STRUCTURAL STUDIES OF INNER KINETOCHORE PROTEIN COMPLEXES FROM BUDDING YEAST

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 我们的目标是确定芽殖酵母内部动粒组分的结构，长期目标是建立动粒分子组织的完整图像。 在芽殖酵母的情况下，内部动粒的组分-即与着丝粒DNA直接或非常密切相关的蛋白质-包括着丝粒结合因子1和3（Cbf 1和CBF 3），Mif 2，一种“特化”核小体，其中H3被称为Cse 4（人类CENP-A）的着丝粒特异性组蛋白取代，以及核小体组装因子Scm 3。 在2009年期间，我们确定了Ndc 10的结构，这是CBF 3的主要成分。 在2010年期间，我们已经确定了Cse 4核小体的组装状态的结构：Cse 4，H4和Scm 3片段的三元复合物（分辨率为2.3）和Cse 4：H4异源四聚体（分辨率为2.6）。 这两种结构有助于我们对动粒组装途径的理解。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The goal is to determine the structures of components of the budding-yeast inner kinetochore, with the longer-term objective of creating a complete picture of kinetochore molecular organization. In the case of budding yeast, the components of the inner kinetochore -- that is, the proteins directly or very closely associated with centromeric DNA -- include centromere-binding factors 1 and 3 (Cbf1 and CBF3), Mif2, a "specialized" nucleosome in which H3 is replaced by a centromere-specific histone known as Cse4 (CENP-A in humans), and a nucleosome assembly factor, Scm3. During 2009, we determined the structure of Ndc10, a major component of CBF3. During 2010, we have determined structures of assembly states of the Cse4 nucleosome: a three-way complex of Cse4, H4, and a fragment of Scm3 (at 2.3 ¿ resolution) and a Cse4:H4 heterotetramer (at 2.6 ¿ resolution). The two structures contribute to our growing understanding of pathways of kinetochore assembly.