Protein oxidation in plant mitochondria detected as oxidized tryptophan

• Published in: Free radical biology & medicine Vol. 40; no. 3; pp. 430 - 435
• Main Authors: Møller, Ian M., Kristensen, Brian K.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2006
• Subjects: Aconitate Hydratase - metabolism; Amino Acid Sequence; Complex III; Electrophoresis, Gel, Two-Dimensional; Glycine decarboxylase; Kynurenine - analogs & derivatives; Kynurenine - metabolism; Mass spectrometry; Mitochondria; Mitochondria - metabolism; Mitochondrial processing peptidase; Mitochondrial Proteins - chemistry; Molecular Sequence Data; N-Formylkynurenine; Oxidation-Reduction; Oxidative stress; Plant Leaves - chemistry; Plant Proteins - chemistry; Protein oxidation; Sequence Homology, Amino Acid; Solanum tuberosum - chemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Superoxide Dismutase; Tryptophan; Tryptophan - chemistry; Oxidative stress; MS; GDC; Complex III; PTM; Tryptophan; SOD; Superoxide dismutase; PAGE; Glycine decarboxylase; IEF; BN; MPP; MS/MS; LC-MS/MS; Mitochondria; Protein oxidation; Mitochondrial processing peptidase; N-Formylkynurenine; ROS; Mass spectrometry
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/j.freeradbiomed.2005.08.036

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.