Open conformation of hERG channel turrets revealed by a specific scorpion toxin BmKKx2
| Autor: | Jing Jing Wei, Yi Mei Du, Tian Li, Ying Liang Wu, Wenxin Li, Jun Hu, You Tian Hu, Jing Feng, Zhi Jian Cao |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
congenital
hereditary and neonatal diseases and abnormalities Mesobuthus martensii Mutant hERG Pharmacology medicine.disease_cause Turret General Biochemistry Genetics and Molecular Biology Molecular mechanism BmKKx2 medicine cardiovascular diseases Alanine Scorpion toxin biology Chemistry Toxin Research Mutagenesis hERG channel biology.organism_classification Potassium channel Biophysics biology.protein Pore region |
| Zdroj: | Cell & Bioscience |
| ISSN: | 2045-3701 |
| Popis: | Background The human ether-a-go-go-related gene potassium channel (hERG) has an unusual long turret, whose role in recognizing scorpion toxins remains controversial. Here, BmKKx2, the first specific blocker of hERG channel derived from scorpion Mesobuthus martensii, was identified and the turret role of hERG channel was re-investigated using BmKKx2 as a molecular probe. Results BmKKx2 was found to block hERG channel with an IC50 of 6.7 ± 1.7 nM and share similar functional surface with the known hERG channel inhibitor BeKm-1. The alanine-scanning mutagenesis data indicate that different residue substitutions on hERG channel by alanine decreased the affinities of toxin BmKKx2 by about 10-fold compared with that of wild-type hERG channel, which reveals that channel turrets play a secondary role in toxin binding. Different from channel turret, the pore region of hERG channel was found to exert the conserved and essential function for toxin binding because the mutant hERG-S631A channel remarkably decreased toxin BmKKx2 affinity by about 104-fold. Conclusions Our results not only revealed that channel turrets of hERG channel formed an open conformation in scorpion toxin binding, but also enriched the diversity of structure-function relationships among the different potassium channel turrets. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink