Single Amino Acid Substitutions in κ-Conotoxin PVIIA Disrupt Interaction with the Shaker K+ Channel

Jacobsen, Richard B.; Koch, E. Dietlind; Lange-Malecki, Bettina; Stocker, Martin; Verhey, Janko F; Wagoner, Ryan M. Van; Vyazovkina, Alexandra; Olivera, Baldomero M.; Terlau, Heinrich

doi:10.1074/jbc.c900990199

Cited by 60 publications

(99 citation statements)

References 28 publications

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“…1A). Sea Anemone-Sea anemones also have yielded a diversity of K ϩ channel peptide inhibitors classified into three main types (15 (20). A model of the -conotoxin PVIIA-Shaker K ϩ channel complex showed a reasonable correlation with experimental data (Fig.…”

Section: Potassium Channel Toxinsmentioning

confidence: 56%

Use of Venom Peptides to Probe Ion Channel Structure and Function

Dutertre

Lewis

2010

Journal of Biological Chemistry

150

110

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Venoms of snakes, scorpions, spiders, insects, sea anemones, and cone snails are complex mixtures of mostly peptides and small proteins that have evolved for prey capture and/or defense. These deadly animals have long fascinated scientists and the public. Early studies isolated lethal components in the search for cures and understanding of their mechanisms of action. Ion channels have emerged as targets for many venom peptides, providing researchers highly selective and potent molecular probes that have proved invaluable in unraveling ion channel structure and function. This minireview highlights molecular details of their toxin-receptor interactions and opportunities for development of peptide therapeutics.

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Section: Potassium Channel Toxinsmentioning

confidence: 56%

Use of Venom Peptides to Probe Ion Channel Structure and Function

Dutertre

Lewis

2010

Journal of Biological Chemistry

150

110

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“…5C). Similar overlays (not shown) can be made with the functionally critical diad residues in numerous other K ϩ channel blockers such as charybdotoxin (44) and -conotoxin PVIIA (45). Thus, although the three-dimensional fold of J-ACTX-Hv1c is homologous to the sodium channel modulators conotoxin GS, -agatoxin-I, and ␦-ACTX-Hv1a (12), the hot spot identified by site-directed mutagenesis provides circumstantial evidence that the J-ACTXs might target invertebrate K ϩ channels.…”

Section: Discussionmentioning

confidence: 97%

Scanning Mutagenesis of a Janus-faced Atracotoxin Reveals a Bipartite Surface Patch That Is Essential for Neurotoxic Function

Maggio¹,

King²

2002

Journal of Biological Chemistry

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The Janus-faced atracotoxins (J-ACTXs) are a family of insect-specific excitatory neurotoxins isolated from the venom of Australian funnel web spiders. In addition to a strikingly asymmetric distribution of charged residues, from which their name is derived, these toxins contain an extremely rare vicinal disulfide bond. To shed light on the mechanism of action of these toxins and to enhance their utility as lead compounds for insecticide development, we developed a recombinant expression system for the prototypic family member, J-ACTX-Hv1c, and mapped the key functional residues using site-directed mutagenesis. An alanine scan using a panel of 24 mutants provided the first complete map of the bioactive surface of a spider toxin and revealed that the entire J-ACTX-Hv1c pharmacophore is restricted to seven residues that form a bipartite surface patch on one face of the toxin. However, the primary pharmacophore, or hot spot, is formed by just five residues (Arg 8 , Pro 9 , Tyr 31 , and the Cys 13 -Cys 14 vicinal disulfide). The Arg 8 -Tyr 31 diad in J-ACTX-Hv1c superimposes closely on the Lys-(Tyr/Phe) diad that is spatially conserved across a range of structurally dissimilar K ؉ channel blockers, which leads us to speculate that the JACTXs might target an invertebrate K ؉ channel.As well as destroying an estimated 20 -30% of the world's food supply (1), arthropod pests are responsible for the transmission of numerous human diseases. Mosquitoes, for example, transmit dengue fever, yellow fever, West Nile virus, filariasis, and malaria, with malaria causing more than two million deaths annually (2). These phytophagous and hematophagous insect pests have traditionally been controlled by spraying broad spectrum chemical pesticides. However, the emergence of insecticide-resistant insect populations (3, 4), as well as increasing concerns about the environmental and human health risks associated with certain chemical pesticides (5, 6), has stimulated the search for new pest control strategies.The pioneering work of Olivera and colleagues (7, 8) has revealed that the venoms of aquatic cone snails (Conus spp.) are essentially highly evolved combinatorial peptide libraries. We have argued that spider venoms can be analogously viewed as preoptimized combinatorial libraries of insecticidal compounds (9), and therefore we decided to exploit these venoms in the search for insect-specific peptide toxins. By screening the venom of the lethal funnel web spider Hadronyche versuta (10), we discovered three families of insect-specific toxins (9,11,12), including an unusual family of excitatory neurotoxins that we named the Janus-faced atracotoxins (J-ACTXs; Fig. 1).1 In addition to being excellent biopesticide candidates, these toxins have allowed validation of new insecticide targets, and consequently they could be invaluable leads for the development of novel chemical insecticides (13).In addition to a strikingly asymmetric distribution of charged residues, from which the toxin name is derived, the J-ACTXs contain an extremely rare...

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“…With the use of alanine-scanning mutagenesis, the interaction surface of -PVIIA with the Shaker channel pore has been identified. Mutations within the P-loop of the channel protein have major effects on the binding of -PVIIA (169); a double mutant cycling analysis revealed that -PVIIA, like other K channel blocking peptides, contains a critical dyad motif of amino acids important for K channel blockade (78). This dyad consists of lysine-7 and a phenylalanine-9, which are ϳ6 Å apart.…”

Section: -Conotoxinsmentioning

confidence: 99%

ConusVenoms: A Rich Source of Novel Ion Channel-Targeted Peptides

Terlau

Olivera

2004

Physiological Reviews

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861

828

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Terlau, Heinrich, and Baldomero M. Olivera. Conus Venoms: A Rich Source of Novel Ion Channel-Targeted Peptides. Physiol Rev 84: 41–68, 2004; 10.1152/physrev.00020.2003.—The cone snails (genus Conus) are venomous marine molluscs that use small, structured peptide toxins (conotoxins) for prey capture, defense, and competitor deterrence. Each of the 500 Conus can express ∼100 different conotoxins, with little overlap between species. An overwhelming majority of these peptides are probably targeted selectively to a specific ion channel. Because conotoxins discriminate between closely related subtypes of ion channels, they are widely used as pharmacological agents in ion channel research, and several have direct diagnostic and therapeutic potential. Large conotoxin families can comprise hundreds or thousands of different peptides; most families have a corresponding ion channel family target (i.e., ω-conotoxins and Ca channels, α-conotoxins and nicotinic receptors). Different conotoxin families may have different ligand binding sites on the same ion channel target (i.e., μ-conotoxins and δ-conotoxins to sites 1 and 6 of Na channels, respectively). The individual peptides in a conotoxin family are typically each selectively targeted to a diverse set of different molecular isoforms within the same ion channel family. This review focuses on the targeting specificity of conotoxins and their differential binding to different states of an ion channel.

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Single Amino Acid Substitutions in κ-Conotoxin PVIIA Disrupt Interaction with the Shaker K+ Channel

Cited by 60 publications

References 28 publications

Use of Venom Peptides to Probe Ion Channel Structure and Function

Use of Venom Peptides to Probe Ion Channel Structure and Function

Scanning Mutagenesis of a Janus-faced Atracotoxin Reveals a Bipartite Surface Patch That Is Essential for Neurotoxic Function

ConusVenoms: A Rich Source of Novel Ion Channel-Targeted Peptides

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