Structural studies of chromatin complexes

项目摘要/摘要 组蛋白的翻译后修饰现在被确立为一种重要的机制 调控真核细胞中的基因表达。然而，结构性和机械性地理解如何 组蛋白修饰酶在其核小体底物上的作用是缺乏的。这一缺点限制了 对现有的丰富的遗传、基因组和生化数据的解释，阻碍了 针对与包括癌症在内的人类疾病相关的许多染色质酶的新疗法。 我们致力于通过确定组蛋白修饰的结构来解决这些缺陷。 与其生理核小体底物结合的酶。我们建议确定X射线晶体结构 与人类疾病相关的组蛋白修饰酶与核小体的复合体，使用 已建立和创新的方法来结晶这些复杂的、多组分的蛋白质/DNA复合体。 我们将使用低温电子显微镜来补充我们的结晶学努力，用于三维 染色质酶/核小体复合体的结构测定。我们还计划使用低温电子 显微技术用于测定天然百万吨级组蛋白修饰酶的结构 复合体。

Project Summary/Abstract The post-translational modification of histone proteins is now established as an important mechanism for regulating gene expression in eukaryotic cells. However, a structural and mechanistic understanding of how the histone modification enzymes function on their nucleosome substrate is lacking. This shortcoming limits interpretation of the wealth of genetic, genomic and biochemical data available, and it hampers development of new therapeutics that target the many chromatin enzymes associated with human diseases including cancer. We are focused on addressing these deficiencies through structure determination of histone modification enzymes bound to their physiological nucleosome substrate. We propose to determine X-ray crystal structures of histone modification enzymes associated with human diseases in complex with the nucleosome, using established and novel approaches to crystallize these complicated, multicomponent protein/DNA complexes. We will complement our crystallographic efforts with use of cryoelectron microscopy for three-dimensional structure determination of chromatin enzyme/nucleosome complexes. We also plan to use cryoelectron microscopy to tackle structure determination of native, megadalton sized histone modification enzyme complexes.