Abstract Inducible high-affinity copper uptake is key to homeostasis in Chlamydomonas reinhardtii. We generated cDNAs and updated gene models for four genes, CTR1, CTR2, CTR3, COPT1, encoding CTR-type transporters Chlamydomonas. The expression of CTR3 increases deficient cells response hypoxia or Ni2+ supplementation; this depends on the transcriptional activator CRR1. A element was identified by mutational analysis 5′ upstream region CTR1. Functional analyses identify CTR1 CTR2 as...

Abstract Here, we identify Arabidopsis thaliana Lumen Thiol Oxidoreductase1 (LTO1) as a disulfide bond–forming enzyme in the thylakoid lumen. Using topological reporters bacteria, deduced lumenal location for redox active domains of protein. LTO1 can partially substitute proteins catalyzing bond formation bacterial periplasm, which is topologically equivalent to plastid An insertional mutation within promoter associated with severe photoautotrophic growth defect. Measurements photosynthetic...

Heme plays fundamental roles as cofactor and signaling molecule in multiple pathways devoted to oxygen sensing utilization aerobic organisms. For cellular respiration, heme serves a prosthetic group electron transfer proteins redox enzymes. Here we report that the yeast Saccharomyces cerevisiae, heme-sensing mechanism translationally controls biogenesis of cytochrome c oxidase (COX), terminal mitochondrial respiratory chain enzyme. We show Mss51, COX1 mRNA-specific translational activator...

Protein synthesis has an overall error rate of approximately 10 -4 for each mRNA codon translated. The fidelity translation is mainly determined by two events: cognate amino acid:tRNA pairs aminoacyl-tRNA synthetases (aaRSs) and accurate selection aminoacyl-tRNAs (aa-tRNAs) the ribosome. To ensure faithful aa-tRNA synthesis, many aaRSs employ a proofreading (“editing”) activity, such as phenylalanyl-tRNA (PheRS) that hydrolyze mischarged Tyr-tRNA Phe . Eukaryotes maintain distinct PheRS...

Acute and chronic inflammation is characterized by increased reactive oxygen species (ROS) production, dysregulation of mitochondrial metabolism abnormal immune function contributing to cardiovascular diseases sepsis. Clinical epidemiological studies suggest potential beneficial effects dietary interventions in inflammatory but understanding how nutrients work remains insufficient. In the present study, we evaluated apigenin, an anti-inflammatory flavonoid abundantly found our diet,...

A 15.2-kDa polypeptide, encoded by the nuclear gene <i>PETO</i>, was identified as a novel cytochrome<i>b</i> ₆ <i>f</i> subunit in <i>Chlamydomonas reinhardtii</i>. The <i>PETO</i> product is <i>bona fide</i> subunit, V, of complex, because (i) it copurifies with other subunits early stages purification procedure, (ii) deficient mutants accumulating little and (iii) colocalizes cytochrome <i>f</i>, which migrates between stacked unstacked membrane regions upon state transition....

Summary Most cellular ATP is produced within the mitochondria from ADP and Pi which are delivered across inner‐membrane by specific nuclearly encoded polytopic carriers. In Saccharomyces cerevisiae, some of these carriers in particular ADP/ATP carrier, represented several related isoforms that distinct their pattern expression. Until now, only one mitochondrial carrier (mPic) form, MIR1 gene S. has been described. Here we show product YER053C ORF also participates delivery phosphate to...

Heme attachment to the apoforms of fungal mitochondrial cytochrome c and c1 requires activity heme lyases (CCHL CC1HL), which are enzymes with distinct substrate specificity. However, presence a single lyase in higher eukaryotes is suggestive broader Here, we demonstrate that yeast CCHL active toward non-cognate apocytochrome c1, i.e. promotes low levels conversion its holoform absence CC1HL. Moreover, human also displays specificity evident from ability substitute for both Multicopy genetic...

Three distinct systems (I, II, and III) for catalysis of heme attachment to <i>c</i>-type apocytochromes are known. The CcsA Ccs1 proteins required in system II the assembly bacterial plastid cytochromes <i>c</i>. A tryptophan-rich signature motif (WWD), also occurring CcmC CcmF found I, three histidinyl residues, all strictly conserved suggest a function handling. Topological analysis bacteria using <i>PhoA</i> and<i>LacZα</i> reporters placed WWD motif, residues His²¹²...

Mitochondrial apocytochrome <i>c</i> and <i>c</i>₁ are converted to their holoforms in the intermembrane space by attachment of heme cysteines C<i>XX</i>CH motif through activity assembly factors cytochrome lyase (CCHL CC₁HL). The maintenance sulfhydryls substrates a reduced state is critical for ligation heme. Factors that control redox chemistry reaction known bacteria plastids but not mitochondria. We have explored function Cyc2p, candidate component yeast show Cyc2p...

Here we report the characterization of Chlamydomonas reinhardtii gene ARG9, encoding plastid resident N-acetyl ornithine aminotransferase, which is involved in arginine synthesis. Integration an engineered ARG9 cassette chromosome nuclear arg9 mutant restores prototrophy. This suggests that could be used as a new selectable marker for transformation.

Mitochondrial complex I is the largest multimeric enzyme of respiratory chain. The lack a model system with facile genetics has limited molecular dissection assembly. Using Chlamydomonas reinhardtii as an experimental to screen for defects, we isolated, via forward genetics, amc1-7 nuclear mutants (for assembly mitochondrial I) displaying reduced or no activity. Blue native (BN)-PAGE and immunoblot analyses revealed that amc3 amc4 accumulate levels holoenzyme (950 kDa) while all other amc...

The Ccs1 gene, encoding a highly divergent novel component of system II type c-type cytochrome biogenesis pathway, is encoded by the previously defined CCS1 locus in Chlamydomonas reinhardtii. phoA and lacZalpha bacterial topological reporters were used to deduce model Synechocystis sp. 6803 homologue, CcsB. CcsB, therefore analogy Ccs1, possesses large soluble lumenal domain at its C terminus that tethered thylakoid membrane three closely spaced transmembrane domains N-terminal portion...

The c-type cytochromes are metalloproteins with a heme molecule covalently linked to the sulfhydryls of CXXCH heme-binding site. In plastids, at least six assembly factors required for attachment apo-forms cytochrome f and c6 in thylakoid lumen. CCS5, controlling plastid c assembly, was identified through insertional mutagenesis unicellular green alga Chlamydomonas reinhardtii. complementing gene encodes protein similarity Arabidopsis thaliana HCF164, which is membrane-anchored lumen-facing...

Thiol oxidation to disulfides and the reverse reaction, i.e., disulfide reduction free thiols, are under control of catalysts in vivo. Enzymatically assisted thiol-disulfide chemistry is required for biogenesis all energy-transducing membrane systems. However, until recently, this had only been demonstrated bacterial plasma membrane. Long considered be vacant, thylakoid lumen has now moved forefront photosynthesis research with realization that its proteome far more complicated than...

Mitochondrial genes can be artificially relocalized in the nuclear genome a process known as allotopic expression, such is case of mitochondrial cox2 gene, encoding subunit II cytochrome c oxidase (CcO). In yeast, allotopically expressed and able to restore respiratory growth cox2-null mutant if Cox2 carries W56R substitution within first transmembrane stretch. However, COX2W56R strain exhibits reduced rates lower steady-state CcO levels when compared wild-type yeast. Here, we investigated...