An Young Jun, Na Jung-Hyun, Kim Myung-Il, Cha Sun-Shin
Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.
Department of Marine Biotechnology, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea.
J Microbiol. 2015 Oct;53(10):711-7. doi: 10.1007/s12275-015-5417-5. Epub 2015 Oct 2.
Lon proteases degrade defective or denature proteins as well as some folded proteins for the control of cellular protein quality. There are two types of Lon proteases, LonA and LonB. Each consists of two functional components: a protease component and an ATPase associated with various cellular activities (AAA+ module). Here, we report the 2.03 -resolution crystal structure of the isolated AAA+ module (iAAA+ module) of LonB from Thermococcus onnurineus NA1 (TonLonB). The iAAA+ module, having no bound nucleotide, adopts a conformation virtually identical to the ADP-bound conformation of AAA+ modules in the hexameric structure of TonLonB; this provides insights into the ATP-independent proteolytic activity observed in a LonB protease. Structural comparison of AAA+ modules between LonA and LonB revealed that the AAA+ modules of Lon proteases are separated into two distinct clades depending on their structural features. The AAA+ module of LonB belongs to the -H2 & Ins1 insert clade (HINS clade)- defined for the first time in this study, while the AAA+ module of LonA is a member of the HCLR clade.
Lon蛋白酶可降解有缺陷或变性的蛋白质以及一些折叠蛋白，以控制细胞蛋白质质量。Lon蛋白酶有两种类型，即LonA和LonB。每种都由两个功能组件组成：一个蛋白酶组件和一个与各种细胞活动相关的ATP酶（AAA+模块）。在此，我们报告了来自嗜热栖热袍菌NA1（TonLonB）的LonB分离AAA+模块（iAAA+模块）的2.03埃分辨率晶体结构。该iAAA+模块未结合核苷酸，其构象与TonLonB六聚体结构中与ADP结合的AAA+模块构象几乎相同；这为在LonB蛋白酶中观察到的不依赖ATP的蛋白水解活性提供了见解。LonA和LonB的AAA+模块的结构比较表明，Lon蛋白酶的AAA+模块根据其结构特征分为两个不同的进化枝。LonB的AAA+模块属于本研究首次定义的-H2 & Ins1插入进化枝（HINS进化枝），而LonA的AAA+模块是HCLR进化枝的成员。
