OmIA (P00006) Protein Card

General Information
Name OmIA
Alternative name(s) Om1a
Organism Conus omaria
Organism region Indo-Pacific
Organism diet molluscivorous
Protein Type Wild type

Classification
Conopeptide class conotoxin
Gene superfamily A superfamily
Cysteine framework I
Pharmacological family alpha conotoxin

Sequence
GCCSHPACNVNNPHICG(nh2)
Modified residues
positionsymbolname
18nh2C-term amidation
Sequence evidence protein level
Average Mass 1720.93
Monoisotopic Mass 1719.65
Isoelectric Point 8.42
Extinction Coefficient [280nm] NA

Activity

IC50: Nicotinic acetylcholine receptors

TargetOrganismIC50nhillAgonistRef
α1β1δεM. musculus>10uM10uM AchTalley,T.T. et al. (2006)
α2β2R. norvegicus>10uM100uM AchTalley,T.T. et al. (2006)
α3β2R. norvegicus11.0nM+/-6100nM AchTalley,T.T. et al. (2006)
α3β4H. sapiens0.16 uM+/-0.0330 uM cholineHo,T.N.T. et al. (2021)
R. norvegicus>10uM100nM AchTalley,T.T. et al. (2006)
α4β2R. norvegicus>10uM100nM AchTalley,T.T. et al. (2006)
α6/α3β2R. norvegicus201nM+/-100100nM AchTalley,T.T. et al. (2006)
α7H. sapiens290 nM[240-340]1.2200uM AchYu et al. (2018)
0.27 uM+/-0.0230uM cholineHo,T.N.T. et al. (2021)
(TQS (10 uM))0.50 uM+/-0.0930 uM cholineHo,T.N.T. et al. (2021)
R. norvegicus59 nM[51-69]1.2200uM AchYu et al. (2018)
27.1nM+/-12200uM AchTalley,T.T. et al. (2006)

Ki: Nicotinic acetylcholine receptors

TargetOrganismKiCompetitorAgonistRef
AChBPL. stagnalis0.28 uM+/-0.07[3H]-epibatidine (1nM)Ho,T.N.T. et al. (2021)

Synthetic variants
OmIA[H5R]GCCSRPACNVNNPHICG(nh2)
OmIA[N11D]GCCSHPACNVDNPHICG(nh2)
OmIA[N9H]GCCSHPACHVNNPHICG(nh2)
OmIA[V10Q]GCCSHPACNQNNPHICG(nh2)

References
Talley,T.T., Olivera,B.M., Han,K.H., Christensen,S.B., Dowell,C., Tsigelny,I., Ho,K.Y., Taylor,P. and McIntosh,J.M. (2006) Alpha-conotoxin OmIA is a potent ligand for the acetylcholine-binding protein as well as alpha3beta2 and alpha7 nicotinic acetylcholine receptors J. Biol. Chem. 281:24678-24686
Chi,S.W., Kim,D.H., Olivera,B.M., McIntosh,J.M. and Han,K.H. (2006) Solution conformation of a neuronal nicotinic acetylcholine receptor antagonist alpha-conotoxin OmIA that discriminates alpha3 vs. alpha6 nAChR subtypes Biochem. Biophys. Res. Commun. 345:248-254
Yu, J., Zhu, X., Zhang, L., Kudryavtsev, D., Kasheverov, I., Lei, Y., Zhangsun, D., Tsetlin, V. and Luo, S. (2018) Species specificity of rat and human α7 nicotinic acetylcholine receptors towards different classes of peptide and protein antagonists Neuropharmacology 139:226-237
Ho,T.N.T., Abraham,N., Lewis,R.J. (2021) Unique Pharmacological Properties of α-Conotoxin OmIA at α7 nAChRs. Front Pharmacol 12:803397

Internal links
Nucleic acids
Structure SOLUTION STRUCTURE OF ALPHA-CONOTOXIN OMIA
Alpha-conotoxin OmIA with unusual pharmacological properties at alpha7 nicotinic receptors

External links
UniProtKB/Swiss-Prot P0C1R7
Ncbi 2GCZ_A, P0C1R7

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