{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T22:28:09Z","timestamp":1791325689581,"version":"4.3.1"},"reference-count":31,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2014,4,22]],"date-time":"2014-04-22T00:00:00Z","timestamp":1398124800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Toxins"],"abstract":"<jats:p>Martentoxin (MarTX), a 37-residue peptide purified from the venom of  East-Asian scorpion (Buthus martensi Karsch), was capable of blocking large-conductance Ca2+-activated K+ (BK) channels. Here, we report an effective expression and purification approach for this toxin. The cDNA encoding martentoxin was expressed by the prokaryotic expression system pGEX-4T-3 which was added an enterokinase cleavage site by PCR. The fusion protein (GST-rMarTX) was digested by enterokinase to release hetero-expressed toxin and further purified via reverse-phase HPLC. The molecular weight of the hetero-expressed rMarTX was 4059.06 Da, which is identical to that of the natural peptide isolated from scorpion venom. Functional characterization through whole-cell patch clamp showed that rMarTX selectively and potently inhibited the currents of neuronal BK channels (\u03b1 + \u03b24) (IC50 = 186 nM), partly inhibited mKv1.3, but hardly having any significant effect on hKv4.2 and hKv3.1a even at 10 \u03bcM. Successful expression of martentoxin lays basis for further studies of structure-function relationship underlying martentoxin or other potassium-channel specific blockers.<\/jats:p>","DOI":"10.3390\/toxins6041419","type":"journal-article","created":{"date-parts":[[2014,4,22]],"date-time":"2014-04-22T12:18:37Z","timestamp":1398169117000},"page":"1419-1433","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Recombinant Expression and Functional Characterization of Martentoxin: A Selective Inhibitor for BK Channel (\u03b1 + \u03b24)"],"prefix":"10.3390","volume":"6","author":[{"given":"Jie","family":"Tao","sequence":"first","affiliation":[{"name":"Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333,  Shanghai 200444, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhi","family":"Zhou","sequence":"additional","affiliation":[{"name":"Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333,  Shanghai 200444, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bin","family":"Wu","sequence":"additional","affiliation":[{"name":"Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333,  Shanghai 200444, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jian","family":"Shi","sequence":"additional","affiliation":[{"name":"Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333,  Shanghai 200444, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiao","family":"Chen","sequence":"additional","affiliation":[{"name":"Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333,  Shanghai 200444, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yong","family":"Ji","sequence":"additional","affiliation":[{"name":"Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333,  Shanghai 200444, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2014,4,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1111\/j.1469-7793.2001.00443.x","article-title":"Beta1-subunit of the Ca2+-activated K+ channel regulates contractile activity of mouse urinary bladder smooth muscle","volume":"537","author":"Petkov","year":"2001","journal-title":"J. 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