Zetta L, Kaptein R
Eur J Biochem. 1984 Nov 15;145(1):181-6. doi: 10.1111/j.1432-1033.1984.tb08538.x.
1H-NMR spectra at 600 MHz and 270 MHz and photo-chemically induced dynamic nuclear polarization (photo-CIDNP) spectra at 360 MHz of beta-endorphin in the presence of sodium dodecyl sulfate (SDS) micelles are reported and discussed in terms of structural changes and immobilization upon binding. On addition of micelles several NH protons show slow H-D exchange rate in 2H2O at p2H 4.6, 25 degrees C, which indicates that some regions of the polypeptide are buried and shielded from the direct interaction with the solvent. Moreover, in the methyl region of the spectrum strong changes are detected both in chemical shifts and line-widths, suggesting an appreciable interaction between the hydrophobic residues of beta-endorphin and the detergent micelles. All aromatic residues are strongly affected by the presence of SDS, supporting the notion that beta-endorphin can interact with both the hydrophobic and hydrophilic portion of the micelles. At physiological pH photo-CIDNP experiments indicate that SDS has about the same immobilizing effect on Tyr-1 and Tyr-27 as n-dodecylphosphorylcholine.
报告了在十二烷基硫酸钠（SDS）胶束存在下，β-内啡肽在600 MHz和270 MHz的1H-NMR光谱以及在360 MHz的光化学诱导动态核极化（photo-CIDNP）光谱，并根据结合时的结构变化和固定化情况进行了讨论。加入胶束后，在p2H 4.6、25℃的2H2O中，几个NH质子显示出缓慢的H-D交换速率，这表明多肽的某些区域被掩埋并免受与溶剂的直接相互作用。此外，在光谱的甲基区域，化学位移和线宽都检测到强烈变化，这表明β-内啡肽的疏水残基与去污剂胶束之间存在明显的相互作用。所有芳香族残基都受到SDS存在的强烈影响，支持了β-内啡肽可以与胶束的疏水和亲水部分相互作用的观点。在生理pH下，photo-CIDNP实验表明，SDS对Tyr-1和Tyr-27的固定作用与正十二烷基磷酰胆碱大致相同。
