STRUCTURE OF HEAT SHOCK TRANSCRIPTION FACTOR FROM YEAST

我们研究的主要目标是了解蛋白质如何特异性地 识别DNA以及这种相互作用如何调节转录 调控 热休克转录因子（HSF）已被选为 由于其重要的生物学作用，以及其独特的 结构 HSF是热休克的转录激活因子 反应，一种进化上保守的机制，保护细胞免受 加热和其它环境和化学刺激。 HSF在所有 真核生物，从酵母到人类。 HSF包含一个新的蛋白质家族，具有高度保守的DNA 结合结构域和新的三聚化结构域。 最近的结构 DNA结合结构域显示其具有类似于螺旋的拓扑结构 蛋白质如分解代谢物激活蛋白（CAP）和组蛋白H5。 尽管有这种相似性，HSF不同于经典的螺旋-转角-螺旋 基序：取代两个识别之间的三个氨基酸的转折 HSF有一个由五个氨基酸组成的环，这导致了HSF中的一个主要变化。 两个螺旋之间的夹角。 HSF可以构成“子类”， 螺旋-转角-螺旋基序。 所述三聚化结构域包括三聚化结构域。 螺旋状卷曲螺旋。 HSF是唯一已知的 三聚体DNA结合蛋白，导致有趣的问题， 与DNA结合。 研究HSF大小和复杂性的蛋白质的关键是 获得适合物理研究的较小碎片。 的 这项建议的具体目标集中在DNA结合的研究， 三聚化结构域，并且它们包括： 三聚体DNA结合蛋白的生物化学和物理行为， 继续进行成功的结晶研究， 遗传学作为结构和物理的补充工具， 这些领域的特征。 这些研究将导致长期 长期目标是了解像HSF这样的三聚体蛋白如何相互作用 用DNA

The major goal of our research is to understand how proteins specifically recognize DNA and how this interaction modulates transcriptional regulation. Heat shock transcription factor (HSF) has been chosen for study because of its important biological role, as well as its unique structure. HSF is the transcriptional activator for the heat shock response, an evolutionarily conserved mechanism which protects cells from heat and other environmental and chemical stimuli. HSF is found in all eukaryotes, from yeast to humans. HSF encompasses a new family of proteins, with a highly conserved DNA binding domain and a novel trimerization domain. The recent structure of the DNA binding domain shows that it has a topology similar to helix proteins such as catabolite activator protein (CAP) and histone H5. Despite this similarity, HSF differs from the classical helix-turn-helix motif: instead of the three amino acid turn between the two recognition helices, HSF has a loop of five amino acids, which causes a major change in the angle between the two helices. HSF may constitute a 'sub-class" of the helix-turn-helix motif. The trimerization domain includes a triple- stranded alpha-helical coiled-coil. HSF is the only known example of a trimeric DNA binding protein, leading to interesting questions about how it binds to DNA. The key to studying a protein of the size and complexity of HSF is to obtain smaller fragments that are amenable to physical studies. The specific aims of this proposal focus on a study of the DNA binding and trimerization domains, and they include: characterization of the biochemical and physical behavior of a trimeric DNA binding protein, continuation of the successful crystallization studies, and utilization of genetics as a complementary tool to the structural and physical characterization of these domains. These studies will lead to the long term goal of understanding how a trimeric protein like HSF can interact with DNA.