Unique features of plant mitochondrial sulfhydryl oxidase.
The yeast and human mitochondrial sulfhydryl oxidases of the Erv1/Alr family have been shown to be essential for the biogenesis of mitochondria and the cytosolic iron sulfur cluster assembly. In this study we identified a likely candidate for the first mitochondrial flavin-linked sulfhydryl oxidase of the Erv1-type from a photosynthetic organism. The central core of the plant enzyme (AtErv1) exhibits all of the characteristic features of the Erv1/Alr protein family, including a redox-active YPCXXC motif, noncovalently bound FAD, and sulfhydryl oxidase activity. Transient expression of fusion proteins of AtErv1 and the green fluorescence protein in plant protoplasts showed that the plant enzyme preferentially localizes to the mitochondria. Yet AtErv1 has several unique features, such as the presence of a CXXXXC motif in its carboxyl-terminal domain and the absence of an amino-terminally localized cysteine pair common to yeast and human Erv1/Alr proteins. In addition, the dimerization of AtErv1 is not mediated by its amino terminus but by its unique CXXXXC motif. In vitro assays with purified protein and artificial substrates demonstrate a preference of AtErv1 for dithiols with a defined space between the thiol groups, suggesting a thioredoxin-like substrate.
Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
Alexander
A
Levitan
Avihai
A
Danon
Thomas
T
Lisowsky
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D015153:Blotting, Western; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D019281:Dimerization; D004926:Escherichia coli / Q000378:metabolism; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000201:enzymology* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000502:physiology*; D010957:Plasmids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013053:Spectrophotometry; D050862:Oxidoreductases Acting on Sulfur Group Donors
D004247:DNA; D018076:DNA, Complementary; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D010088:Oxidoreductases; D050862:Oxidoreductases Acting on Sulfur Group Donors