AbeTx1 is a novel sea anemone toxin with a dual mechanism of action on Shaker-type K+ channels activation
Orts, D.J.B.; Peigneur, S.; Silva-Goncalves, L.C.; Arcisio-Miranda, M.; Bicudo, J.E.P.W.; Tytgat, J. (2018). AbeTx1 is a novel sea anemone toxin with a dual mechanism of action on Shaker-type K+ channels activation. Mar. Drugs 16(10): 360. https://dx.doi.org/10.3390/md16100360 In: Marine Drugs. Molecular Diversity Preservation International (MDPI): Basel. ISSN 1660-3397; e-ISSN 1660-3397, more |   |
| Keywords | Actinia bermudensis (McMurrich, 1889) [WoRMS]
Marine/Coastal | | Author keywords | sea anemone neurotoxin; Actinia bermudensis; potassium channel; type 6K-V-toxins; Alanine point mutation |
| Authors | | Top | - Orts, D.J.B.
- Peigneur, S., more
- Silva-Goncalves, L.C.
| - Arcisio-Miranda, M.
- Bicudo, J.E.P.W.
- Tytgat, J., more
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| Abstract | Voltage-gated potassium (KV) channels regulate diverse physiological processes and are an important target for developing novel therapeutic approaches. Sea anemone (Cnidaria, Anthozoa) venoms comprise a highly complex mixture of peptide toxins with diverse and selective pharmacology on KV channels. From the nematocysts of the sea anemone Actinia bermudensis, a peptide that we named AbeTx1 was purified and functionally characterized on 12 different subtypes of KV channels (KV1.1–KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; KV11.1; and, Shaker IR), and three voltage-gated sodium channel isoforms (NaV1.2, NaV1.4, and BgNaV). AbeTx1 was selective for Shaker-related K+ channels and is capable of inhibiting K+ currents, not only by blocking the K+ current of KV1.2 subtype, but by altering the energetics of activation of KV1.1 and KV1.6. Moreover, experiments using six synthetic alanine point-mutated analogs further showed that a ring of basic amino acids acts as a multipoint interaction for the binding of the toxin to the channel. The AbeTx1 primary sequence is composed of 17 amino acids with a high proportion of lysines and arginines, including two disulfide bridges (Cys1–Cys4 and Cys2–Cys3), and it is devoid of aromatic or aliphatic amino acids. Secondary structure analysis reveals that AbeTx1 has a highly flexible, random-coil-like conformation, but with a tendency of structuring in the beta sheet. Its overall structure is similar to open-ended cyclic peptides found on the scorpion κ-KTx toxins family, cone snail venoms, and antimicrobial peptides. |
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