Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3ß4 and α7 nicotinic acetylcholine receptors.
J Biol Chem
; 295(20): 7096-7112, 2020 05 15.
Article
em En
| MEDLINE
| ID: mdl-32234761
ABSTRACT
Conopeptides are neurotoxic peptides in the venom of marine cone snails and have broad therapeutic potential for managing pain and other conditions. Here, we identified the single-disulfide peptides Czon1107 and Cca1669 from the venoms of Conus zonatus and Conus caracteristicus, respectively. We observed that Czon1107 strongly inhibits the human α3ß4 (IC50 15.7 ± 3.0 µm) and α7 (IC50 77.1 ± 0.05 µm) nicotinic acetylcholine receptor (nAChR) subtypes, but the activity of Cca1669 remains to be identified. Czon1107 acted at a site distinct from the orthosteric receptor site. Solution NMR experiments revealed that Czon1107 exists in equilibrium between conformational states that are the result of a key Ser4-Pro5cis-trans isomerization. Moreover, we found that the X-Pro amide bonds in the inter-cysteine loop are rigidly constrained to cis conformations. Structure-activity experiments of Czon1107 and its variants at positions P5 and P7 revealed that the conformation around the X-Pro bonds (cis-trans) plays an important role in receptor subtype selectivity. The cis conformation at the Cys6-Pro7 peptide bond was essential for α3ß4 nAChR subtype allosteric selectivity. In summary, we have identified a unique single-disulfide conopeptide with a noncompetitive, potentially allosteric inhibitory mechanism at the nAChRs. The small size and rigidity of the Czon1107 peptide could provide a scaffold for rational drug design strategies for allosteric nAChR modulation. This new paradigm in the "conotoxinomic" structure-function space provides an impetus to screen venom from other Conus species for similar, short bioactive peptides that allosterically modulate ligand-gated receptor function.
Palavras-chave
allosteric modulation; allosteric regulation; conformational exchange; disulfide; molecular pharmacology; nAChR receptor antagonists; neuropeptide; nicotinic acetylcholine receptors (nAChR); nuclear magnetic resonance (NMR); peptide conformation; proline cis/trans isomerism; single-disulfide conopeptides
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Receptores Nicotínicos
/
Dissulfetos
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Caramujo Conus
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Receptor Nicotínico de Acetilcolina alfa7
/
Neurotoxinas
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article