SEQUENCE-SPECIFIC RECOGNITION OF DNA BY DIMER MOTIFS

说明(申请人提供)：为一个已资助三年以上的项目申请延续资金，该项目支持在核酸靶向药物设计和合成以及核酸复合体的生物物理化学方面的合作实验室。根据在初始资助下获得的结果，杂环阳离子的堆积二聚体显然代表了一个强大的新基序，用于特定的、强烈的识别混合碱基对DNA序列和抑制蛋白质-DNA复合体。这些化合物毒性低，具有良好的生物活性，这类化合物将进入第三阶段临床试验。由于双螺旋的两条链包含不同的化学信息，因此识别DNA的化合物如果同时读取两条链，就可以以最高的特异性识别DNA。基于这些观察，我们的假设是，设计的杂环阳离子对DNA的堆积二聚体识别提供了独特的机会，为开发新的药物类别提供了广泛的选择性分子识别双链和抑制DNA-蛋白质复合物的机会。这类二聚体具有作为新型治疗药物、生物技术试剂、控制细胞基因表达的试剂和抑制特定蛋白质-DNA复合体的巨大潜力。我们已经设计并正在研究两个二聚体堆积基序，它们以新的和不同的方式识别次要凹槽。一个系统正在开发中，以抑制bZlP转录因子，如Fos/Jun癌蛋白，而第二个系统将靶向次要沟槽HMGA癌蛋白。我们将制备和研究这样的化合物：(I)通过使用各种杂环来提高二聚体系统的序列识别能力；(Ii)通过延长二聚体的长度来延长所读取的碱基序列的长度；(Iii)通过制备共价二聚体来增强结合的亲和力和特异性。化合物-DNA复合体将用一系列强大的生物物理方法进行表征，包括核磁共振和X射线；酶和化学足迹；生物传感器-SPR和ITC。在最基本的水平上，杂环二聚体系统将为DNA识别的分子基础以及碱基对化学、溶剂和配体性质的局部相互作用如何影响提供重要的新理解。杂环系统是唯一靶向DNA与临床有用的细胞渗透剂的混合序列的基序。

DESCRIPTION (provided by applicant): Continuation funds are requested for a project that has been funded for three+ years and that supports collaborating laboratories in nucleic acid targeted drug design and synthesis and in the biophysical chemistry of nucleic acid complexes. Based on results obtained under initial funding, it is clear that stacked-dimers of heterocyclic cations represent a powerful new motif for specific, strong recognition of mixed base pair DNA sequences and inhibition of protein-DNA complexes. The compounds have low toxicity with excellent biological activity and a compound from this class is set to enter Phase III clinical trials. Since the two strands of the double helix contain different chemical information, compounds that recognize DNA can do so with the highest specificity if they read both strands. Based on these observations our hypothesis is that stacked dimer recognition of DNA by designed heterocyclic cations offers unique opportunities for development of new classes of drugs for broad-based selective molecular recognition of the duplex and inhibition of DNA-protein complexes. Such dimers have significant potential for development as new types of therapeutics, for reagents in biotechnology, as agents for control of cellular gene expression, and for inhibition of specific protein-DNA complexes. We have designed and are studying two dimer-stacking motifs that recognize the minor groove in new and different ways. One system is being developed to inhibit bZlP transcription factors such as the Fos/Jun oncoproteins, while the second system will target the minor groove HMGA oncoproteins. We will prepare and study compounds that (i) increase the sequence recognition capability of the dimer systems by using a variety of heterocycles; (ii) extend the length of the base sequence that is read by extending the length of the dimers; (iii) enhance the affinity and specificity of binding by preparation of covalent dimers. The compound-DNA complexes will be characterized with a powerful array of biophysical methods including NMR and x-ray; enzymatic and chemical footprinting; biosensor-SPR and ITC. At the most fundamental level, the heterocyclic dimer systems will provide significant new understanding of the molecular basis of DNA recognition and how it is affected by the local interplay of base pair chemistry, solvent and ligand properties. The heterocyclic system is the only motif for targeting mixed sequences of DNA with clinically useful and cell permeable agents.