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α-Conotoxin SIA is a 13-amino-acid disulfide-rich peptide originally isolated from Conus striatus. It belongs to the classical α3/5 conotoxin family and acts as a competitive antagonist of muscle-type nicotinic acetylcholine receptors (nAChRs).
Its compact structure, defined by two intramolecular disulfide bonds and C-terminal amidation, makes SIA useful for investigating ligand recognition at neuromuscular nAChRs, receptor-interface selectivity, electrophysiological responses, and α-conotoxin structure–activity relationships.
Product Information
| Property | Specification |
|---|---|
| Product Name | α-Conotoxin SIA |
| Catalog No. | AS2585 |
| CAS No. | 135190-31-7 |
| Sequence | YCCHPACGKNFDC-NH₂ |
| Length | 13 amino acids |
| C-Terminus | Amide |
| Disulfide Connectivity | Cys2–Cys7; Cys3–Cys13 |
| Cysteine Framework | CC–C–C |
| α-Conotoxin Class | α3/5 |
| Natural Source | Conus striatus |
| Primary Target | Muscle-type nicotinic acetylcholine receptors |
| Form | Lyophilized peptide |
SIA is part of Alan Scientific's Bioactive Toxin-Derived Peptides collection for ion-channel, receptor, and neurobiology research.
nAChR Binding and Research Relevance
Muscle-type nicotinic receptors contain two acetylcholine-binding interfaces whose pharmacology can differ according to receptor composition and species. Comparative studies with SIA, GI, MI, and SI have demonstrated that closely related α-conotoxins can display substantial differences in affinity between these sites.
This characteristic makes SIA useful not simply as an nAChR blocker, but as a molecular probe for studying how receptor subunit interfaces influence ligand recognition.
Why Sequence Differences Matter
Although SIA shares the same classical CC–C–C cysteine framework with several short muscle-selective α-conotoxins, residues within its two intercysteine loops influence receptor interaction and selectivity.
For scientists developing related analogs, maintaining the intended disulfide connectivity while modifying individual loop residues provides a practical route for structure–activity studies.
Sequence and Disulfide Structure
The mature sequence is:
YCCHPACGKNFDC-NH₂
Native disulfide connectivity is Cys2–Cys7 and Cys3–Cys13. Both the C-terminal amide and native disulfide pairing should be considered when comparing synthetic material with the biologically characterized form.
Researchers investigating substitutions or related conotoxin scaffolds can use our Custom Peptide Synthesis service for sequence-specific synthesis, disulfide formation, terminal modifications, and analytical requirements.
Quality Control and Experimental Planning
For a folded peptide such as α-Conotoxin SIA, HPLC purity alone does not describe every structural attribute relevant to an experiment. Molecular identity, oxidation state, terminal amidation, and intended disulfide connectivity should be evaluated together.
Our Peptide Quality Control capabilities include analytical HPLC and mass spectrometry with batch-specific documentation according to the selected specification.
For electrophysiology or receptor-binding experiments, working concentration should be selected according to receptor composition, species, expression system, and assay conditions rather than inferred from a single literature value.
Storage and Handling
Store the lyophilized material according to the conditions specified for the supplied batch. After reconstitution, stability may depend on solvent, concentration, pH, temperature, and storage duration. Experiment-sized aliquots can help reduce unnecessary freeze–thaw exposure.
Research Use Only
α-Conotoxin SIA is supplied for research use only. It is not intended for therapeutic, or human use.