PDF(Pubmed)
Abstract：
DNA Topoisomerase IIα (Top2A) is a nuclear enzyme that is a cancer drug target, and there is interest in identifying novel sites on the enzyme to inhibit cancer cells more selectively and to reduce off-target toxicity. The C-terminal domain (CTD) is one potential target, but it is an intrinsically disordered domain, which prevents structural analysis. Therefore, we set out to analyze the sequence of Top2A from 105 species using bioinformatic analysis, including the PSICalc algorithm, Shannon entropy analysis, and other approaches. Our results demonstrate that large (10th-order) interdependent clusters are found including non-proximal positions across the major domains of Top2A. Further, CTD-specific clusters of the third, fourth, and fifth order, including positions that had been previously analyzed via mutation and biochemical assays, were identified. Some of these clusters coincided with positions that, when mutated, either increased or decreased relaxation activity. Finally, sites of low Shannon entropy (i.e., low variation in amino acids at a given site) were identified and mapped as key positions in the CTD. Included in the low-entropy sites are phosphorylation sites and charged positions. Together, these results help to build a clearer picture of the critical positions in the CTD and provide potential sites/regions for further analysis.
摘要：
DNA拓扑异构酶IIα（Top2A）是一种核酶，是癌症药物的靶标，并且有兴趣鉴定酶上的新位点以更有选择性地抑制癌细胞并减少脱靶毒性。C端结构域（CTD）是一个潜在的目标，但这是一个内在无序的领域，这阻碍了结构分析。因此,我们开始使用生物信息学分析来分析来自105个物种的Top2A序列，包括PSICalc算法，香农熵分析，和其他方法。我们的结果表明，发现了大的（10阶）相互依赖的簇，包括Top2A主要域的非近端位置。Further,第三个CTD特定簇，第四,第五阶，包括以前通过突变和生化分析分析的位置，已确定。其中一些集群与位置重合，当变异时，放松活动增加或减少。最后,低香农熵的位点(即，在给定位点氨基酸的低变异）被鉴定并定位为CTD中的关键位置。低熵位点包括磷酸化位点和带电位置。一起,这些结果有助于更清晰地了解CTD中的关键位置,并为进一步分析提供潜在的位点/区域.
