CAJ | 학술논문

用同步辐射小角和宽角X光衍射实验技术研究了由二棕榈酰磷脂酰胆碱(DPPC)和豆固醇所形成的脂质体的液态有序相的结构性质.结果表明液态有序相的小角X光衍射d值(d-spacing)随着固醇温度和浓度的变化仅有微小的改变.与凝胶相及液晶相的宽角X光衍射d值相比,液态有序相的宽角X光衍射d值有更宽的变化范围,在30-52 ℃的温度范围内,液态有序相的宽角X光衍射d值从0.422 nm变化到0.460 nm.电子云密度计算表明液态有序相的脂双层厚度和水层厚度都要大于与之平衡共存的液晶相的脂双层厚度和水层厚度.电子云密度计算结果还表明液态有序相的脂双层厚度随温度升高而降低.本研究结果对于从定量的角度认识生物膜的相态及深入认识生物膜中的有序结构具有重要意义.
용동보복사소각화관각X광연사실험기술연구료유이종려선린지선담감(DPPC)화두고순소형성적지질체적액태유서상적결구성질.결과표명액태유서상적소각X광연사d치(d-spacing)수착고순온도화농도적변화부유미소적개변.여응효상급액정상적관각X광연사d치상비,액태유서상적관각X광연사d치유경관적변화범위,재30-52 ℃적온도범위내,액태유서상적관각X광연사d치종0.422 nm변화도0.460 nm.전자운밀도계산표명액태유서상적지쌍층후도화수층후도도요대우여지평형공존적액정상적지쌍층후도화수층후도.전자운밀도계산결과환표명액태유서상적지쌍층후도수온도승고이강저.본연구결과대우종정량적각도인식생물막적상태급심입인식생물막중적유서결구구유중요의의.
The properties of the liquid ordered (L(.)) phase of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/stigmasterol liposomes were investigated using synchrotron small-angle and wide-angle X-ray diffraction techniques.The lamellar repeat distance of the L.phase,derived from small-angle X-ray scattering experiments,changes slightly with sterol concentration and tamperature.While the d-spacings of the acyl chains,evaluated from wide-angle X-ray scattering data,show a much broader range than those of the gel and liquid-crystal phases,varying from 0.422 to 0.460 nm when the temperature increases from 30 to 52 ℃.The electron density profiles show that the bilayer thickness and the water-layer thickness of the liquid-ordered phase are larger than that of the liquid-crystal phase,and the bilayer thickness of the liquid-ordered phase decreases with increasing temperature.The results of this study are of help in understanding the phase state and the ordered structure of biomembranes.