Structure-Function Elucidation of a New α-Conotoxin, Lo1a, from Conus longurionis
Structure-Function Elucidation of a New α-Conotoxin, Lo1a, from Conus longurionis
复制标题
DOI：
10.1074/jbc.m114.556175
复制
发表时间：
2014-04-04
影响因子：
4.8
通讯作者：
Tytgat, Jan
中科院分区：
文献类型：
--
作者：
Lebbe, Eline K. M.;Peigneur, Steve;Tytgat, Jan
背景：芋螺毒素是由锥螺产生的小毒素，是烟碱乙酰胆碱受体的拮抗剂。结果：获得了两个长尾芋螺毒素C末端的突变体.结论：我们的特点是一个重要的残基之间的神经元和肌肉亚型烟碱乙酰胆碱受体的歧视。意义：这为设计新的配体来影响大脑疾病开辟了前景。芋螺毒素是在海洋锥螺毒液中发现的肽毒素，并且是烟碱乙酰胆碱受体（nAChR）的各种亚型的有效拮抗剂。nAChR是在某些神经元和神经肌肉接头的质膜中形成配体门控离子通道的胆碱能受体。由于nAChR在调节递质释放、细胞兴奋性和神经元整合中具有重要作用，因此nAChR功能障碍与多种严重病理学有关，例如癫痫、肌无力综合征、精神分裂症、帕金森病和阿尔茨海默病。为了扩大有关锥螺毒素的知识，我们检查了芋螺的毒液。我们分离出一个18个氨基酸的肽名为芋螺毒素Lo 1a，这是积极的nAChRs。据我们所知，这是第一次表征芋螺毒素从这个物种。该肽的特点是对几种类型的克隆nAChRs在非洲爪蟾卵母细胞中表达的电生理筛选。的三维溶液结构的芋螺毒素Lo 1a的NMR光谱测定。Lo 1a是4/7家族的成员，可阻断表达（7）nAChR的卵母细胞对乙酰胆碱的反应，IC 50为3.24 +/- 0.7 m。此外，Lo 1a显示出对神经元与肌肉亚型nAChR的高选择性。由于Lo 1a有一个不寻常的C端，我们设计了两个突变体，Lo 1a-D和Lo 1a-RRR，以研究C端残基的影响。Lo 1a-D具有C-末端Asp缺失，而在Lo 1a-RRR中，三重Arg尾取代了Asp。它们以较低的IC 50值阻断神经元nAChR（7），但值得注意的是，两者都采用了对肌肉亚型E-11的亲和力。
Background: -Conotoxins are small toxins produced by cone snails and antagonists of nicotinic acetylcholine receptors. Results: Two mutants were created to investigate the unusual C terminus of a novel -conotoxin from Conus longurionis. Conclusion: We characterized an important residue for discrimination between neuronal and muscle subtype nicotinic acetylcholine receptors. Significance: This opens perspectives for designing new ligands to affect brain disorders.-Conotoxins are peptide toxins found in the venom of marine cone snails and potent antagonists of various subtypes of nicotinic acetylcholine receptors (nAChRs). nAChRs are cholinergic receptors forming ligand-gated ion channels in the plasma membranes of certain neurons and the neuromuscular junction. Because nAChRs have an important role in regulating transmitter release, cell excitability, and neuronal integration, nAChR dysfunctions have been implicated in a variety of severe pathologies such as epilepsy, myasthenic syndromes, schizophrenia, Parkinson disease, and Alzheimer disease. To expand the knowledge concerning cone snail toxins, we examined the venom of Conus longurionis. We isolated an 18-amino acid peptide named -conotoxin Lo1a, which is active on nAChRs. To the best of our knowledge, this is the first characterization of a conotoxin from this species. The peptide was characterized by electrophysiological screening against several types of cloned nAChRs expressed in Xenopus laevis oocytes. The three-dimensional solution structure of the -conotoxin Lo1a was determined by NMR spectroscopy. Lo1a, a member of the 4/7 family, blocks the response to acetylcholine in oocytes expressing (7) nAChRs with an IC50 of 3.24 +/- 0.7 m. Furthermore, Lo1a shows a high selectivity for neuronal versus muscle subtype nAChRs. Because Lo1a has an unusual C terminus, we designed two mutants, Lo1a-D and Lo1a-RRR, to investigate the influence of the C-terminal residue. Lo1a-D has a C-terminal Asp deletion, whereas in Lo1a-RRR, a triple-Arg tail replaces the Asp. They blocked the neuronal nAChR (7) with a lower IC50 value, but remarkably, both adopted affinity for the muscle subtype E-11.