Characterization of α-conotoxin interactions with the nicotinic acetylcholine receptor and monoclonal antibodies

Abstract

The venoms of predatory marine cone snails, Conus species, contain numerous peptides and proteins with remarkably diverse pharmacological properties. One group of peptides are the alpha-conotoxins, which consist of 13-19 amino acids constrained by two disulphide bonds. A biologically active fluorescein derivative of Conus geographus alpha-conotoxin GI (FGI) was used in novel solution-phase-binding assays with purified Torpedo californica nicotinic acetylcholine receptor (nAchR) and monoclonal antibodies developed against the toxin. The binding of FGI to nAchR or antibody had apparent dissociation constants of 10-100 nM. Structure-function studies with alpha-conotoxin GI analogues composed of a single disulphide loop revealed that different conformational restraints are necessary for effective toxin interactions with nAchR or antibodies.

Localization of agonist and competitive antagonist binding sites on nicotinic acetylcholine receptors

“…These studies have provided support for the idea that these small triangular polypeptides achieve their wedge-like structure and conformational stability by means of disul®de bonding. This and other conformational restraints have been found to be necessary for eective a-CoTx interactions with the AChR (Ashcom and Stiles, 1997).…”

Proteomic Methods of Detection and Quantification of Protein Toxins

“…The method developed for purified α-conotoxin GI in phosphate buffer was published [ 226 ]. In this method, a biologically active fluorescein derivative of Conus geographus α-conotoxin (FGI) was used in solution-phase-binding assays with two purified mAbs to detect the toxin in laboratory samples.…”

Highly Enantioselective Synthesis of N‐Protected β‐Amino Malonates Catalyzed by Magnetically Separable Heterogeneous Rosin‐Derived Amino Thiourea Catalysts: A Stereocontrolled Approach to β‐Amino Acids

“…6 Ligand binding to nAChRs is usually investigated by competition assays that either use radiolabeled or fluorescently labeled α‐bungarotoxin (α‐BgTx); this is a ligand that binds irreversibly to homopentameric α7, α9, α10, and muscle nAChRs. So far, only a few fluorescent ligands that bind reversibly to nAChRs have been identified 7–11. These comprise fluorophores that have weak fluorescence properties and are unsuitable for cellular measurements.…”