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Chemical and functional identification and characterization of novel sulfated alpha-conotoxins from the cone snail Conus anemone.
- Source :
-
Journal of medicinal chemistry [J Med Chem] 2004 Feb 26; Vol. 47 (5), pp. 1234-41. - Publication Year :
- 2004
-
Abstract
- An LC/MS analysis with diagnostic screening for the detection of peptides with posttranslational modifications revealed the presence of novel sulfated peptides within the alpha-conotoxin molecular mass range in Conus anemone crude venom. A functional assay of the extract showed activity at several neuronal nicotinic acetylcholine receptors (nAChRs). Three sulfated alpha-conotoxins (AnIA, AnIB, and AnIC) were identified by LC/MS and assay-directed fractionation and sequenced after purification. The most active of these, alpha-AnIB, was further characterized and used to investigate the influence of posttranslational modifications on affinity. Synthetic AnIB exhibited subnanomolar potency at the rat alpha3beta2 nAChR (IC50 0.3 nM) and was 200-fold less active on the rat alpha7 nAChR (IC50 76 nM). The unsulfated peptide [Tyr16]AnIB showed a 2-fold and 10-fold decrease in activities at alpha3beta2 (IC50 0.6 nM) and alpha7 (IC50 836 nM) nAChR, respectively. Likewise, removal of the C-terminal amide had a greater influence on potency at the alpha7 (IC50 367 nM) than at the alpha3beta2 nAChR (IC50 0.5 nM). Stepwise removal of two N-terminal glycine residues revealed that these residues affect the binding kinetics of the peptide. Comparison with similar 4/7-alpha-conotoxin sequences suggests that residue 11 (alanine or glycine) and residue 14 (glutamine) constitute important determinants for alpha3beta2 selectivity, whereas the C-terminal amidation and sulfation at tyrosine-16 favor alpha7 affinity.
- Subjects :
- Animals
Cholinergic Antagonists chemistry
Cholinergic Antagonists isolation & purification
Cholinergic Antagonists pharmacology
Chromatography, Liquid
Conotoxins pharmacology
In Vitro Techniques
Mass Spectrometry
Neurons metabolism
Oligopeptides chemical synthesis
Oligopeptides chemistry
Oligopeptides pharmacology
Oocytes metabolism
Oocytes physiology
Patch-Clamp Techniques
Protein Subunits
Rats
Receptors, Nicotinic drug effects
Structure-Activity Relationship
Xenopus
Conotoxins chemistry
Conotoxins isolation & purification
Mollusk Venoms chemistry
Snails chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 0022-2623
- Volume :
- 47
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Journal of medicinal chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 14971903
- Full Text :
- https://doi.org/10.1021/jm031010o