Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3β4 and α7 nicotinic acetylcholine receptors
peer-reviewed · Journal of Biological Chemistry · 2020
| Date | 2020-05-01 |
| Type | peer-reviewed |
| Venue | Journal of Biological Chemistry |
| Publisher | Elsevier BV |
| Contribution | downstream-application |
| DOI | 10.1074/jbc.ra119.012098 |
| Citations (OpenAlex) | 12 |
| Venue 2-year citedness | 1.83 |
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 α3β4 (IC 50 15.7 ± 3.0 μm) and α7 (IC 50 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 Ser 4 -Pro 5 cis-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 Cys 6 -Pro 7 peptide bond was essential for α3β4 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.
Methods and tools
- Conus zonatus single-disulfide conopeptide Czon1107: Identifies and de novo sequences single-disulfide conopeptides from Conus zonatus and Conus caracteristicus venom using MSn of native and derivatized peptides, then shows Czon1107 allosterically inhibits human nicotinic receptors.
Data deposited
- Identification and characterization of novel peptide components in the venom of Indian marine cone snails — as deposited · PXD017882