Structural studies of chromatin complexes

项目总结/摘要 组蛋白的翻译后修饰现已被确立为一种重要的机制， 调节真核细胞中的基因表达。然而，从结构和机制上理解 缺乏组蛋白修饰酶对其核小体底物的功能。这一缺陷限制了 它阻碍了对现有丰富的遗传、基因组和生物化学数据的解释， 靶向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。 我们致力于通过组蛋白修饰的结构测定来解决这些缺陷 与其生理核小体底物结合的酶。我们建议用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复合，使用 建立和新的方法来结晶这些复杂的，多组分的蛋白质/DNA复合物。 我们将补充我们的晶体学工作与使用冷冻电子显微镜的三维 染色质酶/核小体复合物结构测定。我们还计划用低温电子 显微镜处理天然的，兆道尔顿大小的组蛋白修饰酶的结构测定 配合物

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.