Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models

Kryukova, Elena V.; Ivanov, Igor A.; Lebedev, Dmitry; Spirova, Ekaterina N.; Egorova, N. S.; Zouridakis, Marios; Kasheverov, Igor E.; Tzartos, Socrates J.; Tsetlin, Victor I.

doi:10.3390/md16120460

Cited by 18 publications

(15 citation statements)

References 45 publications

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“…The binding capacity (IC 50 values) was estimated in competition with the radioiodinated α-bungarotoxin [prepared as described in Kryukova et al (2018) with specific radioactivity of 500 Curies/mmol] for association with the membrane-bound Torpedo californica nAChR (Hucho et al, 1978) (kindly provided by Prof. F. Hucho, Institute for Chemistry and Biochemistry, Freie Universität Berlin, Germany), human α7 nAChR stably expressed in the rat pituitary tumor-derived cell line GH4C1 (Virginio et al, 2002) (received from Eli Lilly and Company, London, UK), LBD of the human nAChR α9 subunit (Zouridakis et al, 2014) (prepared in the laboratory of Prof. S. Tzartos, Department of Neurobiology, Hellenic Pasteur Institute, Greece), and AChBP from Aplysia californica (Lin et al, 2014) (kindly provided by Prof. S. Luo, Key Laboratory for Marine Drugs of Haikou, Hainan University, China).…”

Section: Methodsmentioning

confidence: 99%

From Synthetic Fragments of Endogenous Three-Finger Proteins to Potential Drugs

et al. 2019

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The proteins of the Ly6 family have a three-finger folding as snake venom α-neurotoxins, targeting nicotinic acetylcholine receptors (nAChRs), and some of them, like mammalian secreted Ly6/uPAR protein (SLURP1) and membrane-attached Ly-6/neurotoxin (Lynx1), also interact with distinct nAChR subtypes. We believed that synthetic fragments of these endogenous proteins might open new ways for drug design because nAChRs are well-known targets for developing analgesics and drugs against neurodegenerative diseases. Since interaction with nAChRs was earlier shown for synthetic fragments of the α-neurotoxin central loop II, we synthesized a 15-membered fragment of human Lynx1, its form with two Cys residues added at the N- and C-termini and forming a disulfide, as well as similar forms of human SLURP1, SLURP2, and of Drosophila sleepless protein (SSS). The IC 50 values measured in competition with radioiodinated α-bungarotoxin for binding to the membrane-bound Torpedo californica nAChR were 4.9 and 7.4 µM for Lynx1 and SSS fragments, but over 300 µM for SLURP1 or SLURP2 fragments. The affinity of these compounds for the α7 nAChR in the rat pituitary tumor-derived cell line GH4C1 was different: 13.1 and 147 µM for SSS and Lynx1 fragments, respectively. In competition for the ligand-binding domain of the α9 nAChR subunit, SSS and Lynx1 fragments had IC 50 values of about 40 µM, which correlates with the value found for the latter with the rat α9α10 nAChR expressed in the Xenopus oocytes. Thus, the activity of these synthetic peptides against muscle-type and α9α10 nAChRs indicates that they may be useful in design of novel myorelaxants and analgesics.

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Section: Methodsmentioning

confidence: 99%

From Synthetic Fragments of Endogenous Three-Finger Proteins to Potential Drugs

et al. 2019

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“…This means that at least relatively long oligoarginine peptides can bind to this nAChR model. We recently demonstrated a competition of 125 I-aBgt with arginine-rich a-conotoxin RgIA and aO-conotoxin GeXIVA for binding to another nAChR model, namely to the LBD of the nAChR a9 subunit (a9 LBD) (Kryukova et al, 2018a). In this work, we checked the interaction of oligoarginines with a9 LBD via their ability to inhibit specific 125 I-aBgt binding ( Fig.…”

Section: Resultsmentioning

confidence: 95%

“…In our recent work on low molecular weight compounds (Kudryavtsev et al, 2018;Spirova et al, 2019), a-conotoxins (Kudryavtsev et al, 2015;Kasheverov et al, 2016;Kryukova et al, 2018a), and human Ly6 proteins (Lyukmanova et al, 2016;Durek et al, 2017), we found that some of them can bind to the orthosteric or allosteric sites of nAChRs. Here we did not plan a detailed investigation of the mechanism of oligoarginine action, but we made exceptions for R8 and W2R4.…”

Section: Discussionmentioning

confidence: 97%

Oligoarginine Peptides, a New Family of Nicotinic Acetylcholine Receptor Inhibitors

et al. 2019

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Many peptide ligands of nicotinic acetylcholine receptors (nAChRs) contain a large number of positively charged amino acid residues, a striking example being conotoxins RgIA and GeXIVA from marine mollusk venom, with an arginine content of .30%. To determine whether peptides built exclusively from arginine residues will interact with different nAChR subtypes or with their structural homologs such as the acetylcholinebinding protein and ligand-binding domain of the nAChR a9 subunit, we synthesized a series of R3, R6, R8, and R16 oligoarginines and investigated their activity by competition with radioiodinated a-bungarotoxin, two-electrode voltageclamp electrophysiology, and calcium imaging. R6 and longer peptides inhibited muscle-type nAChRs, a7 nAChRs, and a3b2 nAChRs in the micromolar range. The most efficient inhibition of ion currents was detected for muscle nAChR by R16 (IC 50 5 157 nM) and for the a9a10 subtype by R8 and R16 (IC 50 5 44 and 120 nM, respectively). Since the R8 affinity for other tested nAChRs was 100-fold lower, R8 appears to be a selective antagonist of a9a10 nAChR. For R8, the electrophysiological and competition experiments indicated the existence of two distinct binding sites on a9a10 nAChR. Since modified oligoarginines and other cationic molecules are widely used as cell-penetrating peptides, we studied several cationic polymers and demonstrated their nAChR inhibitory activity. SIGNIFICANT STATEMENT By using radioligand analysis, electrophysiology, and calcium imaging, we found that oligoarginine peptides are a new group of inhibitors for muscle nicotinic acetylcholine receptors (nAChRs) and some neuronal nAChRs, the most active being those with 16 and 8 Arg residues. Such compounds and other cationic polymers are cell-penetrating tools for drug delivery, and we also demonstrated the inhibition of nAChRs for several of the latter. Possible positive and negative consequences of such an action should be taken into account.

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“…The α-conotoxins from the A superfamily target various subtypes of nicotinic acetylcholine receptors [ 30 , 31 , 32 ], which have a wide distribution in cone snails. Surprisingly, only three precursors of α-conotoxins Lt020, Lt021 and Lt022 with type I cysteine framework of CC-C-C were identified in C. litteratus transcriptomes, which belong to the α4/7 subfamily with CC-X4-C-X7-C mode.…”

Section: Discussionmentioning

confidence: 99%

Diversity of Conopeptides and Their Precursor Genes of Conus Litteratus

Chen

Zhangsun

et al. 2020

Marine Drugs

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The venom of various Conus species is composed of a rich variety of unique bioactive peptides, commonly referred to as conotoxins (conopeptides). Most conopeptides have specific receptors or ion channels as physiologically relevant targets. In this paper, high-throughput transcriptome sequencing was performed to analyze putative conotoxin transcripts from the venom duct of a vermivorous cone snail species, Conus litteratus native to the South China Sea. A total of 128 putative conotoxins were identified, most of them belonging to 22 known superfamilies, with 43 conotoxins being regarded as belonging to new superfamilies. Notably, the M superfamily was the most abundant in conotoxins among the known superfamilies. A total of 15 known cysteine frameworks were also described. The largest proportion of cysteine frameworks were VI/VII (C-C-CC-C-C), IX (C-C-C-C-C-C) and XIV (C-C-C-C). In addition, five novel cysteine patterns were also discovered. Simple sequence repeat detection results showed that di-nucleotide was the major type of repetition, and the codon usage bias results indicated that the codon usage bias of the conotoxin genes was weak, but the M, O1, O2 superfamilies differed in codon preference. Gene cloning indicated that there was no intron in conotoxins of the B1- or J superfamily, one intron with 1273–1339 bp existed in a mature region of the F superfamily, which is different from the previously reported gene structure of conotoxins from other superfamilies. This study will enhance our understanding of conotoxin diversity, and the new conotoxins discovered in this paper will provide more potential candidates for the development of pharmacological probes and marine peptide drugs.

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Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models

Cited by 18 publications

References 45 publications

From Synthetic Fragments of Endogenous Three-Finger Proteins to Potential Drugs

From Synthetic Fragments of Endogenous Three-Finger Proteins to Potential Drugs

Oligoarginine Peptides, a New Family of Nicotinic Acetylcholine Receptor Inhibitors

Diversity of Conopeptides and Their Precursor Genes of Conus Litteratus

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