Phylogenetics and enzymology of plant quiescin sulfhydryl oxidase.
Quiescin Sulfhydryl Oxidase (QSOX), a catalyst of disulfide bond formation, is found in both plants and animals. Mammalian, avian, and trypanosomal QSOX enzymes have been studied in detail, but plant QSOX has yet to be characterized. Differences between plant and animal QSOXs in domain composition and active-site sequences raise the question of whether these QSOXs function by the same mechanism. We demonstrate that Arabidopsis thaliana QSOX produced in bacteria is folded and functional as a sulfhydryl oxidase but does not exhibit the interdomain electron transfer observed for its animal counterpart. Based on this finding, further exploration into the respective roles of the redox-active sites in plant QSOX and the reason for their concatenation is warranted.
Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
Keren
K
Limor-Waisberg
Assaf
A
Alon
Tevie
T
Mehlman
Deborah
D
Fass
D029681:Arabidopsis Proteins / Q000145:classification / Q000378:metabolism*; D002384:Catalysis; D004220:Disulfides / Q000378:metabolism; D019143:Evolution, Molecular; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D013058:Mass Spectrometry; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000145:classification / Q000378:metabolism*; D010802:Phylogeny; D013879:Thioredoxins / Q000378:metabolism
D029681:Arabidopsis Proteins; D004220:Disulfides; D005182:Flavin-Adenine Dinucleotide; D013879:Thioredoxins; D050862:Oxidoreductases Acting on Sulfur Group Donors