STRUCTURAL STUDIES OF THE ELONGATOR COMPLEX

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 鉴定分泌组分的经典方法已经鉴定了膜运输所必需或支持的蛋白质。 然而，酵母细胞质，延长器（ELP）复合物与大多数已建立的参与者不同，因为它负调节分泌[1]。 虽然可能不是必需的，但负调节因子可以将分泌与细胞中的其他过程联系起来。 Elp复合物由六个亚基组成，可以生化分离成两个亚复合物（Elp 1/2/3 p和Elp 4/5/6p）。 该复合物已被证明具有依赖于两个亚复合物的体外赖氨酸乙酰转移酶活性，并且对于其调节晚期分泌的能力是重要的。 虽然Elp 1 - 3 p亚复合物具有明确的结构基序，表明支架和酶的功能，Elp 4 -6p的作用仍然未知。 Elp 4/5/6p复合物的结构将提供对Elp复合物的功能和进化的深入了解。 先前在CHESS的衍射实验应该晶体可以衍射到3.5A，但是大的晶胞、高镶嵌性（1-1.5）和熔融晶体使数据收集复杂化。 在筛选过程中，样品的蛋白水解产生了衍射显著改善至2.4 A的晶体。 基于这种蛋白水解的新结构在类似的条件下产生晶体，并正在测试其衍射质量。 [1]Rahl PB，Chen CZ，柯林斯RN（2005）Elp 1 p，FD疾病综合征蛋白的酵母同源物，独立于转录延伸负调节胞吐作用。Mol Cell 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.