多种方法研究6-吡咯脱氧胞苷的发夹结构  

Study of the Hairpin Structure of 6PdC via Multiple Methods

作　　者：孙凌志[1] 张旭[1] 

机构地区：[1]盐城师范学院药学院,江苏盐城224051

出　　处：《重庆师范大学学报（自然科学版）》2016年第6期120-126,共7页Journal of Chongqing Normal University:Natural Science

基　　金：江苏省六大人才高峰资助项目(No.swyy-030);江苏省盐土生物资源研究重点实验室开放课题(No.JKLBS2012024)

摘　　要：为更好地了解DNA发卡结构在生物学上的功能,利用时间分辨荧光光谱和2D-NOE NMR谱确定6-吡咯脱氧胞苷(6PdC)的二级结构,用滴定曲线测定7-氨基放线菌素D(7AAMD)滴定DNA的Kd值,并用Z-DOCK方法计算7AAMD与DNA的绑定位置。结果显示,6PdC的表观时间分辨寿命为1.44ns,而7-吡咯脱氧胞苷(7PdC)的该寿命为2.81ns;在2D-NOE NMR谱中处于H8/H6区域的交叉峰,除了处于7,8,9,10位上的脱氧胞苷(dC)的NOE很弱甚至难以观察到外,其他的dC的NOE交叉峰很强,并且可以很好地归属;滴定曲线显示AACC4,7PdC,6PdC,AACC4-comp等与7AAMD的Kd值分别是0.1,0.31,0.46,0.57;Z-DOCK计算结果显示7AAMD的平面多环插入发夹环。研究结果说明DNA的结构决定7AAMD与自身亲和力的强弱,而吡咯脱氧胞苷(PdC)的空间位阻的影响有限;揭示7AAMD可能通过与启动子或增强子的发夹部位结合抑制或减弱原癌基因的转录水平,达到抗癌作用。To better understand the biological function of DNA hairpin,determining the secondary structure of 6-pyrolo deoxycytidine（6PdC）using the time-resolved fluorescence,2D-NOE NMR spectra,titration curves and as well as Z-DOCK computational method were conducted.The time-resolved fluorescence apparent lifetime of 7-pyrolo deoxycytidine（7PdC）is 2.81 ns and 6PdC is1.44ns;2D-NOE NMR spectra shown that the backbone of 6PdC can be well assigned via cross-peaks in the H8/H6 region,however,the intensity of NOEs of dCs at position 7,8,9,10 are very weak and are hardly to be assigned;the titration results indicated that the Kdvalues of AACC4 is 0.1,7PdC is 0.31,6PdC is 0.46 and AACC4-comp is 0.57;the results of Z-DOCK computing indicated that the planar polycyclic ring of 7-aminoactinomycin D is inserted into the loop of the hairpin.The above results suggested that the DNA structure plays a key role in binding affinity,and the steric hindrance has certain effect,but not the important one;the 7AAMD may be bound to promoter or enhancer,which is hairpin,to inhibit or suppress the transcription of oncogenes,thus far achieving the anti-cancer effect.

关 键 词：发夹结构 时间分辨荧光光谱 2D-NOE核磁共振 7-氨基放线菌素D 分子动力学模拟计算 6-吡咯脱氧胞苷 

分 类 号：Q63[生物学—生物物理学]