Protein oxidation in plant mitochondria detected as oxidized tryptophan.
The formation of N-formylkynurenine by dioxygenation of tryptophan was detected in peptides from rice leaf and potato tuber mitochondria. Proteins in matrix and membrane fractions were separated by two-dimensional gel electrophoresis and identified using a Q-TOF mass spectrometer. N-Formylkynurenine was detected in 29 peptides representing 17 different proteins. With one exception, the oxidation-sensitive aconitase, all of these proteins were either redox active themselves or subunits in redox-active enzyme complexes. The same site was modified in (i) several adjacent spots containing the P protein of the glycine decarboxylase complex, (ii) two different isoforms of the mitochondrial processing peptidase in complex III, and (iii) the same tryptophan residues in Mn-superoxide dismutase in both rice and potato mitochondria. This indicates that Trp oxidation is a selective process.
Møller
Ian M
IM
Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark. imm@kvl.dk
Kristensen
Brian K
BK
D000154:Aconitate Hydratase / Q000378:metabolism; D000595:Amino Acid Sequence; D015180:Electrophoresis, Gel, Two-Dimensional; D007737:Kynurenine / Q000031:analogs & derivatives / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D018515:Plant Leaves / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D011198:Solanum tuberosum / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013482:Superoxide Dismutase; D014364:Tryptophan / Q000737:chemistry*
D024101:Mitochondrial Proteins; D010940:Plant Proteins; C007772:N'-formylkynurenine; D007737:Kynurenine; D014364:Tryptophan; D013482:Superoxide Dismutase; D000154:Aconitate Hydratase