Norton R S, Beress L, Stob S, Boelens R, Kaptein R
Eur J Biochem. 1986 Jun 2;157(2):343-6. doi: 10.1111/j.1432-1033.1986.tb09674.x.
One-dimensional and two-dimensional photochemically induced dynamic nuclear polarisation (photo-CIDNP) nuclear magnetic resonance spectra have been recorded for the sea-anemone polypeptide cardiac stimulants anthopleurin-A and Anemonia sulcata toxins I and II. In anthopleurin-A and toxin II, all three Trp residues are accessible to the flavin dye, although Trp-23 in anthopleurin-A shows a weaker photo-CIDNP response than Trp-33 and Trp-45. Tyr-25 in anthopleurin-A also shows a strong response. In toxin I, Trp-23, Trp-33 and Tyr-45 (which replaces Trp in this molecule) are accessible to the dye. The pH dependences of the photo-CIDNP spectra of all three polypeptides have been examined. The response of Trp-33 increases significantly with pH. The two His residues of anthopleurin-A and toxin II display a response in their imidazole forms, but not their imidazolium forms. The surface accessibilities of Trp-23 and Trp-33 are discussed in relation to the interaction of these polypeptides with the Na+ channel.
已记录了海葵多肽类心脏兴奋剂海葵毒素A以及沟迎风海葵毒素I和II的一维及二维光化学诱导动态核极化（光CIDNP）核磁共振谱。在海葵毒素A和毒素II中，所有三个色氨酸残基均可与黄素染料接触，尽管海葵毒素A中的色氨酸-23比色氨酸-33和色氨酸-45表现出较弱的光CIDNP响应。海葵毒素A中的酪氨酸-25也表现出强烈响应。在毒素I中，色氨酸-23、色氨酸-33和酪氨酸-45（该分子中取代色氨酸的氨基酸）均可与染料接触。已研究了所有三种多肽的光CIDNP谱的pH依赖性。色氨酸-33的响应随pH显著增加。海葵毒素A和毒素II的两个组氨酸残基以咪唑形式而非咪唑鎓形式表现出响应。结合这些多肽与钠离子通道的相互作用，讨论了色氨酸-23和色氨酸-33的表面可及性。
