Maget-Dana R, Bonmatin J M, Hetru C, Ptak M, Maurizot J C
Centre de Biophysique Moléculaire (CNRS), Université d'Orléans, France.
Biochimie. 1995;77(4):240-4. doi: 10.1016/0300-9084(96)88130-2.
Defensin A is an inducible antibacterial protein isolated from the larvae of Phormia terranovae. The conformation of defensin A has been previously determined by two-dimensional 1H-NMR for concentrations in the range of 4-8 mM in water (Bonmatin JM et al (1992) J Biomol NMR 2, 235-256). CD spectroscopic data of defensin A at lower concentrations (10(-5) to 10(-3) M) are reported herein. The ellipticity in the 200-240 nm wavelength range for various solvents varies as follows: acetonitrile < water < methanol < HFIP. The magnitude of theta 222 is strongly dependent on defensin concentration in a buffer solution, suggesting an aggregation process. The helical content of defensin A is maximum at a pH value range (7.5-8) for which the optimum antibacterial activity was observed (Cociancich S et al (1993) J Biol Chem 268, 19239-19245).
防御素A是一种从新陆原伏蝇幼虫中分离出的可诱导抗菌蛋白。防御素A的构象先前已通过二维1H-NMR确定，其在水中的浓度范围为4-8 mM（博马坦 JM等人，(1992)《生物分子核磁共振杂志》2, 235-256）。本文报道了较低浓度（10^(-5)至10^(-3) M）下防御素A的圆二色光谱数据。不同溶剂在200-240 nm波长范围内的椭圆率变化如下：乙腈<水<甲醇<六氟异丙醇。θ222的大小强烈依赖于缓冲溶液中防御素的浓度，表明存在聚集过程。防御素A的螺旋含量在观察到最佳抗菌活性的pH值范围（7.5-8）时最高（科西安奇奇S等人，(1993)《生物化学杂志》268, 19239-19245）。
