Department Biologie I - Botanik, Ludwig-Maximilians-Universität München, Planegg-Martinsried 82152, Germany.
Munich Centre for Integrated Protein Science, CIPSM, Ludwig-Maximilians-Universität München, Munich 81377, Germany.
Plant Physiol. 2019 Feb;179(2):601-615. doi: 10.1104/pp.18.01286. Epub 2018 Nov 28.
The evolutionarily conserved YidC/Oxa1/Alb3 proteins are involved in the insertion of membrane proteins in all domains of life. In plant mitochondria, individual knockouts of , , and are embryo-lethal. In contrast to other members of the protein family, OXA2a and OXA2b contain a tetratricopeptide repeat (TPR) domain at the C-terminus. Here, the role of Arabidopsis () OXA2b was determined by using viable mutant plants that were generated by complementing homozygous lethal T-DNA insertional mutants with a C-terminally truncated OXA2b lacking the TPR domain. The truncated-OXA2b-complemented plants displayed severe growth retardation due to a strong reduction in the steady-state abundance and enzyme activity of the mitochondrial respiratory chain complex IV. The TPR domain of OXA2b directly interacts with cytochrome oxidase subunit 2, aiding in efficient membrane insertion and translocation of its C-terminus. Thus, OXA2b is crucial for the biogenesis of complex IV in plant mitochondria.
进化上保守的 YidC/Oxa1/Alb3 蛋白参与所有生命领域的膜蛋白插入。在植物线粒体中，单个敲除 、 和 是胚胎致死的。与蛋白家族的其他成员不同，OXA2a 和 OXA2b 在 C 端含有一个四肽重复（TPR）结构域。在这里，通过使用可育突变体植物来确定拟南芥（）OXA2b 的作用，这些突变体植物通过用缺失 TPR 结构域的 C 端截断 OXA2b 来互补纯合致死 T-DNA 插入突变体而产生。截短的-OXA2b 互补植物由于线粒体呼吸链复合物 IV 的稳态丰度和酶活性严重降低而表现出严重的生长迟缓。OXA2b 的 TPR 结构域直接与细胞色素 c 氧化酶亚基 2 相互作用，有助于其 C 端的有效膜插入和易位。因此，OXA2b 对于植物线粒体中复合物 IV 的生物发生至关重要。
