摘要
ＳｔｕｄｉｅｓｏｎｓｔｒｕｃｔｕｒａｌｆｅａｔｕｒｅｓｏｆｈｕｍａｎｔｕｍｏｒｎｅｃｒｏｓｉｓｆａｃｔｏｒＴｈｅＰｒｏｊｅｃｔＳｕｐｐｏｒｔｅｄｂｙＮａｔｉｏｎａｌＮａｔｕｒａｌＳｃｉｅｎｃｅＦｏｕｎｄａｔｉｏｎｏｆＣｈｉｎａＭａｎｕｓｃｒｉｐｔ...
The microstructure of human tumor necrosis factor alpha (TNF α) and its mutant (TNF b) has been investigated by utilizing positron annihilation lifetime spectroscopy, radioiodination of human TNF and L929 cells assay. The experimental results show that the long lifetime ( τ 2 ) and corresponding intensity ( I 2 ) of lower ortho positronium annihilation in TNF α are longer and less than those in the TNF b, respectively. It suggests that the TNF b is smaller in free volume and higher in density than the TNF α. The TNF b may maintain a more favorable conformation for binding to TNF receptors, thus increasing its biological activity. It is then concluded that the increases in the cytotoxicity and in the density for the TNF b result from the decreases in the free volume in the TNF b.
关键词
人体肿瘤坏死因子
结构特征
质子湮没技术
Positron annihilation technique (PAT),Receptor binding assay, Tumor necrosis factor (TNF), Cytotoxicity
