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Rubisco激活酶具有双重功能
作者:小柯机器人 发布时间:2020/9/29 10:40:43

德国马克斯普朗克研究所Manajit Hayer-Hartl等研究人员发现Rubisco激活酶具有双重功能。相关论文于2020年9月25日在线发表在《细胞》杂志上。

研究人员对蓝细菌Rubisco激活酶(Rca)(植物Rca的近缘同源物)进行了结构和机理分析。在Rca:Rubisco配合物中,Rca处于修复中的Rubisco催化位点上方,并将大Rubisco亚基(RbcL)的N末端尾部拉入六聚体孔中。相邻RbcL C末端的同时置换打开了抑制剂释放的催化位点。Rca与Rubisco的另一种相互作用是由类似于小Rubisco亚基的C末端结构域介导的。
 
这些结构域与N端AAA+六聚体一起,可确保Rca与Rubisco一起被包装成羧酶体。蓝细菌Rca是一种具有双重功能的蛋白质,即Rubisco修复和羧酶体组织。
 
据了解,Rubisco是光合作用中CO2固定的关键酶,很容易被抑制性磷酸糖而失活。抑制的Rubisco通过六聚体AAA+分子伴侣Rca进行构象修复,但过程尚不清楚。
 
附:英文原文

Title: Dual Functions of a Rubisco Activase in Metabolic Repair and Recruitment to Carboxysomes

Author: Mirkko Flecken, Huping Wang, Leonhard Popilka, F. Ulrich Hartl, Andreas Bracher, Manajit Hayer-Hartl

Issue&Volume: 2020-09-25

Abstract: Rubisco, the key enzyme of CO2 fixation in photosynthesis, is prone to inactivation by inhibitory sugar phosphates.Inhibited Rubisco undergoes conformational repair by the hexameric AAA+ chaperoneRubisco activase (Rca) in a process that is not well understood. Here, we performeda structural and mechanistic analysis of cyanobacterial Rca, a close homolog of plantRca. In the Rca:Rubisco complex, Rca is positioned over the Rubisco catalytic siteunder repair and pulls the N-terminal tail of the large Rubisco subunit (RbcL) intothe hexamer pore. Simultaneous displacement of the C terminus of the adjacent RbcLopens the catalytic site for inhibitor release. An alternative interaction of Rcawith Rubisco is mediated by C-terminal domains that resemble the small Rubisco subunit.These domains, together with the N-terminal AAA+ hexamer, ensure that Rca is packagedwith Rubisco into carboxysomes. The cyanobacterial Rca is a dual-purpose protein withfunctions in Rubisco repair and carboxysome organization.

DOI: 10.1016/j.cell.2020.09.010

Source: https://www.cell.com/cell/fulltext/S0092-8674(20)31151-X#%20

期刊信息
Cell:《细胞》,创刊于1974年。隶属于细胞出版社,最新IF:36.216
官方网址:https://www.cell.com/