POLYAMINE - POLYNUCLEOTIDE INTERACTIONS

这项研究的总体目标是确定 多胺对结构和动力学的影响，因此对 DNA的相互作用。 多胺水平显著升高， 增殖细胞和许多肿瘤，重要的是要建立坚定的 这些观察结果和分子机制之间的联系。 我们 研究将着重三个方面。 (1)亚精胺和精胺有一些 对DNA二级和三级结构的巨大影响，在B-Z 过渡和冷凝。 我们希望确定是否更微妙， 但也许同样重要的是，局部扭曲和变形效应可能 出现，通过测量超螺旋DNA的流体力学在 多胺的存在。 (2)多胺，像其他阳离子，提高 DNA的解链温度，可能是通过以下因素的结合 静电和特异性结合效应。 这意味着对 DNA的碱基配对和堆积动力学，这可能会影响其 与酶和配体的相互作用。 我们希望调查这些 质子交换和三重态各向异性衰减的动态效应， DNA扭曲和弯曲的流体动力学测量。 (3)多胺 影响复制转录和翻译 这意味着他们 影响蛋白质与核酸的结合。 我们想测试一下 通过体外测量多胺对 小麦胚芽RNA聚合酶II与DNA的结合。 将特别注意 对启动子位点特异性结合的不同影响 与非特异性结合相比。

The overall goal of this research is to determine the effects that polyamines have on the structure and dynamics, and thus on the interactions, of DNA. Polyamine levels are markedly elevated in rapidly proliferating cells and many tumors, and it is important to establish firm connections between these observations and molecular mechanisms. Our studies will emphasize three areas. (1) Spermidine and spermine have some dramatic effects on DNA secondary and tertiary structure, in the B-Z transition and in condensation. We wish to determine whether more subtle, but perhaps equally important, local twisting and deformation effects may arise, through measurements of the hydrodynamics of supercoiled DNA in the presence of polyamines. (2) Polyamines, like other cations, raise the melting temperature of DNA, presumably through a combination of electrostatic and specific binding effects. This implies an effect on the base pairing and stacking dynamics of DNA, which may affect its interactions with enzymes and ligands. We wish to investigate these dynamic effects by proton exchange and by triplet anisotropy decay and hydrodynamic measurements of DNA twisting and bending. (3) Polyamines affect replication, transcription, and translation. This implies that they influence the binding of proteins to nucleic acids. We wish to test this hypothesis by in vitro measurements of the effects of polyamines on the binding of wheat germ RNA polymerase II to DNA. Particular attention will be paid to differential effects on specific binding to promoter sites compared to nonspecific binding.