Virtual screening against alpha-cobratoxin.

Area of Science:

• Neuroscience
• Pharmacology
• Biochemistry

Background:

• Alpha-cobratoxin (Cbtx) from Naja kaouthia venom causes paralysis by blocking acetylcholine binding to nicotinic acetylcholine receptors (nAChRs).
• Developing effective anticobratoxin drugs is crucial for treating neurotoxic envenomation.

Purpose of the Study:

• To identify novel drug candidates targeting the Cbtx binding site on nAChRs for anticobratoxin drug design.
• To utilize the crystal structure of Cbtx complexed with acetylcholine binding protein (AChBP) for virtual screening.

Main Methods:

• Virtual screening of the National Cancer Institute diversity set against the Cbtx active site using AutoDock.
• In vitro radioligand competition assays using radiolabeled ligands and AChBPs from various species.
• In vivo studies to evaluate the efficacy of identified inhibitors in prolonging survival time in mice.

Main Results:

• Virtual screening identified 39 potential inhibitor candidates.
• Four compounds demonstrated micromolar to nanomolar interference with Cbtx binding to AChBPs.
• Three compounds (NSC42258, NSC121865, NSC134754) prolonged mouse survival post-Cbtx injection, with NSC121865 and NSC134754 effective even when administered immediately after envenomation.

Conclusions:

• Identified novel small molecules as potential scaffolds for developing potent and specific anticobratoxin therapeutics.
• Demonstrated the feasibility of structure-based drug design targeting Cbtx-nAChR interactions.
• Highlighted the therapeutic potential of identified compounds in mitigating Cbtx-induced paralysis and improving survival outcomes.