{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T01:45:13Z","timestamp":1784771113359,"version":"3.55.0"},"reference-count":51,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2024,9,28]],"date-time":"2024-09-28T00:00:00Z","timestamp":1727481600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Pasteur Institute, Ministry of Health &amp; Ministry of High Education and Scientific Research of Tunisia","award":["LR11IPT08"],"award-info":[{"award-number":["LR11IPT08"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Maurotoxin (MTX) is a 34-residue peptide from Scorpio maurus venom. It is reticulated by four disulfide bridges with a unique arrangement compared to other scorpion toxins that target potassium (K+) channels. Structure\u2013activity relationship studies have not been well performed for this toxin family. The screening of Scorpio maurus venom was performed by different steps of fractionation, followed by the ELISA test, using MTX antibodies, to isolate an MTX-like peptide. In vitro, in vivo and computational studies were performed to study the structure\u2013activity relationship of the new isolated peptide. We isolated a new peptide designated MTX1, structurally related to MTX. It demonstrated toxicity on mice eight times more effectively than MTX. MTX1 blocks the Kv1.2 and Kv1.3 channels, expressed in Xenopus oocytes, with IC50 values of 0.26 and 180 nM, respectively. Moreover, MTX1 competitively interacts with both 125I-apamin (IC50 = 1.7 nM) and 125I-charybdotoxin (IC50 = 5 nM) for binding to rat brain synaptosomes. Despite its high sequence similarity (85%) to MTX, MTX1 exhibits a higher binding affinity towards the Kv1.2 and SKCa channels. Computational analysis highlights the significance of specific residues in the \u03b2-sheet region, particularly the R27, in enhancing the binding affinity of MTX1 towards the Kv1.2 and SKCa channels.<\/jats:p>","DOI":"10.3390\/ijms251910472","type":"journal-article","created":{"date-parts":[[2024,9,30]],"date-time":"2024-09-30T03:12:28Z","timestamp":1727665948000},"page":"10472","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Structure\u2013Function Relationship of a Novel MTX-like Peptide (MTX1) Isolated and Characterized from the Venom of the Scorpion Maurus palmatus"],"prefix":"10.3390","volume":"25","author":[{"given":"Rym","family":"ElFessi","sequence":"first","affiliation":[{"name":"Laboratory of Venoms and Therapeutic Biomolecules, Pasteur Institute of Tunis, University of Tunis El Manar, 13 Place Pasteur, BP74, Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3617-5705","authenticated-orcid":false,"given":"Oussema","family":"Khamessi","sequence":"additional","affiliation":[{"name":"Laboratory of Venoms and Therapeutic Biomolecules, Pasteur Institute of Tunis, University of Tunis El Manar, 13 Place Pasteur, BP74, Tunis 1002, Tunisia"},{"name":"Laboratory of Bioinformatics, Biomathematics and Biostatistics (LR20IPT09), Pasteur Institute of Tunis, University of Tunis El Manar, Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2782-9615","authenticated-orcid":false,"given":"Michel","family":"De Waard","sequence":"additional","affiliation":[{"name":"l\u2019Institut du Thorax, Nantes Universit\u00e9, Centre National de la Recherche Scientifique (CNRS), Institut National de la Sant\u00e9 Et de la Recherche M\u00e9dical (INSERM), F-44000 Nantes, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1296-0909","authenticated-orcid":false,"given":"Najet","family":"Srairi-Abid","sequence":"additional","affiliation":[{"name":"LR20IPT01 Biomol\u00e9cules, Venins et Applications Th\u00e9ranostiques, Institut Pasteur de Tunis, Universit\u00e9 de Tunis El Manar, Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3387-6493","authenticated-orcid":false,"given":"Kais","family":"Ghedira","sequence":"additional","affiliation":[{"name":"Laboratory of Bioinformatics, Biomathematics and Biostatistics (LR20IPT09), Pasteur Institute of Tunis, University of Tunis El Manar, Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2311-576X","authenticated-orcid":false,"given":"Riadh","family":"Marrouchi","sequence":"additional","affiliation":[{"name":"Laboratory of Venoms and Therapeutic Biomolecules, Pasteur Institute of Tunis, University of Tunis El Manar, 13 Place Pasteur, BP74, Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Riadh","family":"Kharrat","sequence":"additional","affiliation":[{"name":"Laboratory of Venoms and Therapeutic Biomolecules, Pasteur Institute of Tunis, University of Tunis El Manar, 13 Place Pasteur, BP74, Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,9,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"821","DOI":"10.1124\/pr.114.009654","article-title":"The Physiology, Pathology, and Pharmacology of Voltage-Gated Calcium Channels and Their Future Therapeutic Potential","volume":"67","author":"Zamponi","year":"2015","journal-title":"Pharmacol. 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