STRUCTURAL STUDIES OF THE ELONGATOR COMPLEX

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 经典的识别分泌成分的方法已经识别出对膜运输至关重要或支持的蛋白质。然而，酵母细胞质Elongator(ELP)复合体不同于大多数已建立的参与者，因为它负向调节分泌[1]。虽然可能不是必需的，但负调节因子可以将分泌与细胞内的其他过程联系在一起。ELP复合体由六个亚基组成，可生化分离为两个亚复合体(Elp1/2/3p和Elp4/5/6p)。该复合体在体外具有赖氨酸乙酰转移酶活性，该活性依赖于这两个亚复合体，并且对于其调节晚期分泌的能力是重要的。虽然Elp1-3p亚复合体有明确的结构基序，暗示着支架和酶功能，但Elp4-6p的作用尚不清楚。Elp4/5/6P复合体的结构将提供对ELP复合体的功能和进化的洞察。 CHESS已有的衍射实验表明，晶体的衍射率可达3.5A，但大晶胞、高马赛克(1-1.5)和熔融晶体的数据采集比较复杂。在筛选过程中，样品的蛋白质分解产生了晶体，其衍射率显著提高到2.4A。基于这种蛋白质分解的新结构使晶体处于类似的条件下，并正在测试其衍射质量。 [1]Rahl PB，Chen CZ，Collins RN(2005)Elp1p，FD疾病综合征蛋白的酵母同源物，独立于转录延长负调控胞吐。摩尔细胞17：841-853。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Classical approaches identifying secretory components have identified proteins that are essential or supportive of membrane traffic. However, the yeast cytoplasmic, Elongator (Elp) complex differs from most established players, in that it negatively regulates secretion [1]. While perhaps not essential, a negative regulator can tie secretion to other processes in the cell. The Elp complex is composed of six-subunits that can be biochemically separated into two subcomplexes (Elp1/2/3p and Elp4/5/6p). The complex has been shown to have in vitro lysine acetyltransferase activity that is dependent on both subcomplexes, and is important for its ability to regulate late secretion. While the Elp1-3p subcomplex has clear structural motifs that suggest scaffolding and enzymatic functions, Elp4-6p's role remains unknown. A structure of the Elp4/5/6p complex will provide insight into the function and evolution of the Elp complex. Prior diffraction experiments at CHESS should crystals could diffract to 3.5A, but large unit cell, high mosaicity (1-1.5) and fused crystals complicated data collection. During screening proteolysis of samples yielded crystals with significantly improved diffraction to 2.4A. New constructs based on this proteolysis give crystals in similar conditions and are being tested for their diffraction quality. [1] Rahl PB, Chen CZ, Collins RN (2005) Elp1p, the yeast homolog of the FD disease syndrome protein, negatively regulates exocytosis independently of transcriptional elongation. Mol Cell 17: 841-853.