Atomic force microscopy observation of the condensates of the spermidine-DNA complexes  

作　　者：林璋 王琛 苏明 田芳 马金 白春礼 

出　　处：《Science China Chemistry》1998年第4期418-423,共6页中国科学（化学英文版）

基　　金：theNationalNaturalScienceFoundationofChina (GrantNo .2 95 2 5 30 4 )

摘　　要：In vitro investigation on the condensation of DNA induced by naturally occurring polyamines can provide useful insights into the packaging state of DNA in vivo , which is closely related to the mechanism of the self regulation or self switching of the gene expression. The present paper reports the high resolution AFM observations of the condensates of spermidine DNA complexes. It was found that the spermidine can directly condense the DNA into toroidal structures. The formation of this special structure is greatly influenced by the dynamic factors such as the concentrations and the reaction time. Close examination revealed that the toroids were constructed by many particles stacked and squeezed together. Our observations indicate that the dynamic process of the toroid formation may be a spiral wound process of the globular subunits.In vitro investigation on the condensation of DNA induced by naturally occurring polyamines can provide useful insights into the packaging state of DNAin vivo, which is closely related to the mechanism of the self-regulation or self-switching of the gene expression. The present paper reports the high resolution AFM observations of the condensates of spermidine-DNA complexes. It was found that the spermidine can directly condense the DNA into toroidal structures. The formation of this special structure is greatly influenced by the dynamic factors such as the concentrations and the reaction time. Close examination revealed that the toroids were constructed by many particles stacked and squeezed together. Our observations indicate that the dynamic process of the toroid formation may be a spiral wound process of the globular subunits.

关 键 词：TOROIDAL CONDENSATES SPERMIDINE AFM SPIRAL WOUND process of globular subunits. 

分 类 号：Q523[生物学—生物化学]