Schneider A S, Herz R, Sonenberg M
Biochemistry. 1983 Mar 29;22(7):1680-6. doi: 10.1021/bi00276a025.
The fluorescence emission and circular dichroism spectra of chlortetracycline (CTC) have been measured, including the effects of multivalent cations (Ca, Mg, La), of medium polarity, and of interaction with human red cell membranes, lipids, and a variety of proteins. An obligatory role of Ca in the association of CTC with membranes was demonstrated. Binding and kinetic constants for the CTC-Ca chelate interaction with membranes and phospholipids were determined. The results suggest that the CTC-Ca chelate fluorescence is greatly enhanced in the vicinity of membrane phospholipid head groups. The circular dichroism spectra indicate a number of distinct CTC conformations corresponding to chelation of specific cations, to interaction with membranes and phospholipids, and to medium polarity. The high quantum yield CTC-Ca conformation associated with membranes or phospholipids was identified by its characteristic circular dichroism spectrum and is different from the CTC-Ca conformation in nonpolar media (80% methanol).
已测量了金霉素（CTC）的荧光发射光谱和圆二色光谱，包括多价阳离子（钙、镁、镧）、介质极性以及与人类红细胞膜、脂质和多种蛋白质相互作用的影响。证明了钙在CTC与膜结合中的必要作用。测定了CTC-钙螯合物与膜和磷脂相互作用的结合常数和动力学常数。结果表明，在膜磷脂头部基团附近，CTC-钙螯合物的荧光大大增强。圆二色光谱表明，对应于特定阳离子的螯合、与膜和磷脂的相互作用以及介质极性，存在许多不同的CTC构象。与膜或磷脂相关的高量子产率CTC-钙构象通过其特征性圆二色光谱得以鉴定，且不同于非极性介质（80%甲醇）中的CTC-钙构象。
