OXA2b is Crucial for Proper Membrane Insertion of COX2 during Biogenesis of Complex IV in Plant Mitochondria

Abstract

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 OXA1a, OXA2a, and OXA2b 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 (Arabidopsis thaliana) OXA2b was determined by using viable mutant plants that were generated by complementing homozygous lethal OXA2b 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 c 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.

Rapid Single-Step Affinity Purification of HA-Tagged Plant Mitochondria

“…Recently, analyses of mitochondrial proteome content, complexome composition, posttranslational modifications, energy metabolism, OXPHOS complex formation and function, protein translocation, and metabolite shuttles have been conducted to further our understanding of mitochondrial metabolism in Arabidopsis (König et al, 2014;Fromm et al, 2016;De Col et al, 2017;Rao et al, 2017;Senkler et al, 2017;Porcelli et al, 2018;Hu et al, 2019;Kolli et al, 2019;Meyer et al, 2019;Nickel et al, 2019). Many of these analyses required the isolation of intact mitochondria.…”

Rapid single-step affinity purification of HA-tagged mitochondria from Arabidopsis thaliana

“…Recently, analyses of mitochondrial proteome content, complexome composition, post-translational modifications, energy metabolism, OXPHOS complex formation and function, protein translocation, and metabolite shuttles have been conducted to further our understanding of mitochondrial metabolism in Arabidopsis (König et al, 2014; Fromm et al, 2016; De Col et al, 2017; Rao et al, 2017; Senkler et al, 2017; Porcelli et al, 2018; Hu et al, 2019; Kolli et al, 2019; Meyer et al, 2019; Nickel et al, 2019). Many of these analyses required the isolation of intact mitochondria.…”

Biochemistry of Copper Site Assembly in Heme-Copper Oxidases: A Theme with Variations

“…In fungi and animals, two proteins from the Oxa family have been described: Oxa1 and CoxOxa1 inserts the nascent N-terminal transmembrane helix, and Cox18, which is specific for Cox II, translocates the C-terminal soluble domain [62]. Plants contain four Oxa homologs, among them, Oxa1a is the N-terminal insertase and Oxa2b is the translocase [64].…”