Structure of Eukaryotic Translation Elongation Factor 1

近年来，原核生物蛋白质合成的结构基础已被一系列可溶性翻译因子和核糖体本身的结构所阐明。 对真核生物蛋白质合成中更复杂和高度调控的步骤的类似理解才刚刚开始。 本项目的目标是了解真核生物翻译延伸因子1A（eEF 1A）的功能和调控的结构基础。 eEF 1A是一种原型G蛋白，不仅在翻译中发挥作用，而且在tRNA输出、病毒复制和细胞骨架组织中发挥作用。 因此，很明显，细胞需要调节eEF 1A的活性或水平以实现正常细胞生长。 再生的活性eEF 1A的鸟嘌呤核苷酸交换因子eEF 1B照亮我们的结构的酿酒酵母eEF 1A复合的催化片段的eEF 1B α亚基。 我们建议产生与1）GDP或GTP类似物GDPNP 2）氨酰基-tRNA（aa-tRNA）和GDPNP，3）完整鸟嘌呤核苷酸交换因子eEF 1B和4）肌动蛋白复合的eEF 1A的结构。作为一种G蛋白，eEF 1A根据GDP或GTP是否结合而在活性和非活性形式之间切换。 因此，了解这些形式之间的结构转换将有助于阐明与核糖体和aa-tRNA结合的调节。 GTP形式结合aa-tRNA，该复合物的结构将阐明结合核糖体A位点并感知适当的密码子-反密码子相互作用的复合物的总体三级结构。整个eEF 1AB复合物的结构将有助于确定eEF 1B γ亚基的功能，该亚基是一种在所有真核生物中高度保守的蛋白质，但最近才涉及可能调节翻译准确性和应激反应。 最后，越来越多的证据表明翻译装置的替代功能，特别是eEF 1A结合和捆绑肌动蛋白的能力，使我们扩展分析，以了解这种关联的结构基础。 链球菌酿酒酵母，eEF 1A上获得的结构信息可用于功能和调控的关键残基的分子遗传学分析。

Recently, the structural basis of protein synthesis in prokaryotes has been illuminated by a series of structures of the soluble translation factors and the ribosome itself. A similar understanding of the more complicated and highly regulated steps of eukaryotic protein synthesis is just beginning. The goal of this project is to understand the structural basis for the function and regulation of the eukaryotic translation Elongation Factor 1A (eEF1A). eEF1A is a prototypic G-protein that performs functions not only in translation but also tRNA export, viral replication and cytoskeletal organization. Thus, it is clear that the cell needs to modulate the activity or levels of eEF1A for normal cellular growth. The regeneration of active eEF1A by the guanine nucleotide exchange factor eEF1B is illuminated by our structure of Saccharomyces cerevisiae eEF1A complexed with the catalytic fragment of the eEF1Balpha subunit. We propose to produce structures of eEF1A in complex with 1) GDP or the GTP analogue GDPNP 2) aminoacyl-tRNA (aa-tRNA) and GDPNP, 3) the complete guanine nucleotide exchange factor eEF1B and 4) actin. As a G-protein, eEF1A switches between active and inactive forms The based on whether GDP or GTP is bound. Hence, understand the structural switch between the forms will help elucidate the regulation of binding to the ribosome and aa-tRNA. The GTP form binds aa-tRNA, and the structure of this complex will illuminate the overall tertiary structure of the complex that binds the ribosomal A-site and senses a proper codon-anticodon interaction. The structure of the entire eEF1AB complex will help determine the function of the eEF1Bgamma subunit, a protein highly conserved in all eucaryotes but only recently implicated in perhaps modulating translational accuracy and the stress response. Lastly, the growing evidence of alternative functions of the translational apparatus, and in particular the ability of eEF1A to bind and bundle actin, leads us to expand out analysis to understand the structural basis of this association. With S. cerevisiae, the structural information obtained on eEF1A can be utilized for molecular genetic analysis of the critical residues for function and regulation.