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利用冷冻电子显微镜三维重构技术获得了分辨率为7.8?的乙型肝炎核心抗原于C端154aa处截短颗粒(HBcAg-154)的三维结构.结构显示,该颗粒主要由α螺旋组成,蛋白质折叠与核心抗原C端149截短颗粒(HBcAg-149)极其相似.而且二者内部均很难观察到RNA的电子密度,近乎是空的.导致该结果的原因可能是由于150~154aa的短肽仅含5个氨基酸,序列太短以致不能结合足够的RNA分子,可见核心蛋白C端的155~183aa区域对于颗粒的核酸包裹更为重要.
The three-dimensional structure of truncated HBcAg-154 at the C-terminal of 154aa was obtained by cryogenic electron microscopy (3D-DWT) with a resolution of 7.8 μm. The structure of the particle was mainly composed of α-helix. The protein The folding is very similar to the truncated particle of core antigen C-terminal 149 (HBcAg-149), and the electron density of RNA is hard to be observed inside both, almost empty. The reason for this may be due to the short The peptide contains only 5 amino acids and the sequence is so short that it can not bind enough RNA molecules. Thus, the 155-183aa region at the C-terminus of the core protein is more important for nucleic acid encapsulation of the particles.