STRUCTURE OF THE SEC13-SEC16 EDGE ELEMENT

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 祖先共生分子1(ACE1)蛋白组装COPII囊泡和核孔复合体的网状层。ACE1蛋白Sec31和Sec13形成2：2的四聚体，形成COPII外层的边缘元件。在本研究中，我们报告了COPII辅助蛋白Sec16也含有ACE1。在2.7°分辨率下，计算了Sec16与Sec13的中心结构域的165kD晶体结构。Sec16和Sec13还形成了2：2的四聚体，这是COPII系统的另一个边缘元件。在Sec13Sec31和Sec13Sec16的先前结构中，都存在ACE1ACE1界面上的结构域交换。防止结构域互换的Sec31突变体采用了前所未有的层叠结构，以2.8？分辨率解决。我们的体内数据表明，Sec31的ACE1元件可以在功能上取代Sec16的ACE1元件。我们的数据支持Sec16作为COPII系统的支架和Sec13Sec31外套的模板。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Ancestral coatomer element 1 (ACE1) proteins assemble latticework coats for COPII vesicles and the nuclear pore complex. The ACE1 pro- tein Sec31 and Sec13 make a 2:2 tetramer that forms the edge element of the COPII outer coat. In this study, we report that the COPII accessory protein Sec16 also contains an ACE1. The 165-kD crystal structure of the central domain of Sec16 in complex with Sec13 was solved at 2.7-¿ resolution. Sec16 and Sec13 also make a 2:2 tetramer, another edge element for the COPII system.Domain swapping at the ACE1ACE1 interface is ob- served both in the prior structure of Sec13Sec31 and in Sec13Sec16. A Sec31 mutant in which domain swap- ping is prevented adopts an unprecedented laminated structure, solved at 2.8-¿ resolution. Our in vivo data suggest that the ACE1 element of Sec31 can functionally replace the ACE1 element of Sec16. Our data support Sec16 as a scaffold for the COPII system and a template for the Sec13Sec31 coat.