STRUCTURE OF YEAST RNA POLYMERASE II

这项拟议的研究的目标是确定X射线 RNA聚合酶II及其与核的络合物的结构 原子分辨率的酸和辅助蛋白质因子。问题 是具有挑战性的，因为聚合酶本身就包含15个多肽 总质量接近60万道尔顿，并增加了 辅助因子使多肽的数量翻了一番， 蛋白质质量。这个问题的解决需要结合以下几个方面 生化研究、电子和X射线结晶学。八大类型 RNA聚合酶II的晶体现在都在手中，天然的晶体 酶，与DNA和RNA的共晶体，DNA和RNA都在 转录激活状态，有TFIIB，有TFIIE，有 额外的聚合酶亚基RPB4和RPB7，以及与 紧密结合的抑制剂a-Amanitin。最近的进展包括 分辨率为6.5E的包络和相位，以及最近收集的 几种新的重原子团簇与RNA Pol II络合。 现在预后很好，很快就达到了一个很高的 分辨率结构。

The goal of the proposed research is to determine the X-ray structures of RNA polymerase II and of its complexes with nucleic acids and auxiliary protein factors at atomic resolution. The problem is challenging, since the polymerase alone comprises 15 polypeptides with a total mass of nearly 600,000 Dalton, and addition of the auxiliary factors doubles both the number of polypeptides and the protein mass. Solution of the problem requires a combination of biochemical studies, electron and X-ray crystallography. Eight types of RNA polymerase II crystal are now in hand, crystals of the native enzyme, and cocrystals with DNA, with RNA, with both DNA and RNA in the transcriptionally active state, with TFIIB, with TFIIE, with the additional polymerase subunits RPB4 and RPB7, and with the tight-binding inhibitor a-amanitin. Recent progress includes a low resolution envelope and phases to 6.5 E, and the recent collection of several novel heavy atom cluster complexed with RNA Pol II. The prognosis is now very good for the rapid achievement of a high resolution structure.