In plant mitochondria, RNA editing involves the conversion of cytidines in genomic DNA into uridines corresponding RNA. Analysis cDNAs prepared by reverse transcription mitochondrial RNAs has shown that partially edited are present wheat mitochondria. The extent this partial as well its potential influence on protein sequence were studied along with expression a locus. sequence, expression, and unit containing four open reading frames (nad3, rps12, orf299, orf156), all cotranscribed same...

NADPH-dependent thioredoxin reductases (NTR) are homodimeric enzymes that reduce thioredoxins. Two genes encoding (AtNTRA and AtNTRB) were found in the genome of Arabidopsis thaliana. These originated from a recent duplication event encoded proteins highly homologous. Previously, AtNTRA was shown to encode dual targeted cytosol mitochondrial protein. Here, we show AtNTRB gene encodes two mRNAs, presumably by initiating transcription at different sites. The longer mRNA precursor polypeptide...

NADH-ubiquinone oxidoreductase (Complex I, EC 1.6.5.3) is the largest complex of mitochondrial respiratory chain. In eukaryotes, it composed more than 40 subunits that are encoded by both nuclear and genomes. Plant Complex I differs from enzyme described in other most notably due to large number plant-specific membrane arm complex. The elucidation assembly pathway has been a long-standing research aim cellular biochemistry. We report study Arabidopsis mutants using combination Blue-Native...

RNA editing, converting cytidines (C) to uridines (U) at specific sites in the transcripts of mitochondria and plastids, plays a critical role organelle gene expression land plants. Recently pentatricopeptide repeat (PPR) proteins were identified as site-specific recognition factors for editing. In this study, we characterized an empty pericarp7 mutant (emp7) Zea mays (maize), which confers embryo-lethal phenotype. emp7 mutants, mitochondrial functions are seriously perturbed, resulting...

Abstract The Arabidopsis type II peroxiredoxin (PRXII) family is composed of six different genes, five which are expressed. On the basis nucleotide and protein sequences, we were able to define three subgroups among PRXII family. first subgroup AtPRXII-B, -C, -D, highly similar localized in cytosol. AtPRXII-B ubiquitously More striking specific expression AtPRXII-C AtPRXII-D pollen. second comprises mitochondrial AtPRXII-F, corresponding gene expressed constitutively. We show that AtPRXII-E,...

The maturation of c-type cytochromes requires the covalent ligation heme cofactor to reduced cysteines CXXCH motif apocytochromes. In contrast mitochondria other eukaryotes, plant follow a pathway close that found in alpha- and gamma-proteobacteria. We identified nuclear-encoded protein, AtCCMH, Arabidopsis thaliana ortholog bacterial CcmH/CycL proteins. bacteria, CcmH thioredoxin CcmG are components periplasmic thio-reduction proposed maintain apocytochrome c state. AtCCMH is located...

Two Arabidopsis thaliana genes (HCC1 and HCC2), resulting from a duplication that took place before the emergence of flowering plants, encode proteins with homology to SCO involved in copper insertion during cytochrome c oxidase (COX) assembly other organisms. Heterozygote HCC1 mutant plants produce 25% abnormal seeds defective embryos arrested at heart or torpedo stage. These lack COX activity, suggesting requirement early stages plant development is related its function. Homozygote HCC2...

Three reading frames called ccmF(N1), ccmF(N2), and ccmF(c) are found in the mitochondrial genome of Arabidopsis. These sequences similar to regions bacterial gene ccmF involved cytochrome c maturation. genes always absent from animal fungi genomes but land plant several evolutionary distant eukaryotes. In Arabidopsis, ccmF(N2) despite absence a classical initiation codon is not pseudo gene. The 3 Arabidopsis expressed at protein level. Their products integral proteins inner membrane with...

ABC transporters make a large and diverse family of proteins found in all phylae. AtCCMA is the nucleotide binding domain novel Arabidopsis mitochondrial transporter. It encoded nucleus imported into mitochondria. Sub-organellar topology studies find bound to inner membrane, facing matrix. exhibits an ATPase activity, ATP/Mg2+ can facilitate its dissociation from membranes. Blue Native PAGE shows that it part 480-kDa complex. Yeast two-hybrid assays reveal interactions between domains CcmB,...

The maturation of <i>c</i>-type cytochromes requires the covalent attachment heme cofactor to apoprotein. For this process, plant mitochondria follow a pathway distinct from that animal or yeast mitochondria, closer found in α- and γ-proteobacteria. We report first characterization nuclear-encoded component, namely AtCCME, the<i>Arabidopsis thaliana</i> orthologue CcmE, periplasmic chaperone bacteria. AtCCME is targeted its N-terminal signal peptide cleaved upon import. peripheral protein...

We present the nucleotide sequence of gene encoding subunit 3 cytochrome c oxidase in Chondrus crispus, first report on a mitochondrial from red alga. Amino acid alignment with homologous proteins shows that tryptophan is specified by UGA, as code most organisms other than green plants. However, phylogenetic analyses cox3 amino and sequences indicate C. crispus COX3 related to green-plant lineage. No RNA editing was detected corresponding transcript. As only known photosynthetic eukaryotes...

The maturation of tRNA precursors involves the 5' cleavage leader sequences by an essential endonuclease called RNase P. Beyond ancestral ribonucleoprotein (RNP) P, a second type P PRORP (protein-only P) evolved in eukaryotes. current view on distribution cells is that multiple RNPs, PRORPs or combination both, perform specialised activities different compartments where gene expression occurs. Here, we identify single encoding green alga Chlamydomonas reinhardtii while no RNP found. We show...

Components of some protein complexes present in the inner membrane mitochondria are encoded both nuclear and mitochondrial genomes, correct sorting assembly these proteins is necessary for proper respiratory function. Recent studies yeast suggest that Oxa1p, a conserved between prokaryotes eukaryotes, an essential factor into membranes. We previously identified AtOXA1, Arabidopsis homologue OXA1 by functional complementation oxa1– mutant. In this study, we investigated genomic organization...

In land plant mitochondria, c ‐type cytochromes are assembled via a mechanism similar to that found in Gram‐negative bacteria and different from used by mitochondria other eukaryotes. The wheat mitochondrial genome encodes CCM (for cytochrome maturation) proteins, among them CcmF C , protein the C‐terminal part of bacterial CcmF. gene is transcribed into 1.7 kb transcript at steady state. However, 3′ termini were occur upstream deduced termination codon. This discrepancy was solved RNA...