ArticleThe Biochemical journal2004
Molecular basis of the high-affinity activation of type 1 ryanodine receptors by imperatoxin A.
Article in The Biochemical journal, 2004. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 20 papers.
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Who cites it
20 citing papers in PubMed, 40 citations in OpenAlex.
- Old dog, new trick: Charybdotoxin as a novel ryanodine receptor blocker.The Journal of physiology · 2026Article
- Review
- Cryo-EM analysis of scorpion toxin binding to Ryanodine Receptors reveals subconductance that is abolished by PKA phosphorylation.Science advances · 2023Article
- A bivalent remipede toxin promotes calcium release via ryanodine receptor activation.Nature communications · 2023Article
- Article
- Recombinant expression of Intrepicalcin from the scorpion Vaejovis intrepidus and its effect on skeletal ryanodine receptors.Biochimica et biophysica acta. General subjects · 2017Article
- Toxin bioportides: exploring toxin biological activity and multifunctionality.Cellular and molecular life sciences : CMLS · 2017Review
- Structure-function relationships of peptides forming the calcin family of ryanodine receptor ligands.The Journal of general physiology · 2016Article
- Scorpion venom components that affect ion-channels function.Toxicon : official journal of the International Society on Toxinology · 2013Review
- Article
- Unique scorpion toxin with a putative ancestral fold provides insight into evolution of the inhibitor cystine knot motif.Proceedings of the National Academy of Sciences of the United States of America · 2011Article
- Both basic and acidic amino acid residues of IpTx(a) are involved in triggering substate of RyR1.Journal of biomedicine & biotechnology · 2011Article
- Imperatoxin A, a Cell-Penetrating Peptide from Scorpion Venom, as a Probe of Ca-Release Channels/Ryanodine Receptors.Pharmaceuticals (Basel, Switzerland) · 2010Article
- Characterization of hadrucalcin, a peptide from Hadrurus gertschi scorpion venom with pharmacological activity on ryanodine receptors.British journal of pharmacology · 2009Article
- Ryanoids and imperatoxin affect the modulation of cardiac ryanodine receptors by dihydropyridine receptor Peptide A.Biochimica et biophysica acta · 2008Article
- Charged surface area of maurocalcine determines its interaction with the skeletal ryanodine receptor.Biophysical journal · 2008Article
- Hemicalcin, a new toxin from the Iranian scorpion Hemiscorpius lepturus which is active on ryanodine-sensitive Ca2+ channels.The Biochemical journal · 2007Article
- Transient loss of voltage control of Ca2+ release in the presence of maurocalcine in skeletal muscle.Biophysical journal · 2006Article
- Differential effects of maurocalcine on Ca2+ release events and depolarization-induced Ca2+ release in rat skeletal muscle.The Journal of physiology · 2005Article
- Maurocalcine and domain A of the II-III loop of the dihydropyridine receptor Cav 1.1 subunit share common binding sites on the skeletal ryanodine receptor.The Journal of biological chemistry · 2005Article
Corrections and comments
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Authors and funding
9 authors at 4 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Both imperatoxin A (IpTx(a)), a 33-residue peptide toxin from scorpion venom, and peptide A, derived from the II-III loop of dihydropyridine receptor (DHPR), interact specifically with the skeletal ryanodine receptor (RyR1), which is a Ca(2+)-release channel in the sarcoplasmic reticulum, but with considerably different affinities. IpTx(a) activates RyR1 with nanomolar affinity, whereas peptide A activates RyR1 at micromolar concentrations. To investigate the molecular basis for high-affinity activation of RyR1 by IpTx(a), we have determined the NMR solution structure of IpTx(a), and identified its functional surface by using alanine-scanning analogues. A detailed comparison of the functional surface profiles for two peptide activators revealed that IpTx(a) exhibits a large functional surface area (approx. 1900 A(2), where 1 A=0.1 nm), based on a short double-stranded antiparallel beta-sheet structure, while peptide A bears a much smaller functional surface area (approx. 800 A(2)), with the five consecutive basic residues (Arg(681), Lys(682), Arg(683), Arg(684) and Lys(685)) being clustered at the C-terminal end of the alpha-helix. The functional surface of IpTx(a) is composed of six essential residues (Leu(7), Lys(22), Arg(23), Arg(24), Arg(31) and Arg(33)) and several other important residues (His(6), Lys(8), Arg(9), Lys(11), Lys(19), Lys(20), Gly(25), Thr(26), Asn(27) and Lys(30)), indicating that amino acid residues involved in RyR1 activation make up over the half of the toxin molecule with the exception of cysteine residues. Taken together, these results suggest that the site where peptide A binds to RyR1 belongs to a subset of macrosites capable of being occupied by IpTx(a), resulting in differing the affinity and the mode of activation.
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