Era S, Nagaoka S, Sogami M, Watari H, Akasaka K
Int J Pept Protein Res. 1985 Jul;26(1):21-32.
The acid-induced isomerization (the N-F transition) and expansion of sodium dodecyl sulfate-bovine plasma albumin complex (ADm; m, molar ratio of added sodium dodecyl sulfate to bovine plasma albumin; O less than or equal to m less than or equal to 12) were studied by measuring CD-resolved secondary structure, fluorescence polarization and life-time of tryptophyl fluorophors, acid-titration with the electrostatic correction for the surface potential, 1H-n.m.r. spectra and cross relaxation time between irradiated and observed protons. The immobilization of tryptophyl fluorophors observed in the F-form of AD0 was suppressed in the F-form of AD10. The acidtitration analysis of AD12 showed non salt-bonding between carboxylate groups and cationic side chains in the F-form, as in the case of AD0, indicating charged side chains being presumably mobile. 1H-n.m.r. spectra and cross relaxation times between irradiated and observed protons in the F-form of AD10 indicated the increase in the local motion. On the other hand, AD10 and AD12 did not show any significant change in the CD-resolved secondary structure in the N-F transition region. The F-form of AD10 or AD12 may therefore be the moltenglobule state which has secondary structure similar to the N-form of the complexes with fluctuating tertiary structure (side chains).
通过测量圆二色光谱解析的二级结构、荧光偏振和色氨酸荧光团的寿命、考虑表面电势静电校正的酸滴定、1H-核磁共振光谱以及照射质子与观测质子之间的交叉弛豫时间，研究了酸诱导的十二烷基硫酸钠-牛血浆白蛋白复合物（ADm；m为添加的十二烷基硫酸钠与牛血浆白蛋白的摩尔比；0≤m≤12）的异构化（N-F转变）和膨胀。在AD0的F型中观察到的色氨酸荧光团的固定化在AD10的F型中受到抑制。AD12的酸滴定分析表明，与AD0的情况一样，F型中羧基与阳离子侧链之间不存在盐键，这表明带电侧链可能是可移动的。AD10的F型中的1H-核磁共振光谱以及照射质子与观测质子之间的交叉弛豫时间表明局部运动增加。另一方面，AD10和AD12在N-F转变区域的圆二色光谱解析的二级结构中未显示任何显著变化。因此，AD10或AD12的F型可能是熔球态，其二级结构与具有波动三级结构（侧链）的复合物的N型相似。
