Important amino acid residues for the crab toxicity of PaTX, a type 3 sodium channel peptide toxin from the sea anemone Entacmaea actinostoloides
Important amino acid residues for the crab toxicity of PaTX, a type 3 sodium channel peptide toxin from the sea anemone Entacmaea actinostoloides
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PaTX 是一种对蟹具有毒性的重要氨基酸残基，PaTX 是一种来自海葵 Entacmaea actinostoloides 的 3 型钠通道肽毒素
DOI：
10.1007/s12562-014-0830-y
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发表时间：
2015
影响因子：
1.9
通讯作者：
河野晃徳・本間智寛・塩見一雄
中科院分区：
文献类型：
--
作者：
Asami Yoshida;Yajun Wang;Inwoo Bae;Min-Jie Cao;Kiyoshi Osatomi;Kenji Hara.;河野晃徳・本間智寛・塩見一雄
海葵体内的钠通道毒素一般可分为三类。3型毒素(27-32个残基)在链长上不同于1型和2型毒素(46-49个残基)。在已知的3型毒素(ATX III、Da I、Da II、PaTX和Er I)中，ATX III的构效关系已被阐明。然而，ATX III获得的数据似乎并不适用于3型毒素，因为ATX III在构象和一级结构上与其他3型毒素显著不同。因此，本研究的目的是确定对PaTX的毒性起重要作用的氨基酸残基。首先，利用化学合成的Er-I，确定了最佳的复性条件；然后，用反相高效液相色谱(HPLC)合成、复性和纯化了PaTX(一种长度比Er-I短1个残基的多肽)及其类似物，每个多肽都带有丙氨酸取代基。对纯化制剂的蟹毒性测定表明，两个阳离子残基(Lys-4和His-27)和三个疏水残基(Tyr-15、Pro-20和Trp-21)与PaTX的毒性密切相关。PaTX的结果基本上适用于大I、大II和Er I。
Sodium channel toxins from various sea anemones can generally be classified into three types. Type 3 toxins (27–32 residues) are distinct from type 1 and 2 toxins (46–49 residues) in chain length. Of the known type 3 toxins (ATX III, Da I, Da II, PaTX, and Er I), ATX III has been clarified for structure–activity relationships. However, the data obtained with ATX III do not seem to be universal for type 3 toxins, since ATX III is significantly different in conformation as well as primary structure from the other type 3 toxins. Thus the aim of this study was to identify the amino acid residues that are important for the toxicity of PaTX. First, an optimal refolding condition was established using chemically synthesized Er I. Then, PaTX (a peptide one residue shorter in length than Er I) and its analogs, each of which has an Ala substitution, were synthesized, refolded, and purified using reverse-phase high-performance liquid chromatography (HPLC). The crab toxicities determined for the purified preparations showed two cationic residues (Lys-4 and His-27) and three hydrophobic residues (Tyr-15, Pro-20, and Trp-21) that were strongly implicated in the toxicity of PaTX. The results with PaTX are substantially applicable to Da I, Da II, and Er I.