Structural Characterization of the N-Terminal Domain of the Dictyostelium discoideum Mitochondrial Calcium Uniporter
Structural Characterization of the N-Terminal Domain of the Dictyostelium discoideum Mitochondrial Calcium Uniporter
复制标题
盘基网柄菌线粒体钙单向转运蛋白 N 端结构域的结构表征
作者：
Yuan Yuan;Cao Chan;Wen Maorong;Li Min;Dong Ying;Wu Lijie;Wu Jian;Cui Tanxing;Li Dianfan;Chou James J.;OuYang Bo
线粒体钙单向转运体（MCU）在线粒体钙摄取到基质中起关键作用。在后生动物中，单向转运蛋白是一个严格调控的多组分系统，包括成孔亚基MCU和几个调节子（MICU 1，MICU 2，EMRE）。后生动物MCU的钙传导活性需要单跨膜蛋白EMRE。然而，盘基网柄藻（Dd）开发了一种简化的单向转运体，其中单独的成孔MCU（DdMCU）是钙内流所必需和足够的。在这里，我们报告的N-末端域（NTD）的DdMCU在1.7 μ m分辨率的晶体结构。DdMCU-NTD含有四个螺旋和两条折叠的链，这与其他MCU-NTD同源物的已知结构完全不同。在溶液中的DdMCU-NTD的生物化学和生物物理分析表明，该结构域存在的低聚物，最有可能作为一个五聚体或六聚体。诱变结果表明，DdMCU-NTD的自组装过程中有Asp 60、Glu 72和Glu 74等酸性残基参与。有趣的是，低聚物复合物容易解离为较低阶的低聚物在钙的存在下。我们建议，钙触发的NTD的解离调节通道活动的DdMCU的一个未知的机制。
The mitochondrial calcium uniporter (MCU) plays a critical role in the mitochondrial calcium uptake into the matrix. In metazoans, the uniporter is a tightly regulated multi-component system including the pore-forming subunit MCU and several regulators (MICU1, MICU2, EMRE). The calcium-conducting activity of metazoan MCU requires the single-transmembrane protein EMRE. Dictyostelium discoideum (Dd), however, developed a simplified uniporter for which the pore-forming MCU (DdMCU) alone is necessary and sufficient for calcium influx. Here, we report a crystal structure of the N-terminal domain (NTD) of DdMCU at 1.7 Å resolution. The DdMCU-NTD contains four helices and two strands arranged in a fold that is completely different from the known structures of other MCU-NTD homologs. Biochemical and biophysical analyses of DdMCU-NTD in solution indicated that the domain exists as oligomers, most probably as a pentamer or hexamer. Mutagenesis showed that the acidic residues Asp60, Glu72 and Glu74, which appeared to mediate the parallel interface as observed in the crystal structure, participated in the self-assembly of DdMCU-NTD. Intriguingly, the oligomeric complex readily dissociated to lower-order oligomers in the presence of calcium. We propose that the calcium-triggered dissociation of NTD regulates the channel activity of DdMCU by a yet unknown mechanism.
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线粒体钙单向转运蛋白双环离子选择性过滤器的离子和抑制剂结合。
DOI：
10.1073/pnas.1620316114
发表时间：
2017-04-04
影响因子：
11.1
作者：
Cao, Chan;Wang, Shuqing;Chou, James J.
通讯作者：
Chou, James J.
影响因子：
8.8
作者：
Vais H;Mallilankaraman K;Mak DD;Hoff H;Payne R;Tanis JE;Foskett JK
通讯作者：
Foskett JK
DOI：
10.1107/s0907444909038207
发表时间：
2010-04
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Walden H
通讯作者：
Walden H
DOI：
10.1016/s0021-9258(19)73805-8
发表时间：
1962-08
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
F. D. Vasington;J. V. Murphy
通讯作者：
F. D. Vasington;J. V. Murphy
影响因子：
3.9
作者：
R. Denton;J. G. Mccormack
通讯作者：
R. Denton;J. G. Mccormack