Binding Site and Inhibitory Mechanism of the Mambalgin-2 Pain-relieving Peptide on Acid-sensing Ion Channel 1a

Salinas, Miguel; Besson, Thomas; Delettre, Quentin; Diochot, Sylvie; Boulakirba, Sonia; Douguet, Dominique; Lingueglia, Éric

doi:10.1074/jbc.m114.561076

Cited by 53 publications

(69 citation statements)

References 43 publications

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“…This provides the experimental confirmation that finger II is crucial for interaction with ASIC1a, as suggested in the ASIC1a-mambalgin initial model we previously described (10). A loss of inhibitory effect was observed with wild-type mambalgin on the mutant channel rASIC1a-Phe-350, suggesting that residue Phe-350, located near the acidic pocket in ASIC1a, could be involved in the binding surface with the toxin (10).…”

Section: Discussionsupporting

confidence: 60%

“…However, mambalgin-1 analogues H21A, T23A, N29A, L30A, K31A, and K57A share more or less the same affinity for ASIC1a channel than the wild-type toxin (less than 5-fold decrease in affinity) ( Table 4). These data support the interaction of finger II with ASIC1a channel but on a face different from the one initially predicted from the docking of mambalgin (NMR structure) onto the channel (10) where no binding constraints were applied. Mambalgin-1 and Phe-350 in ASIC1a-Inhibition of the ASIC1a-F350L mutant channel by sMamb-1 variants F27A, L32A, and L34A has been analyzed to address the possible proximity of these residues located into the hydrophobic region of the toxin, with Phe-350 in ASIC1a, which is located near the acidic pocket of the channel and has been shown to be important for the toxin interaction (10).…”

Section: Alanine Scanning Confirms the Role Of Finger II And Identifimentioning

confidence: 49%

“…7) and sMamb-1/ASIC1aF350L are shown in all panels. Therefore, although sharing some features, these results highlight differences in the inhibitory mechanisms of mambalgin-1 and PcTx1 on the ASIC1a channel (10). These data clearly identify the binding face of mambalgin-1 on ASIC channels and the crucial role of toxin's loop II (and more particularly Leu-32) in this interaction.…”

Section: Discussionmentioning

confidence: 69%

“…Mambalgins act as gating modifiers that bind to the closed state of the channel and induce a strong shift of the pH-dependent activation of ASIC1a channel toward more acidic pH, decreasing its apparent affinity for protons (1). The binding site on ASIC channels and the inhibitory mechanism of these peptides have been recently identified (10). Mambalgins bind into the acidic pocket of the extracellular domain of ASIC1a and have been proposed to block the channel by a pH sensor-trapping mechanism.…”

mentioning

confidence: 99%

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Mambalgin-1 Pain-relieving Peptide, Stepwise Solid-phase Synthesis, Crystal Structure, and Functional Domain for Acid-sensing Ion Channel 1a Inhibition

Mourier

Salinas

Kessler

et al. 2016

Journal of Biological Chemistry

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Mambalgins are peptides isolated from mamba venom that specifically inhibit a set of acid-sensing ion channels (ASICs) to relieve pain. We show here the first full stepwise solid phase peptide synthesis of mambalgin-1 and confirm the biological activity of the synthetic toxin both in vitro and in vivo. We also report the determination of its three-dimensional crystal structure showing differences with previously described NMR structures. Finally, the functional domain by which the toxin inhibits ASIC1a channels was identified in its loop II and more precisely in the face containing Phe-27, Leu-32, and Leu-34 residues. Moreover, proximity between Leu-32 in mambalgin-1 and Phe-350 in rASIC1a was proposed from double mutant cycle analysis. These data provide information on the structure and on the pharmacophore for ASIC channel inhibition by mambalgins that could have therapeutic value against pain and probably other neurological disorders.

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Section: Discussionsupporting

confidence: 60%

Section: Alanine Scanning Confirms the Role Of Finger II And Identifimentioning

confidence: 49%

Section: Discussionmentioning

confidence: 69%

mentioning

confidence: 99%

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Mambalgin-1 Pain-relieving Peptide, Stepwise Solid-phase Synthesis, Crystal Structure, and Functional Domain for Acid-sensing Ion Channel 1a Inhibition

Mourier

Salinas

Kessler

et al. 2016

Journal of Biological Chemistry

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“…The AcP is the binding site of the two gating modifier toxins PcTx1 and Mambalgin (7,9,(25)(26)(27). Nonconservative mutations in the AcP of ASICs have induced strong changes in the pH dependence (11,28), whereas conservative mutations of Asp and Glu residues induced modest (5,12) or no changes in activation pH dependence (10).…”

Section: Discussionmentioning

confidence: 99%

Conformational dynamics and role of the acidic pocket in ASIC pH-dependent gating

Vullo

Bonifacio

Roy

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Acid-sensing ion channels (ASICs) are proton-activated Na + channels expressed in the nervous system, where they are involved in learning, fear behaviors, neurodegeneration, and pain sensation. In this work, we study the role in pH sensing of two regions of the ectodomain enriched in acidic residues: the acidic pocket, which faces the outside of the protein and is the binding site of several animal toxins, and the palm, a central channel domain. Using voltage clamp fluorometry, we find that the acidic pocket undergoes conformational changes during both activation and desensitization. Concurrently, we find that, although proton sensing in the acidic pocket is not required for channel function, it does contribute to both activation and desensitization. Furthermore, protonationmimicking mutations of acidic residues in the palm induce a dramatic acceleration of desensitization followed by the appearance of a sustained current. In summary, this work describes the roles of potential pH sensors in two extracellular domains, and it proposes a model of acidification-induced conformational changes occurring in the acidic pocket of ASIC1a.

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From the Sequence to the Conformation of the Unabridged Transmembrane Domains TM1 and TM2 of the cASIC1a Ion Channel – A Parallel Tempering Approach

Pietra

2015

Chemistry & Biodiversity

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This work was devised to unravel, along replica-exchange molecular-dynamics (REMD) simulations, the conformation in solution of the TM1 and TM2 transmembrane domains of the homotrimeric cASIC1a ion channel. This includes the head of TM1 and tail of TM2 that had previously defied X-ray diffraction analysis in the crystal. The structure of the open-channel complex of cASIC1a with psalmotoxin 1 (PcTx1) was chosen here as a basis, although, to make the simulations affordable, the procedure was limited to the missing portions, including a few adjacent α-helical turns. The latter were held fixed during the simulations. Reassembling the whole subunit, by superimposition of the fixed portions, resulted in diving of both TM1 and TM2 as continuous α-helices into the cytoplasm. At completion of this work, it appeared, from similar X-ray diffraction studies, that TM2 for both the complex of cASIC1a with the coral snake MitTx toxin, and the isolated desensitized ion channel, is discontinuous, with the triad G443-A444-S445 taking an extended, belt-like conformation. In this way, a filter ring against hydrated ions is formed by G443 in the trimer. Our REMD examination of this complex revealed a strong resistance by G443, and only that residue, to take dihedral-angle values compatible with an α-helical conformation. This suggests that the flexibility of glycine alone does not explain formation of the extended, belt-like conformation of the triad G443-A444-S445. This also requires cooperation in the trimer.

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Binding Site and Inhibitory Mechanism of the Mambalgin-2 Pain-relieving Peptide on Acid-sensing Ion Channel 1a

Cited by 53 publications

References 43 publications

Mambalgin-1 Pain-relieving Peptide, Stepwise Solid-phase Synthesis, Crystal Structure, and Functional Domain for Acid-sensing Ion Channel 1a Inhibition

Mambalgin-1 Pain-relieving Peptide, Stepwise Solid-phase Synthesis, Crystal Structure, and Functional Domain for Acid-sensing Ion Channel 1a Inhibition

Conformational dynamics and role of the acidic pocket in ASIC pH-dependent gating

From the Sequence to the Conformation of the Unabridged Transmembrane Domains TM1 and TM2 of the cASIC1a Ion Channel – A Parallel Tempering Approach

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