conotoxin GI is a competitive blocker of muscle-type acetylcholine receptors and holds the potential for being developed as a molecular probe or a lead compound for drug discovery. In this study, four fatty acid-modified α-conotoxin GI analogues of different lengths were synthesized by using a fatty acid modification strategy. Then, we performed a series of in vitro stability assays, albumin binding assays, and pharmacological activity assays to evaluate these modified mutants. The experimental results showed that the presence of fatty acids significantly enhanced the in vitro stability and albumin binding ability of α-conotoxin GI and that this effect was proportional to the length of the fatty acids used. Pharmacological activity tests showed that the modified mutants maintained a good acetylcholine receptor antagonistic activity. The present study shows that fatty acid modification can be an effective strategy to significantly improve conotoxin stability and albumin binding efficiency while maintaining the original targeting ion channel activity.


Assuntos
Conotoxinas , Receptores Nicotínicos , Receptores Nicotínicos/química , Receptores Nicotínicos/metabolismo , Sequência de Aminoácidos , Conotoxinas/farmacologia , Conotoxinas/química , Ácidos Graxos
12.
Biochemistry ; 62(21): 3061-3075, 2023 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-37862039

RESUMO

Two novel redox conopeptides with proline residues outside and within the active site disulfide loop were derived from the venom duct transcriptome of the marine cone snails Conus frigidus and Conus amadis. Mature peptides with possible post-translational modification of 4-trans-hydroxylation of proline, namely, Fr874, Fr890[P1O], Fr890[P2O], Fr906, Am1038, and Am1054, have been chemically synthesized and characterized using mass spectrometry. The estimated reduction potential of cysteine disulfides of synthetic peptides varied from -298 to -328 mV, similar to the active site cysteine disulfide motifs of the redox family of proteins. Fr906/Am1054 exhibited pronounced catalytic activity and assisted in improving the yields of natively folded globular form α-conotoxin ImI. Three-dimensional (3D) structures of the redox conopeptides were optimized using computational methods and verified by 2D-ROESY NMR spectroscopy: C. frigidus peptides adopt an N-terminal helical fold and C. amadis peptides adopt distinct structures based on the Phe4-Pro/Hyp5 peptide bond configuration. The shift in the cis-trans configuration of the Phe4-Pro/Hyp5 peptide bond of Am1038/Am1054 was observed between reduced free thiol and oxidized disulfide forms of the optimized peptides. The report confirms the position-specific effect of hydroxyproline on the oxidative folding of conotoxins and sequence diversity of redox conopeptides in the venom duct of cone snails.


Assuntos
Conotoxinas , Caramujo Conus , Animais , Transcriptoma , Peçonhas , Cisteína/metabolismo , Conotoxinas/química , Caramujo Conus/genética , Peptídeos/química , Prolina/metabolismo , Dissulfetos/metabolismo , Cistina/metabolismo , Oxirredução , Estresse Oxidativo
13.
J Biol Chem ; 298(3): 101728, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35167877

RESUMO

µ-Conotoxins are components of cone snail venom, well-known for their analgesic activity through potent inhibition of voltage-gated sodium channel (NaV) subtypes, including NaV1.7. These small, disulfide-rich peptides are typically stabilized by three disulfide bonds arranged in a 'native' CysI-CysIV, CysII-CysV, CysIII-CysVI pattern of disulfide connectivity. However, µ-conotoxin KIIIA, the smallest and most studied µ-conotoxin with inhibitory activity at NaV1.7, forms two distinct disulfide bond isomers during thermodynamic oxidative folding, including Isomer 1 (CysI-CysV, CysII-CysIV, CysIII-CysVI) and Isomer 2 (CysI-CysVI, CysII-CysIV, CysIII-CysV), but not the native µ-conotoxin arrangement. To date, there has been no study on the structure and activity of KIIIA comprising the native µ-conotoxin disulfide bond arrangement. Here, we evaluated the synthesis, potency, sodium channel subtype selectivity, and 3D structure of the three isomers of KIIIA. Using a regioselective disulfide bond-forming strategy, we synthetically produced the three µ-conotoxin KIIIA isomers displaying distinct bioactivity and NaV subtype selectivity across human NaV channel subtypes 1.2, 1.4, and 1.7. We show that Isomer 1 inhibits NaV subtypes with a rank order of potency of NaV1.4 > 1.2 > 1.7 and Isomer 2 in the order of NaV1.4≈1.2 > 1.7, while the native isomer inhibited NaV1.4 > 1.7≈1.2. The three KIIIA isomers were further evaluated by NMR solution structure analysis and molecular docking with hNaV1.2. Our study highlights the importance of investigating alternate disulfide isomers, as disulfide connectivity affects not only the overall structure of the peptides but also the potency and subtype selectivity of µ-conotoxins targeting therapeutically relevant NaV subtypes.


Assuntos
Conotoxinas , Bloqueadores do Canal de Sódio Disparado por Voltagem , Canais de Sódio Disparados por Voltagem , Conotoxinas/química , Conotoxinas/farmacologia , Dissulfetos/química , Dissulfetos/farmacologia , Humanos , Simulação de Acoplamento Molecular , Relação Estrutura-Atividade , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Canais de Sódio Disparados por Voltagem/química , Canais de Sódio Disparados por Voltagem/metabolismo
14.
Bioconjug Chem ; 34(12): 2194-2204, 2023 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-37748043

RESUMO

α6ß4* nicotinic acetylcholine receptor (nAChR) (* represents the possible presence of additional subunits) is mainly distributed in the central and peripheral nervous system and is associated with neurological diseases, such as neuropathic pain; however, the ability to explore its function and distribution is limited due to the lack of pharmacological tools. As one of the analogs of α-conotoxin (α-CTx) LvIC from Conus lividus, [D1G, Δ14Q]LvIC (Lv) selectively and potently blocks α6/α3ß4 nAChR (α6/α3 represents a chimera). Here, we synthesized three fluorescent analogs of Lv by connecting fluorescent molecules 6-carboxytetramethylrhodamine succinimidyl ester (6-TAMRA-SE, R), Cy3 NHS ester (Cy3, C) and BODIPY-FL NHS ester (BDP, B) to the N-terminus of the peptide and obtained Lv-R, Lv-C, and Lv-B, respectively. The potency and selectivity of three fluorescent peptides were evaluated using two-electrode voltage-clamp recording on nAChR subtypes expressed in Xenopus laevis oocytes, and the potency and selectivity of Lv-B were almost maintained with the half-maximal inhibition (IC50) of 64 nM. Then, we explored the stability of Lv-B in artificial cerebrospinal fluid and stained rat brain slices with Lv-B. The results indicated that the stability of Lv-B was slightly improved compared to that of native Lv. Additionally, we detected the distribution of the α6ß4* nAChR subtype in the cerebral cortex using green fluorescently labeled peptide and fluorescence microscopy. Our findings not only provide a visualized pharmacological tool for exploring the distribution of the α6ß4* nAChR subtype in various situ tissues and organs but also extend the application of α-CTx [D1G, Δ14Q]LvIC to demonstrate the involvement of α6ß4 nAChR function in pathophysiology and pharmacology.


Assuntos
Conotoxinas , Caramujo Conus , Receptores Nicotínicos , Ratos , Animais , Receptores Nicotínicos/química , Conotoxinas/química , Conotoxinas/farmacologia , Caramujo Conus/química , Peptídeos/química , Ésteres
15.
Pharmacol Res ; 191: 106747, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37001708

RESUMO

The pentameric nicotinic acetylcholine receptors (nAChRs) are typically classed as muscle- or neuronal-type, however, the latter has also been reported in non-neuronal cells. Given their broad distribution, nAChRs mediate numerous physiological and pathological processes including synaptic transmission, presynaptic modulation of transmitter release, neuropathic pain, inflammation, and cancer. There are 17 different nAChR subunits and combinations of these subunits produce subtypes with diverse pharmacological properties. The expression and role of some nAChR subtypes have been extensively deciphered with the aid of knock-out models. Many nAChR subtypes expressed in heterologous systems are selectively targeted by the disulfide-rich α-conotoxins. α-Conotoxins are small peptides isolated from the venom of cone snails, and a number of them have potential pharmaceutical value.


Assuntos
Conotoxinas , Receptores Nicotínicos , Conotoxinas/farmacologia , Conotoxinas/química , Conotoxinas/metabolismo , Receptores Nicotínicos/metabolismo , Peptídeos/farmacologia , Membrana Celular/metabolismo , Neurônios/metabolismo , Antagonistas Nicotínicos/farmacologia , Antagonistas Nicotínicos/uso terapêutico
16.
Mar Drugs ; 21(7)2023 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-37504921

RESUMO

Recombinant peptide synthesis allows for large-scale production of peptides with therapeutic potential. However, access to dicarba peptidomimetics via sidechain-deprotected sequences becomes challenging with exposed Lewis basicity presented by amine and sulfur-containing residues. Presented here is a combination of strategies which can be used to deactivate coordinative residues and achieve high-yielding Ru-catalyzed ring-closing metathesis. The chemistry is exemplified using α-conotoxin EpI, a native bicyclic disulfide-containing sequence isolated from the marine conesnail Conus episcopatus. Replacement of the loop I disulfide with E/Z-dicarba bridges was achieved with high conversion via solution-phase ring-closing metathesis of the unprotected linear peptide after simple chemoselective oxidation and ion-exchange masking of problematic functionality. Metathesis was also attempted in green solvent choices to further improve the sustainability of dicarba peptide synthesis.


Assuntos
Conotoxinas , Cistina , Peptídeos/química , Dissulfetos/química , Oxirredução , Conotoxinas/química
17.
Mar Drugs ; 21(4)2023 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-37103349

RESUMO

Marine toxins have potent actions on diverse sodium ion channels regulated by transmembrane voltage (voltage-gated ion channels) or by neurotransmitters (nicotinic acetylcholine receptor channels). Studies of these toxins have focused on varied aspects of venom peptides ranging from evolutionary relationships of predator and prey, biological actions on excitable tissues, potential application as pharmacological intervention in disease therapy, and as part of multiple experimental approaches towards an understanding of the atomistic characterization of ion channel structure. This review examines the historical perspective of the study of conotoxin peptides active on sodium channels gated by transmembrane voltage, which has led to recent advances in ion channel research made possible with the exploitation of the diversity of these marine toxins.


Assuntos
Conotoxinas , Canais de Sódio Disparados por Voltagem , Conotoxinas/farmacologia , Conotoxinas/química , Canais Iônicos , Peptídeos/farmacologia , Membrana Celular
18.
Mar Drugs ; 21(5)2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37233480

RESUMO

α4/6-conotoxin TxID, which was identified from Conus textile, simultaneously blocks rat (r) α3ß4 and rα6/α3ß4 nicotinic acetylcholine receptors (nAChRs) with IC50 values of 3.6 nM and 33.9 nM, respectively. In order to identify the effects of loop2 size on the potency of TxID, alanine (Ala) insertion and truncation mutants were designed and synthesized in this study. An electrophysiological assay was used to evaluate the activity of TxID and its loop2-modified mutants. The results showed that the inhibition of 4/7-subfamily mutants [+9A]TxID, [+10A]TxID, [+14A]TxID, and all the 4/5-subfamily mutants against rα3ß4 and rα6/α3ß4 nAChRs decreased. Overall, ala-insertion or truncation of the 9th, 10th, and 11th amino acid results in a loss of inhibition and the truncation of loop2 has more obvious impacts on its functions. Our findings have strengthened the understanding of α-conotoxin, provided guidance for further modifications, and offered a perspective for future studies on the molecular mechanism of the interaction between α-conotoxins and nAChRs.


Assuntos
Conotoxinas , Caramujo Conus , Receptores Nicotínicos , Ratos , Animais , Conotoxinas/química , Caramujo Conus/química , Receptores Nicotínicos/metabolismo , Alanina , Antagonistas Nicotínicos/farmacologia , Antagonistas Nicotínicos/química
19.
Mar Drugs ; 21(6)2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37367681

RESUMO

α-Conotoxins are well-known probes for the characterization of the various subtypes of nicotinic acetylcholine receptors (nAChRs). Identifying new α-conotoxins with different pharmacological profiles can provide further insights into the physiological or pathological roles of the numerous nAChR isoforms found at the neuromuscular junction, the central and peripheral nervous systems, and other cells such as immune cells. This study focuses on the synthesis and characterization of two novel α-conotoxins obtained from two species endemic to the Marquesas Islands, namely Conus gauguini and Conus adamsonii. Both species prey on fish, and their venom is considered a rich source of bioactive peptides that can target a wide range of pharmacological receptors in vertebrates. Here, we demonstrate the versatile use of a one-pot disulfide bond synthesis to achieve the α-conotoxin fold [Cys 1-3; 2-4] for GaIA and AdIA, using the 2-nitrobenzyl (NBzl) protecting group of cysteines for effective regioselective oxidation. The potency and selectivity of GaIA and AdIA against rat nicotinic acetylcholine receptors were investigated electrophysiologically and revealed potent inhibitory activities. GaIA was most active at the muscle nAChR (IC50 = 38 nM), whereas AdIA was most potent at the neuronal α6/3 ß2ß3 subtype (IC50 = 177 nM). Overall, this study contributes to a better understanding of the structure-activity relationships of α-conotoxins, which may help in the design of more selective tools.


Assuntos
Conotoxinas , Caramujo Conus , Receptores Nicotínicos , Animais , Ratos , Conotoxinas/farmacologia , Conotoxinas/química , Caramujo Conus/química , Caramujo Conus/fisiologia , Antagonistas Nicotínicos/farmacologia , Caramujos , Polinésia
20.
Mar Drugs ; 21(3)2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36976203

RESUMO

The venom of marine cone snails is mainly composed of peptide toxins called conopeptides, among which conotoxins represent those that are disulfide-rich. Publications on conopeptides frequently state that conopeptides attract considerable interest for their potent and selective activity, but there has been no analysis yet that formally quantifies the popularity of the field. We fill this gap here by providing a bibliometric analysis of the literature on cone snail toxins from 2000 to 2022. Our analysis of 3028 research articles and 393 reviews revealed that research in the conopeptide field is indeed prolific, with an average of 130 research articles per year. The data show that the research is typically carried out collaboratively and worldwide, and that discoveries are truly a community-based effort. An analysis of the keywords provided with each article revealed research trends, their evolution over the studied period, and important milestones. The most employed keywords are related to pharmacology and medicinal chemistry. In 2004, the trend in keywords changed, with the pivotal event of that year being the approval by the FDA of the first peptide toxin drug, ziconotide, a conopeptide, for the treatment of intractable pain. The corresponding research article is among the top ten most cited articles in the conopeptide literature. From the time of that article, medicinal chemistry aiming at engineering conopeptides to treat neuropathic pain ramped up, as seen by an increased focus on topological modifications (e.g., cyclization), electrophysiology, and structural biology.


Assuntos
Conotoxinas , Caramujo Conus , Animais , Caramujo Conus/química , Conotoxinas/farmacologia , Conotoxinas/química , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Peptídeos/química , Caramujos
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