Satoh O, Imai H, Yoneyama T, Miyamura T, Utsumi H, Inoue K, Umeda M
Tokyo R&D Center, Daiichi Pharmaceutical Co. Ltd., Kitakasai, Edogawa-ku, Tokyo 134-8630, Japan.
J Biochem. 2000 Apr;127(4):543-50. doi: 10.1093/oxfordjournals.jbchem.a022639.
Expression of S protein, an envelope protein of hepatitis B virus, in the absence of other viral proteins, leads to the secretion of hepatitis B virus surface antigen (HBsAg) particles that are formed by budding from the endoplasmic reticulum membranes. The HBsAg particles produced by mouse fibroblast cells show a unique lipid composition, with 1,2-diacyl glycerophosphocholine being the dominant component. The lipid organization of the HBsAg particles was studied by measuring electron spin resonance (ESR) using various spin-labeled fatty acids, and the results were compared with a parallel study on HVJ (Sendai virus) and vesicles reconstituted with total lipids of the HBsAg particles (HBs-lipid vesicles). HVJ and the HBs-lipid vesicles showed typical ESR spectra of lipids arranged in a lipid bilayer structure. In contrast, the ESR spectra obtained with the HBsAg particles showed that the movement of lipids in the particle is severely restricted and a typical immobilized signal characteristic of tight lipid-protein interactions was also evident. Phosphatidylcholine (PC) in the HBsAg particles was not exchangeable by a PC-specific exchange protein purified from bovine liver, while phospholipase A(2) from Naja naja vemon was able to hydrolyze all the PC in the particles. These analyses suggest that the lipids in the HBsAg particles are not organized in a typical lipid bilayer structure, but are located at the surface of the particles and are in a highly immobilized state. Based on these observations we propose a unique lipid assembly and membrane structure model for HBsAg particles.
乙型肝炎病毒包膜蛋白S蛋白在无其他病毒蛋白的情况下表达,会导致乙型肝炎病毒表面抗原(HBsAg)颗粒从内质网膜出芽分泌。小鼠成纤维细胞产生的HBsAg颗粒具有独特的脂质组成,其中1,2 - 二酰基甘油磷酸胆碱是主要成分。通过使用各种自旋标记脂肪酸测量电子自旋共振(ESR)来研究HBsAg颗粒的脂质组织,并将结果与对HVJ(仙台病毒)和用HBsAg颗粒总脂质重构的囊泡的平行研究进行比较。HVJ和HBs - 脂质囊泡显示出脂质双层结构中脂质的典型ESR光谱。相比之下,用HBsAg颗粒获得的ESR光谱表明,颗粒中脂质的运动受到严重限制,脂质 - 蛋白质紧密相互作用的典型固定信号也很明显。HBsAg颗粒中的磷脂酰胆碱(PC)不能被从牛肝中纯化的PC特异性交换蛋白交换,而眼镜蛇毒中的磷脂酶A(2)能够水解颗粒中的所有PC。这些分析表明,HBsAg颗粒中的脂质不是以典型的脂质双层结构组织的,而是位于颗粒表面并处于高度固定状态。基于这些观察结果,我们提出了一种独特的HBsAg颗粒脂质组装和膜结构模型。