Isolation and characterization of the pea cytochrome c oxidase Vb gene

Abstract

Three copies of the gene that encodes cytochrome c oxidase subunit Vb were isolated from the pea (PscoxVb-1, PscoxVb-2, and PscoxVb-3). Northern Blot and reverse transcriptase-PCR analyses suggest that all 3 genes are transcribed in the pea. Each pea coxVb gene has an N-terminal extended sequence that can encode a mitochondrial targeting signal, called a presequence. The localization of green fluorescent proteins fused with the presequence strongly suggests the targeting of pea COXVb proteins to mitochondria. Each pea coxVb gene has 5 intron sites within the coding region. These are similar to Arabidopsis and rice, although the intron lengths vary greatly. A phylogenetic analysis of coxVb suggests the occurrence of gene duplication events during angiosperm evolution. In particular, 2 duplication events might have occurred in legumes, grasses, and Solanaceae. A comparison of amino acid sequences in COXVb or its counterpart shows the conservation of several amino acids within a zinc finger motif. Interestingly, a homology search analysis showed that bacterial protein COG4391 and a mitochondrial complex I 13 kDa subunit also have similar amino acid compositions around this motif. Such similarity might reflect evolutionary relationships among the 3 proteins.

On the bacterial ancestry of mitochondria: new insights with triangulated approaches

“…1), as well as other proteins that participate in the assembly of complex IV (SCO, CtaA/Cox15 [23]), complex III (Cbp3 chaperone [23]) and their substrate cytochrome c (heme lyase CcmF). Among traits not evaluated before, we considered a bacterial zinc-finger protein that is the likely ancestor of subunit Vb of complex IV [24] and a cysteine signature in a conserved C-terminal region of COX1 [25] (Box1). The latter was considered for its common presence in alphaproteobacteria with reduced genomes including Rickettiales and early branching eukaryotes (Supplementary Table S2).…”

Divalent Metal Ions in Plant Mitochondria and Their Role in Interactions with Proteins and Oxidative Stress-Induced Damage to Respiratory Function

“…Instead, the 74 proteins identified are likely to associate with Zn through a variety of mechanisms. Some examples of these include proteins that contain Zn fingers (cytochrome c oxidase 5b; Kubo et al, 2006), that use Zn as a cofactor (nucleoside diphosphate kinase, mitochondrial processing peptidase b; Parks and Agarwal, 1973;Luciano and Geli, 1996), that are inhibited by Zn (methylcrotonyl-CoA carboxylase, 2-oxoglutarate dehydrogenase; Diez et al, 1994;Brown et al, 2000), or that interact with divalent cations (malic enzyme, Glu dehydrogenase, succinate dehydrogenase Fe-S subunits; Massarini and Cazzulo, 1975;Kindt et al, 1980). Proteins with no known association with Zn ions, such as the ATP synthase subunits, were also found.…”

Multiple approaches of cellular metabolism define the bacterial ancestry of mitochondria

“…S2A). We then settled on a representative set of 20 traits including the bacterial Zn-finger precursor of Cox5B ( 26 ) and a cysteine signature in a conserved C-terminal region of catalytic COX subunit 1 (COX1) ( 27 ). The latter trait was chosen for its common presence in alphaproteobacteria with reduced genomes including Rickettsiales (table S3).…”