3D Gel Map of Arabidopsis Complex I

Abstract

Complex I has a unique structure in plants and includes extra subunits. Here, we present a novel study to define its protein constituents. Mitochondria were isolated from Arabidopsis thaliana cell cultures, leaves, and roots. Subunits of complex I were resolved by 3D blue-native (BN)/SDS/SDS-PAGE and identified by mass spectrometry. Overall, 55 distinct proteins were found, seven of which occur in pairs of isoforms. We present evidence that Arabidopsis complex I consists of 49 distinct types of subunits, 40 of which represent homologs of bovine complex I. The nine other subunits represent special proteins absent in the animal linage of eukaryotes, most prominently a group of subunits related to bacterial gamma-type carbonic anhydrases. A GelMap is presented for promoting future complex I research in Arabidopsis thaliana.

The Pentatricopeptide Repeat Proteins TANG2 and ORGANELLE TRANSCRIPT PROCESSING439 Are Involved in the Splicing of the Multipartite nad5 Transcript Encoding a Subunit of Mitochondrial Complex I

“…In plants, it is composed of more than 40 subunits, nine encoded by mitochondrial genes (nad1-nad4, nad4L, nad5-nad7, and nad9) and the others by nuclear genes. Most of the mitochondrially encoded subunits are part of the membrane arm, with the exception of Nad7 and Nad9, which belong to the hydrophilic peripheral arm (Peters et al, 2013). The assembly of subunits of nuclear and mitochondrial origins to form a functional complex requires complex mechanisms to coordinate the expression of genes from two physically separate genetic systems (Barkan, 2011) and a tight control of the processing of the mitochondrial transcripts by nuclearly encoded RNA-binding cofactors.…”

Plant Mitochondrial Omics: State-of-the-Art Knowledge

“…The proteins that constitute complex I is encoded by two genomes: nine have a mitochondrial genetic origin in higher plants, while the remaining subunits are encoded in the nucleus. Recently, composition of complex I has been investigated intensively in humans (Ugalde et al 2004 ;Vogel et al 2007 ;Remacle et al 2008 ;Peters et al 2013 ) in the vascular plants Arabidopsis thaliana and Oryza sativa (Heazlewood et al 2003b , c ;Meyer et al 2008 ) and in the green algae Chlamydomonas reinhardtii (Cardol et al 2004(Cardol et al , 2005. In Arabidopsis , 42 distinct complex I subunits are known and some of them interrupted with class II introns.…”

“…These class II introns are removed posttranscriptionally by mitochondrial CAF-like splicing factor 1 (mCSF1; At4 g31010) (Meyer et al 2008 ;Zmudjak et al 2013 ). The complex I subunits of Arabidopsis thaliana are highly conserved across the organisms; 40 out of 49 subunits have homology with bovine complex I, including 14 orthologues to the prokaryotic enzyme that constitute the 'core' subunits of complex I (Cardol et al 2005 ;Peters et al 2013 ). The function of most of the extra subunits in mitochondria is yet unclear, but it is speculated that they might be important for enzyme stabilization or protection of the complex towards reactive oxygen species (ROS) (Vogel et al 2007 ).…”

Respiratory-deficient mutants of the unicellular green alga Chlamydomonas: A review

“…1000 kDa, it comprises 44-45 subunits in Bos taurus [2,3]. In Arabidopsis thaliana, 49 distinct subunits have been identified [4], 40 of which are homologous to mammal subunits [5]. In…”